The ProPhoto cyan shadow banding bug

Adobe Community Professional ,
Oct 23, 2018

Copy link to clipboard

Copied

Since Noel is back with us, I thought this header might catch his attention. He was the one who first reported it six or seven years ago.

The reason I'm bringing this up now, is that someone in the Lightroom forum had this problem just yesterday (he was sending ProPhoto files to Photoshop and couldn't understand the cyan cast in his dark grays). There's no doubt it's the same issue.

This made me dig up my old ProPhoto test gradient file. I don't use ProPhoto all that much, so I haven't really looked for it in a while. To recap, this is an example of what it could look like (this is an old screenshot that I've kept). Open and view against a darkish background:

test-PP_screenshot.png

But when I opened the test gradient now, there was no trace of it, zero. The gradient is smooth as silk. That surprised me, because while the effect can vary, it always seemed to be there in some form.

Technically, this is an inaccuracy in the conversion from ProPhoto into the monitor profile. This conversion is performed by OpenGL in the GPU when you have the PS preference set to Normal and Advanced modes. In Basic mode it's shifted back to the CPU, which is more accurate so the problem disappears. And you only see it in ProPhoto files because ProPhoto is very compressed in the shadow values compared to other color spaces. The stratospheric gamut has a price, and that's it. With this compression, inaccuracies get amplified.

So what has changed on my system over the last 12 to 24 months? Not much. I still use Eizo Colornavigator as I did then, still producing similar matrix monitor profiles. But one thing has changed - going from GeForce to Quadro, and with that, 10 bits per ch output.

So Noel, if you're reading this - I understand you have Quadro GPU too, and running displays at 10 bit. Do you still see it?

Anyone else?

Views

1.8K

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Adobe Community Professional ,
Oct 23, 2018

Copy link to clipboard

Copied

So if I understand you correctly, you are asking why you don't have a problem?


-- Johan W. Elzenga, http://www.johanfoto.com

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Adobe Community Professional ,
Oct 23, 2018

Copy link to clipboard

Copied

There is a problem, has been for a long time.

The fact that I'm not seeing it now could explain why it happens elsewhere. I'm gathering troubleshooting info.

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Adobe Community Professional ,
Oct 23, 2018

Copy link to clipboard

Copied

Dag - have you tested with Legacy Compositing checked and unchecked?

Dave

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Adobe Community Professional ,
Oct 23, 2018

Copy link to clipboard

Copied

Nope, will do.

(Although this is basically a flat file issue, no compositing involved.)

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Adobe Community Professional ,
Oct 23, 2018

Copy link to clipboard

Copied

I got the impression that the core engine was being updated to make compositing better. So there is a chance that this would be a difference. As discussed in another thread , it is difficult to tell without any firm info on what has been changed.

Dave

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Adobe Community Professional ,
Oct 23, 2018

Copy link to clipboard

Copied

Negative, Dave, no difference with legacy on or off -

How about you? If you make a radial gradient from 0 to, say, 80, in a ProPhoto file, can you see any cyanish banding?

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Explorer ,
Oct 23, 2018

Copy link to clipboard

Copied

sRGB.pngAdobe RGB.pngProPhoto RGB.png

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Adobe Community Professional ,
Oct 23, 2018

Copy link to clipboard

Copied

Yep, there it is. That's exactly how it looks.

(although, to eliminate all variables, you should do it with 16-bit files - but I doubt it will make much difference here. The crucial bit depth limitation isn't in the file, but the display system).

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Explorer ,
Oct 23, 2018

Copy link to clipboard

Copied

So this is the same issue as when I export from Lr to Ps via Edit In?

I'll try one in Basic mode and update the previous post.

Update, I can't seem to edit the previous post so here's with Photoshop in Basic drawing Mode

Ps Basic Drawing Mode.png

And here are the 16bit files. I always work in 16bit but since yours wasn't I wanted to test with the same settings.

Screen Shot 2018-10-23 at 14.25.25.png

Screen Shot 2018-10-23 at 14.27.43.png

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Adobe Community Professional ,
Oct 23, 2018

Copy link to clipboard

Copied

I just tried 6 new documents, each time before creating the I changed the drawing mode. I then used the gradient tool

Results:

Prophoto 16 bit - Basic - Banding    Edit : Pro Photo 16 bit Basic No (or at least barely visible) banding
Prophoto 16 bit - Normal - Banding

ProPhoto 16 bit - Advanced - Banding
Switching between the docs prepared with different drawing modes  - the banding does not change at all

Adobe 1998 -16 bit - Basic - No (or at least barely visible) banding
Adobe 1998 -16 bit - Normal - No (or at least barely visible) banding
Adobe 1998 - 16 bit - Advanced - No (or at least barely visible) banding

My monitors are not 10 bit - hence the "barely visible" comment

Dave

Edited : I had started new documents but not restarted Photoshop between drawing modes

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Adobe Community Professional ,
Oct 23, 2018

Copy link to clipboard

Copied

You shouldn't get this in Basic mode. You obviously know that changing drawing mode requires relaunching Photoshop, so I will not remind you about that

Is the banding cyan colored (that's the smoking gun), or just regular banding? See my original screenshot at the top.

