Photoshop 2022 grayscale images open brighter compared to Silverfast 9.1.2 - Mac OS 12.1 Monterey

[in.a.fever.dream]

I have posted this earlier but received no response under the "Bug" category. In fact I am not sure whether this is a bug or a "feature"... So here it goes (again):

I noticed that recently the images that I scan using Silverfast 9.1.2 show visibly brighter when opened in Photoshop 2022. I have been working in colour for a while and this does not seem to be an issue. Two or three months ago this also was not affecting grayscale files. I don't think I changed any settings in Silverfast and Photoshop that could result in this problem, but there were several updates in the meanwhile.

Does anyone have some suggestions what could be the reason for this?

Silverfast (the top screenshot), MacOS Preview (middle), and Photoshop (bottom - image shows slightly brighter):

[D Fosse]

No bug. In fact, Photoshop is about the only application on the planet that treats grayscale correctly.

Grayscale is subject to standard color management just like RGB. No color of course; but the tone response curve is very different in different grayscale profiles.

So does Silverfast give you a choice of grayscale icc profile? And if so, does it embed that profile in the file? An untagged grayscale file is as unpredictable as an untagged RGB file.

[Per Berntsen]

The image is indeed untagged.

I don't use Silverfast, but according to this page it does support color management, but it is turned off by default.

There are instructions on the page I linked to on how to enable it.

However, it is only possible when scanning reflective originals and positive film. There is no color management for scanning negatives.

[in.a.fever.dream]

Thank you so much for your help!
These are negative transparencies... Does that mean there's no way to avoid that difference in brightness in this case?

That also explains why the colour images were not affected so far - I was scanning mostly colour slide film (positive) and Silverfast assigned profiles to the files by default...

[Per Berntsen]

Try to assign the Gray Gamma 2.2 profile to the image, that might make it a bit darker.

Edit > Assign profile.

Some general advice on scanning negatives –

I always aim for a histogram like the one below, with plenty of space on both sides, which means that there is no shadow or highlight clipping. In other words, all the information in the negative has been captured in the scan.

The image will be flat, but that's easy to correct in Photoshop or Lightroom later.

Make sure to scan and do all edits in 16-bit.

The histogram you have in Silverfast shows clipping of both shadows and highlights, and it may be possible to recover a lot more detail, especially in the highlights.

[in.a.fever.dream]

I will try assigning the profile and let you know if that helps later. But that makes sense since the Gamma Correction is set for 2.20 in Silverfast (my screenshot).

As for the histogram - I used Multi Exposure option in Silverfast but the scan would not fit into histogram anyway. It looks like the image was overexposed. But it's also an old negative from 1930s, so perhaps the film itself is somehow affecting this as usually I have no problems with that... It feels very brittle and had definitely aged...

[D Fosse]

That's right. Those old film emulsions had very limited dynamic range, and it's almost certainly blown out in the original exposure. That's a very high contrast scene that even some modern digital sensors might have trouble with.

[Per Berntsen]

Those old film emulsions had very limited dynamic range, and it's almost certainly blown out in the original exposure. That's a very high contrast scene that even some modern digital sensors might have trouble with.

You may well be right that the highlights are blown in this image. It's been a long time since I scanned that old negatives. But I have yet to see a digital sensor that can match the dynamic range of (modern) negative film.

I worked with B&W negative large format film for 40 years, and I always paid particular attention to highlight detail. The amount of details I could bring out by burning in the highlights when printing was incredible.

In the early 90's I started to use Pyro developer, which gave me an even greater dynamic range. Pyro produces a yellow stain, and the stain increases proportionally with density, so that the highlights get the most stain.

This worked very well with Multigrade paper and a color head on the enlarger, since yellow light produces a low contrast image.

It reduced the need to burn in highlights, and when needed, they could often be brought down by a short exposure with yellow light only. (magenta light would increase the contrast)

I also did some work on color negative film (mostly Kodak VPS), which also had a huge dynamic range.

Although I started using digital cameras for commercial work around 2005, I continued to use film for my artwork until 2017, when I went all digital. I currently use a Fuji GFX 50S and a Nikon Z7, and neither of them have a dynamic range as good as negative film. You can of course expose for the highlights, at the risk of noise and poor color rendition in the shadows and midtones.

The image below was shot on Kodak TMAX 100, and the exposure was 25 seconds at f/32.

The film was developed in PMK Pyro developer, and this is a scan of the negative.

[D Fosse]

This made me curious, so I picked up my copy of Ansel Adams' "The Negative", written in 1962. On page 53, he seems to consider the useful dynamic range of black and white negative film 12 or maximum 13 stops (in the zone system, zone 0 - XII).

Of course, film didn't clip in a linear way like a digital sensor, there's a shoulder where you might be able to extract more information (but Adams seems to dismiss that).

My Sony a7rIII has a specified dynamic range of 14 stops. I haven't systematically tested that, but I have no reason to doubt it. I'm constantly amazed at how mugh highlight detail it's possible to recover. But when it's gone, it's gone.

That's a digression, sorry 😉

[Per Berntsen]

I have the revised edition of The Negative from the early 1980's, but someone borrowed it and never returned it.

So I don't know if Ansel Adams came to any different conclusions 20 years later.

In any case, I have no scientific evidence for my claims, and I never did any tests comparing the dynamic range of film and digital.

It's all based on a subjective feeling I get from working with digital cameras.

I can be facing a scene, and thinking that I need to use an extra exposure for the highlights, because the scene's dynamic range is too high. When I was shooting film, this was something I never thought about, because it wasn't a problem.

I would expose for the shadows, and develop for the highlights, and blown highlights were extremely rare, especially after I started to use Pyro developer. It was of course a big advantage to work with sheet film, since each sheet could be developed individually if needed.

[D Fosse]

Yes, that's the one I have. I think I borrowed it from someone and never returned it 😄 (just kidding).

I suspect the real reason dynamic ranges feel different is that a digital sensor hard clips - the data are all there until they suddenly aren't. Film, on the other hand, tapers softly off. I had a darkroom in the '90s, and I remember it was usually possible to squeeze just a little bit more out of those highlights.

[NB, colourmanagement]

The fact that the image is overexposed [or underexposed] doesn’t prevent you from having a histogram like Per recommends. With space at the ends, so