OK. I suppose everyone has more than enough to chew on these days, between color blend bug, constrained scaling and file associations, so I won't stress this too much now. I was just curious. Also, I need to mind my job inbetween...

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Explorer ,
Oct 23, 2018

Copy link to clipboard

Copied

Was thinking the same, this should not happen in Basic mode, if so then it's an even more complicated issue!

We need to work indeed but then Lr and Ps are my main tools for work so I would rather see this issue resolved.

One question D Fosse, you mentioned not using ProPhoto does that mean you use Adobe RGB color space in your workflow? do you work with JPG or RAW files? shouldn't we all be using ProPhoto RGB especially with RAW files to keep as much detail (color, dynamic range, etc..) as possible. At least my experience shows there's a pretty big difference. Same with gradients. Masks I believe though are always 8bit but one can barely notice the difference. Even Lightroom recommends using ProPhoto RGB.

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Adobe Community Professional ,
Oct 23, 2018

Copy link to clipboard

Copied

I try to avoid ProPhoto if possible, because of the compressed shadows. I'm really bothered by that - it's really difficult to make subtle shadow adjustments. I do use it when I need the extended gamut, but I prefer Adobe RGB if gamut clipping can be controlled in other ways.

Controlling clipping is the main thing, and sooner or later you will have to remap those ProPhoto files into something smaller anyway.

There's no other advantage to ProPhoto than the extremely large gamut. If you don't need that, there's no particular reason to use it. It doesn't give you any more dynamic range.

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
LEGEND ,
Oct 23, 2018

Copy link to clipboard

Copied

See whether Use Graphics Processor is enabled or disabled in your Performance Prefs, and what Drawing Mode you're set to use.  As I recall setting the latter to Basic moved the color-management tasks into the CPU and that worked around the problem.

I just reproduced the problem here on 20.0.0, 30 bit color, with the nVidia 391.89 driver.  For a gray graident in a ProPhoto RGB document going from levels 12 to about 90 I see concentric rings of cyan and gray.  They look nice and smooth with the 30 bit color, but the color inaccuracy is definitely there.  Here's a saturation-enhanced screen grab (which necessarily reduces the image to 8 bit color)...

ColorInacccuracy.png

I know you've recently updated your nVidia display driver, Dag, to 4xx.something.  I've been meaning to do that myself.  I will do so shortly and report back.

-Noel

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Explorer ,
Oct 23, 2018

Copy link to clipboard

Copied

It looks compressed but isn't this because the image is dark and has more a lot more information in the ProPhoto space?

As you already guessed though I'm not an expert in this, by far, I wish though so I could solve this problem. I certainly know my way around Lr and Photoshop where image editing is concerned but this stuff makes my head spin.

Adobe RGB vs ProPhoto RGB

AdobeRGB.png

ProPhotoRGB.png

Now I'm deciding between ProPhoto RGB with Basic or Adobe RGB with Advanced. This is with RAW files, final export to sRGB or aRGB, depends on the library I submit to. Do you think I won't miss much by using Adobe RGB? If I was shooting JPG then sure it would make no sense to work in ProPhoto although.... I've read you can get smoother gradients (or other edits) when converting to 16bit and then save back to 8bit.

Oh and WELCOME BACK NOEL!!!

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Adobe Community Professional ,
Oct 23, 2018

Copy link to clipboard

Copied

Thanks Noel, so it's still there...dang. Well, try 411.63 when you get to it.

I had a secret hope that the Quadro drivers would prove to be more accurate, and that be the explanation. Not because I would persuade everyone to buy one, but just to have an explanation and a way out for those bothered by this.

Yes, I have GPU enabled and set to Advanced, and no banding whatsoever in ProPhoto files, which is a sensational first. It's always been there before <scratches head>.

Oh well, back to square one. Maybe it's just an inherent problem in OpenGL code, nothing to do with Adobe or any other implementation of it.

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Explorer ,
Oct 23, 2018

Copy link to clipboard

Copied

I cannot believe we're the only ones noticing this issue, this is in B&W....or is it color?

I've been using Basic drawing mode for ages now because of this and even bought a new GPU a week ago to solve this.

Alright I'll do some more testing to see if I can make the switch to AdobeRGB working space (advanced)

Screen Shot 2018-10-23 at 16.52.45.png

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Adobe Community Professional ,
Oct 23, 2018

Copy link to clipboard

Copied

https://forums.adobe.com/people/D+Fosse  wrote

You shouldn't get this in Basic mode. You obviously know that changing drawing mode requires relaunching Photoshop, so I will not remind you about that

Embarrassed time. I was thinking it was the same as GPU on off and just needed a new document start. I'll retest later tonight

Dave

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
LEGEND ,
Oct 23, 2018

Copy link to clipboard

Copied

Hi Dag,

Oops, got nVidia 411.81 here.  Apparently released today.  I'm still on Windows 8.1 by the way.  The problem remains.

Whatever you've got going on, treasure it.    In all seriousness, it's good that you've picked this issue back up.  Maybe the difference will lead to a discovery.

-Noel

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Adobe Community Professional ,
Oct 23, 2018

Copy link to clipboard

Copied

https://forums.adobe.com/people/D+Fosse  wrote

Yes, I have GPU enabled and set to Advanced, and no banding whatsoever in ProPhoto files, which is a sensational first. It's always been there before <scratches head>.

BTW I'm not seeing any banding either on my Windows 7 system using a Quadro 600 GPU.

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
LEGEND ,
Oct 23, 2018

Copy link to clipboard

Copied

By the way, do you have the Use native operating system GPU acceleration setting available and checked in the Advanced Graphics Processor Settings panel.  It's grayed out for me; I imagine it's only available for the very latest OS versions.

AdvancedGPU.png

-Noel

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Explorer ,
Oct 23, 2018

Copy link to clipboard

Copied

Yup, uses Metal in macOS (Mojave here)

Screen Shot 2018-10-23 at 17.57.36.png

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
LEGEND ,
Oct 23, 2018

Copy link to clipboard

Copied

By the way, here's an image that can be used to reproduce the issue directly.  Just open it into Photoshop; you should be able to see the circular bands of color if you look carefully.  It's a 16 bits / channel PNG file with a smooth radial gray gradient.

Make sure that when you open the file it doesn't get converted to your preferred color space (look in Edit > Color Settings... for the rules for that).

https://Noel.ProDigitalSoftware.com/ForumPosts/GrayRadialGradientProPhoto.png

I'm not sure of the best way to get it from my site to your Photoshop.  Maybe right-click, download, or copy and paste the URL into the Photoshop File > Open dialog.

-Noel

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Explorer ,
Oct 23, 2018

Copy link to clipboard

Copied

Indeed, Web (converted to sRGB I suppose) and Ps version side by side

Screen Shot 2018-10-23 at 18.00.08.png

Btw are we in a private room listening to our own echos or are Adobe engineers actually looking into these threads?

We really need to get our hands on one of those engineers asap, I'll bring the chair, you bring the rope, D Fosse can ask the questions!

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Adobe Community Professional ,
Oct 23, 2018

Copy link to clipboard

Copied

That "use native os gpu acceleration"-checkbox is grayed out here too. It has to refer to the Metal framework in MacOS. I'd forgotten all about that - isn't that supposed to replace OpenGL in MacOS?

In that case the plot thickens, because then it isn't OpenGL either. You get the cyan banding with Metal too!

So what are we left with? The monitor profile? I use Colornavigator profiling software, but I've done that for many years. Todd uses NEC Spectraview with a PA272, right?

Display system bit depth? No. Noel has a 30-bit system too.

Huh.

WLan, we once got an engineer to promise to look into this, but that was the last we heard (Chris Cox, who later left Adobe).

Oh, and BTW, I've double-checked both on my home and work systems, no difference, but I didn't expect that since they are identically configured in all important aspects.

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Adobe Community Professional ,
Oct 23, 2018

Copy link to clipboard

Copied

https://forums.adobe.com/people/D+Fosse  wrote

So what are we left with? The monitor profile? I use Colornavigator profiling software, but I've done that for many years. Todd uses NEC Spectraview with a PA272, right?

Display system bit depth? No. Noel has a 30-bit system too.

Yes, NEC Spectraview with a PA272, but no 30 bit display mode. I had an issue with DisplayPort not waking sometimes on my Windows 7 system and 30 bit display got broken on one of the updates so I gave up.

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Adobe Community Professional ,
Oct 23, 2018

Copy link to clipboard

Copied

Hi

After restarting each time the revised results in here. This is on an NVidia GTX 1080 OC with driver 416.34

Results:

Prophoto 16 bit - Basic - No (or at least barely visible) banding
Prophoto 16 bit - Normal - Banding

ProPhoto 16 bit - Advanced - Banding

Adobe 1998 -16 bit - Basic - No (or at least barely visible) banding
Adobe 1998 -16 bit - Normal - No (or at least barely visible) banding
Adobe 1998 - 16 bit - Advanced - No (or at least barely visible) banding

My monitors are not 10 bit - hence the "barely visible" comment

Apologies for the false steer earlier

Dave

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Adobe Community Professional ,
Oct 23, 2018

Copy link to clipboard

Copied

Yep, that's the expected result, Dave.

Interesting problem, huh? What on earth could cause this?

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
LEGEND ,
Oct 23, 2018

Copy link to clipboard

Copied

My inner geek voice has always whispered a suspicion that there must be a stage in the  transform calculation in which, even though GPUs use floating point math, a number near an integer may be subtracted from a nearby integer (e.g., 1 - 0.9999999), which is a sure way to cause precision loss.  Another thought is that maybe there are tone curves that differ by a very small amount for each of the colors.  An amount some profile designer thought was inconsequential 20 years ago.

It is possible the monitor profile is involved, though I have verified seeing the issue using anything from the age-old sRGB v2 profile to newer v4 display profiles as a display profile. 

It's clearly got to do with using the ProPhoto profile as a working space, because another, similar profile (e.g., ColorMatch RGB) doesn't cause it - which led me to wonder further...  Could there now be more than one ProPhoto RGB profile around?  Could you have somehow gotten an updated one, Dag, that no longer causes the precision loss?

I looked on my hard drive and I saw that I actually have accumulated multiple copies of the ProPhoto profile (not surprising), BUT...  I do have two different renditions.  Most are ProPhoto.icm (including the one in C:\Windows\System32\spool\drivers\color, which is the one that matters), dated anywhere from 2005 to 2015.  the one that's different is ProPhoto.icc (note the different file extension) dated 2012, and located in a folder created by a different photo editor (ComputerInsel Photoline).  Turns out it's described as "ProPhoto RGB (linear)" and it isn't another rendition of the same profile, exactly, but its existence DOES support the possibility of there being alternate versions of ProPhoto.icm running around in the world.


Dag, is your copy of C:\Windows\System32\spool\drivers\color\ProPhoto.icm the same size as mine?

ScreenGrab_NoelC4_2018_10_23_194830.png

If so, next we can devise a way to see if they contain the exact same binary data.

-Noel

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Adobe Community Professional ,
Oct 24, 2018

Copy link to clipboard

Copied

Yes, down to the last byte (940/4096).

But even if the gradient looks fine, there's something funny going on all right. I drew a marquee and cranked saturation all the way up. Why is it consistently red when it should just be neutral with increased color noise? What's that cyan peak in the histogram?

PP_cyan_1.png

Yeah, it could be the PP profile spec in itself. Now, I'm a practical man. I know how things work, but whenever someone tries to drag me into the Hogwarts Color Science Lab, I'm off chasing butterflies. I know nothing about the internal anatomy of a profile - except the broad principles of Profile Connection Spaces. I know there's a table somewhere (way up in the Scottish Highlands), which can be based on either XYZ or Lab. Could this be where the dragon is buried?

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Adobe Community Professional ,
Oct 24, 2018

Copy link to clipboard

Copied

I have both an .icm an .icc ProPhoto RGB profile on my Windows 7 system, but in PS Color Settings I only see one ProPhoto RGB selection. They appear to be identical so it shouldn't matter. The date showing in ICC Profile Inspector is 1998/12/1.

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
LEGEND ,
Oct 24, 2018

Copy link to clipboard

Copied

Hm, that might imply your gradient isn't pure gray, Dag, BUT...  There is definitely some additional weirdness going on!

I tried raising the saturation of my grayscale PNG to +100 and got this:

OneSaturationIncrease.png

Then I did it AGAIN and got this cute little result. 

TwoSaturationIncreases.png

After undoing all the above, I did Image > Adjust > Desaturate it, then two iterations of +100 saturations and got this:

DesaturatedFirst.png

This implies the PNG actually has some values that are non-gray (by a tiny bit).  And here I thought PNG compression was lossless - but I guess not!  The funny thing is that this little revelation seems to be entirely separate from the ProPhoto cyan cast display bug.

The plot thickens!  I'm going to save my test image as a PSD and use that from now on.  I hope THAT's lossless.

-Noel

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Adobe Community Professional ,
Oct 24, 2018

Copy link to clipboard

Copied

This is OSX High Sierra with CC2018. I'm not seeing any objectionable banding or color shifts

Screen Shot 6.png

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
LEGEND ,
Oct 24, 2018

Copy link to clipboard

Copied

It's great to see that it CAN work.  Now to figure out what's common among the systems on which it IS working, and that's proving non-trivial.

Rob, some questions, just to be thorough:

1.  Do you have your Use Graphics Processor setting checked, and are you using either Normal or Advanced graphics mode?

2.  Did you try two iterations of Saturation +100 on that .png I posted?

-Noel

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Adobe Community Professional ,
Oct 24, 2018

Copy link to clipboard

Copied

These are my Performance settings

Screen Shot 7.png

Multiple applications of the +100 Saturation makes no difference—the RGB values remain equal, which is expected.

If you add Color Sample marks to your Saturation selection do the RGB values change? Saturation shouldn't have any affect on equal RGB values. Are you testing in 2019?

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
LEGEND ,
Oct 24, 2018

Copy link to clipboard

Copied

I tested above in 2019, but I've seen the ProPhoto cyan cast issue before in 2018 and earlier versions, going all the way back.  Apparently it's appearance is dependent on something we've yet to nail down.

The second issue, which I just uncovered above, may be my fault.  I re-opened the PNG file I posted above and I haven't been able to reproduce bringing out any weird colors with any number of Saturation steps.  I may have opened a different test file from my History to get the effect with the neat patterns.

Here are reproductions of the ProPhoto cyan cast problem, with settings like yours...

Photoshop CC 2018 "girl in drug cloud splash screen edition":

PhotoshopCC2018ProPhotoRendition.png

Photoshop CC 2019 "cloud headed dude splash screen edition":

PhotoshopCC2019ProPhotoRendition.png

As you can see, even with the same settings you're using (e.g., no 30 bit in my case) the color banding remains.

The samples all show equal R, G, and B values, whether or not point samples or averaged samples are made.  It must be purely a monitor display issue.

The cyan banding issue doesn't show up in the Navigator display, by the way.  I believe Photoshop must always use CPU color-management for that.

-Noel

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Adobe Community Professional ,
Oct 24, 2018

Copy link to clipboard

Copied

It must be purely a monitor display issue.

Or an OS issue?

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Adobe Community Professional ,
Oct 24, 2018

Copy link to clipboard

Copied

No. Could be on Mac; not on Windows. Unlike MacOS, Windows doesn't touch this stuff. It's strictly application.

(EDIT: what made me pick this up again now, was a Mac user on the Lightroom forum three days ago having this exact issue. He's on Mojave and PS 20.0)

Anyway, Noel, you were right of course. Once I punched in the numbers and double-checked with 16 bit readout that R=G=B, I got this, and that's 100+ saturation on the actual finished screenshot. A few stray pixels, that's all:

grad+sat_2.png

On the upside, this is as close to perfection as it'll ever get. So yes, it can work.

It has to be somewhere in the conversion from ProPhoto source to monitor RGB.

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Guide ,
Oct 24, 2018

Copy link to clipboard

Copied

https://forums.adobe.com/people/Noel+Carboni  wrote

Hm, that might imply your gradient isn't pure gray, Dag, BUT...  There is definitely some additional weirdness going on!

I tried raising the saturation of my grayscale PNG to +100 and got this:

Then I did it AGAIN and got this cute little result. 

After undoing all the above, I did Image > Adjust > Desaturate it, then two iterations of +100 saturations and got this:

This implies the PNG actually has some values that are non-gray (by a tiny bit).  And here I thought PNG compression was lossless - but I guess not!  The funny thing is that this little revelation seems to be entirely separate from the ProPhoto cyan cast display bug.

The plot thickens!  I'm going to save my test image as a PSD and use that from now on.  I hope THAT's lossless.

-Noel

I opened your file in PhotoLine to check if the ProPhoto ICC profiled PNG file has any issues, and increased the saturation 6 times. Result: it stays neutral, no colour changes at all.

As far as I can tell, there is no issue with the PNG file itself. There don't seem to be any outlier values.

I did a second test to check if OpenGL might be the problem, and opened the file in Krita (which also uses OpenGL for its viewport). I applied the same saturation test, and no issues were encountered. (I run an Nvidia 1080GTX.)

Which leads me to believe that neither the PNG file, nor OpenGL are the problem here (at least, Nvidia's OpenGL on Windows).

PS A gut feeling tells me it might (just might) have something to do with Photoshop's (2^15)+1 internal representation in 16bit mode and calculation inaccuracies. Noel Carboni expressed similar thoughts a few years ago in this thread:

OpenGL inaccuracies and black levels

But only a Photoshop developer might know. Chris Cox would have known 😉

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
LEGEND ,
Oct 24, 2018

Copy link to clipboard

Copied

Yeah, I think that weird blotchy color thing was me opening an intermediate file I had created in a different folder on the way to making that proper grayscale PNG.  Sorry for muddying the water with that.

The cyan banding problem with previews of images expressed in the ProPhoto RGB color space is still a real issue, however.

-Noel

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Adobe Community Professional ,
Oct 25, 2018

Copy link to clipboard

Copied

Rayek, don't forget that this has never been an issue when Photoshop handles the ProPhoto > Monitor conversion natively, in Basic mode.

It only happens when the GPU takes over that particular function, in Normal and Advanced modes.

What could possibly be an issue, however, is if there is an inconsistency in how Photoshop represents data on one side, and how the GPU represents it on the other (or how it expects it to be represented).

Either way, this has to be in the simple chain ProPhoto > converted into > monitor profile. One of those three, or a combination.

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Adobe Community Professional ,
Oct 25, 2018

Copy link to clipboard

Copied

Interesting though that the GPU handles a similar conversion from Adobe RGB without issue, where the same 15+1 bit and floating point math would apply.

Dave

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Adobe Community Professional ,
Oct 25, 2018

Copy link to clipboard

Copied

Yes, but ProPhoto will naturally be more susceptible to small inaccuracies. That stratospherically huge gamut goes into the same numerical range.

There's no free lunch, everything has a price. Going from sRGB to Adobe RGB is an incremental gamut increase - mainly extending the green primary - but going to ProPhoto is jumping off the edge of the world. It's huge.

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Adobe Community Professional ,
Oct 25, 2018

Copy link to clipboard

Copied

but going to ProPhoto is jumping off the edge of the world. It's huge.

When it comes to CMYK print output I can see some advantage of the larger ProPhoto gamut, but I'm having a hard time finding the downside.

Here's the shadow gradient we've been looking at, which is obviously in gamut with both ProPhoto and AdobeRGB, and is also inside any CMYK gamut. The three color swatches are inside the ProPhoto and GRACol Coated CMYK gamut, but are out of the AdobeRGB gamut. The bottom capture is a Relative Colorimetric conversion of the Prophoto file to AdobeRGB.

Screen Shot 11.png

If I convert both to GRACol I get identical output numbers in the shadow gradient, but the numbers for the saturated colors are different—the AdobeRGB colors have been somewhat clipped.

Screen Shot 12.pngScreen Shot 13.png

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Adobe Community Professional ,
Oct 25, 2018

Copy link to clipboard

Copied

https://forums.adobe.com/people/rob+day  wrote

but going to ProPhoto is jumping off the edge of the world. It's huge.

When it comes to CMYK print output I can see some advantage of the larger ProPhoto gamut, but I'm having a hard time finding the downside.

I do a lot of scannerless color negative film capture using a DSLR copier. I open the raw files in LR and apply white balance and exposure adjustment to center image data in the histogram. Using Edit in PS I then use an action that inverts the image and applies an auto curves adjustment (Find Dark & Light Colors and Snap Neutral Midtones). I've been using ProPhoto RGB images and working space with good results. If I switch to Adobe RGB the results are considerably different and less accurate (reds more saturated). Not sure why since there is very little image area out of Adobe RGB gamut.

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Adobe Community Professional ,
Oct 25, 2018

Copy link to clipboard

Copied

If I switch to Adobe RGB the results are considerably different and less accurate (reds more saturated). Not sure why since there is very little image area out of Adobe RGB gamut.

That would be expected if you capture the same RGB values but then assigned (rather than convert to) different profiles. Try capturing with ProPhoto and then do a Convert To AdobeRGB.

In my example I'm duplicating the ProPhoto RGB file and converting it to AdobeRGB, so the displayed color appearance doesn't change. The conversion of both to the GRACol print output space generally produces the same output numbers with the exception of the colors like 100% cyan that are outside of the AdobeRGB space, but are in the GRACol space.

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
LEGEND ,
Oct 25, 2018

Copy link to clipboard

Copied

Hey Dag, if you're still seeing your ProPhoto documents without the cyan banding, could you please share your copy of the ProPhoto.icm file?  I want to see if there could possibly be a difference.

-Noel

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Adobe Community Professional ,
Oct 25, 2018

Copy link to clipboard

Copied

https://forums.adobe.com/people/rob+day  wrote

If I switch to Adobe RGB the results are considerably different and less accurate (reds more saturated). Not sure why since there is very little image area out of Adobe RGB gamut.

That would be expected if you capture the same RGB values but then assigned (rather than convert to) different profiles. Try capturing with ProPhoto and then do a Convert To AdobeRGB.

Nope. I'm using 'Covert to Profile' for the ProPhoto RGB conversion to Adobe RGB.

It probably is due to the Auto Curves function rendering the image differently due to RGB channel differences (see below). Processing color film images in LR/PS can be a PITA due to the  mask and color characteristic differences of the various color film types. However, using ProPhoto RGB with the Auto Curves function works quite well to color correct the film images.

Color Fim Processing.jpg

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Adobe Community Professional ,
Oct 25, 2018

Copy link to clipboard

Copied

On a conversion I would expect the histogram and image RGB values to change as you are showing, but not the color appearance. What happens to the histograms if you convert the two versions to the same CMYK output profile?

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Adobe Community Professional ,
Oct 25, 2018

Copy link to clipboard

Copied

https://forums.adobe.com/people/Noel+Carboni  wrote

Hey Dag, if you're still seeing your ProPhoto documents without the cyan banding, could you please share your copy of the ProPhoto.icm file?  I want to see if there could possibly be a difference.

-Noel

I sent a copy to the PDSdotcom mail - let me know if you don't get it.

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
LEGEND ,
Oct 25, 2018

Copy link to clipboard

Copied

Ah well, the file is identical to what I have.

I'm out of ideas for the moment, except perhaps that the disappearance of the bug has to do with planetary alignment...

-Noel

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Adobe Community Professional ,
Oct 25, 2018

Copy link to clipboard

Copied

Well, whatever can be eliminated is useful.

Let's think about black point compensation in monitor profiles. sRGB - which also shows this cyan banding when used as monitor profile - has its own twist on that, with the near-black linear "toe". Could that mean something? Just throwing darts blindfolded here...but maybe try Adobe RGB just for the heck of it? I know it's wrong for standard gamut displays, but just to test.

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Adobe Community Professional ,
Oct 25, 2018

Copy link to clipboard

Copied

https://forums.adobe.com/people/rob+day  wrote

On a conversion I would expect the histogram and image RGB values to change as you are showing, but not the color appearance. What happens to the histograms if you convert the two versions to the same CMYK output profile?

'Convert to Profile' U.S. Web Coated (SWOP) v2 for both produces identical Histograms with Cyan and Black channels clipped.

Color Fim Processing2.jpg

Color Fim Processing3.jpg

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
LEGEND ,
Oct 25, 2018

Copy link to clipboard

Copied

At this point I'm convinced there's something special about the ProPhoto profile itself.

A (small) new piece of info.  I had thought that my own software was rendering the grayscale completely as gray, but lo and behold (and this is something I see in @rob day's post above as well) with extreme saturation there are tiny color errors in single pixels right at the transitions between adjacent levels (in the 8 bit screen grab world).  That probably made no sense.  This hyper saturation-enhanced comparison may help (Photoshop display on top, what I *thought* was a correct rendition on the bottom, but look closely):

ScreenGrab_NoelC4_2018_10_25_150006.png

Those tiny lines show up in @rob day's screen grabs above if you push the saturation way up.

Dag, please do a screen grab of the gray gradient as displayed on your system, hyper-saturate it, and post it here.

I  wonder if these color inconsistencies are just a matter of magnitude, always there (because of something about the ProPhoto profile) but being (mostly) covered up by roundoff error in some cases and not in others.

-Noel

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Adobe Community Professional ,
Oct 25, 2018

Copy link to clipboard

Copied

I had thought that my own software was rendering the grayscale completely as gray, but lo and behold (and this is something I see in @rob day's post above as well)

My (OSX) capture is monitor RGB with my monitor profile assigned. Before I uploaded it I converted it to sRGB, so the values are no longer perfectly equal after the multiple conversions.

Screen Shot 5.png

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Adobe Community Professional ,
Oct 26, 2018

Copy link to clipboard

Copied

https://forums.adobe.com/people/Noel+Carboni  wrote

Dag, please do a screen grab of the gray gradient as displayed on your system, hyper-saturate it, and post it here.

OK, this is a screenshot of the original ProPhoto file as displayed.

Then I put 6 hue/sat layers on top, cranked them all up to 11 on the dial, and flattened.

To minimize random errors in post-conversions, this is a 10-bit screenshot pasted into a 16-bit file, monitor profile assigned > converted to sRGB, then converted down to 8 bit and saved as PNG. Phew.

screenshot_PP_hypersat.png

My own sneaking suspicion, echoing Noel's, is that ProPhoto is simply too large for its own good. Insert a dust grain of a tiny imperfection, and bam - it blows up.

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Adobe Community Professional ,
Oct 26, 2018

Copy link to clipboard

Copied

ProPhoto is simply too large for its own good

But I get the screen capture artifacts with sRGB—no conversions. Here's the gradient created from scratch in a 16-bit sRGB doc and then captured:

Screen Shot 10.png

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Adobe Community Professional ,
Oct 26, 2018

Copy link to clipboard

Copied

Yes, but here I thought mostly of the full-blown cyan banding, often coupled with severe luminance banding, which is particular to ProPhoto. Like the example up there in my original post. You never see that in Adobe RGB.

The random edge pixels that you and I both get are curious, but not something of any practical significance.

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Adobe Community Professional ,
Oct 26, 2018

Copy link to clipboard

Copied

'Convert to Profile' U.S. Web Coated (SWOP) v2 for both produces identical Histograms

Yes, in gamut colors with the same appearance in the different spaces should convert to the same CMYK output numbers. Only colors that are outside of AdobeRGB's gamut, but inside of SWOP (i.e., 90-100% cyan towards green), would show a difference in the conversion to the print space. If your example image is headed for a print destination, it wouldn't benefit from being in the larger ProPhoto space, but it shouldn't be hurt by it either.

with Cyan and Black channels clipped.

The black separation histogram would be affected by the CMYK profile's black ink limit (90% for SWOP), black generation/GCR, and total ink limit (300% for SWOP).

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Adobe Community Professional ,
Oct 26, 2018

Copy link to clipboard

Copied

The random edge pixels that you and I both get are curious, but not something of any practical significance.

I assumed they were being introduced via the screen capture? I get similar capture artifacts no matter what the profile assignment is, but they never show in the file that's being captured, either in appearance or the numbers. I'm not doubting that it's a problem, I just can't reproduce it.

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Adobe Community Professional ,
Oct 26, 2018

Copy link to clipboard

Copied

https://forums.adobe.com/people/D+Fosse  wrote

https://forums.adobe.com/people/Noel+Carboni   wrote

Dag, please do a screen grab of the gray gradient as displayed on your system, hyper-saturate it, and post it here.

OK, this is a screenshot of the original ProPhoto file as displayed.

Then I put 6 hue/sat layers on top, cranked them all up to 11 on the dial, and flattened.

To minimize random errors in post-conversions, this is a 10-bit screenshot pasted into a 16-bit file, monitor profile assigned > converted to sRGB, then converted down to 8 bit and saved as PNG. Phew.

I followed the above procedure and see no artifacts other than normal banding due to 8 bit display path.

WIndows 7, PS 19.1.6, Quadro 600 GPU, No 30 bit mode

Gray Gradient ProPhoto RGB with 6 Saturation 100.jpg

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
LEGEND ,
Oct 26, 2018

Copy link to clipboard

Copied

https://forums.adobe.com/people/rob+day  wrote

I get similar capture artifacts no matter what the profile assignment is, but they never show in the file that's being captured, either in appearance or the numbers. I'm not doubting that it's a problem, I just can't reproduce it.

Curiouser and curioser...  Yes - I also see that with any profiles that don't match my reference sRGB monitor profile only when CPU-based color-management is being done, not when GPU-based color-management is being done.  This is a surprise to me; I've always assumed the grayscale was pure, because without so much extra saturation the errors are not perceptible.

Each of these are gray gradient fill layers expressed in the listed profiles, displayed on my monitor, screen grabbed, and saturation of the screen grab increased to +100 twice.

This forum botches up image attachments, but note the major color inaccuracy in 1 of the 4 images in the first set, and tiny pixel-width lines in 3 of the 4 images in the second set.

As displayed in Photoshop CC 2019 with GPU color management:

GPUColorManagement.png

As displayed in Photoshop CC 2019 with CPU color management:

CPUColorManagement.png

-Noel

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
Adobe Community Professional ,
Oct 26, 2018

Copy link to clipboard

Copied

https://forums.adobe.com/people/rob+day  wrote

'Convert to Profile' U.S. Web Coated (SWOP) v2 for both produces identical Histograms

Yes, in gamut colors with the same appearance in the different spaces should convert to the same CMYK output numbers. Only colors that are outside of AdobeRGB's gamut, but inside of SWOP (i.e., 90-100% cyan towards green), would show a difference in the conversion to the print space. If your example image is headed for a print destination, it wouldn't benefit from being in the larger ProPhoto space, but it shouldn't be hurt by it either.

Thanks Rob. If  you look at the screenshot at the bottom of my reply #54 you can see a large difference in color of the red jacket when using Adobe RGB versus ProPhoto RGB. From my experience processing numerous color negative film types ProPhoto RGB provides the most accurate color correction using PS Auto Curves. Its an esoteric process that I don't fully understand, but it works very well. For this specific type of image processing ProPhoto RGB is needed.

If interested you can download an article Mark Segal and I wrote along with my PS Action and a color negative CR2 file for testing here:

https://www.dropbox.com/home/DSLR%20Film%20Copier

Sorry for cross-posting this issue. I just wanted to show that there are some applications where using ProPhoto RGB can make a significant difference.

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
LEGEND ,
Oct 26, 2018

Copy link to clipboard

Copied

Further experimentation reveals the results are changed by the choice of color engine one makes in the Edit > Color Settings...   If for example I choose the Microsoft ICM color engine instead of Adobe (ACE), I see a noticeable shift in the color inaccuracy and brightness of the dark parts (they're brighter with the Microsoft ICM).  I don't see a difference by tweaking the 3 checkboxes, but I haven't done an exhaustive test.

Here's what I've got for color settings:

ScreenGrab_NoelC4_2018_10_26_100352.png

Note that closing and restarting Photoshop is required to see the change take effect.

-Noel

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...
LEGEND ,
Oct 24, 2018

Copy link to clipboard

Copied

This is the one I have; looks to match yours, Todd, though of course we're not seeing all the detail in the tables.

ScreenGrab_NoelC4_2018_10_24_115156.png

-Noel

Likes

Translate

Translate

Report

Report
Community Guidelines
Be kind and respectful, give credit to the original source of content, and search for duplicates before posting. Learn more
Reply
Loading...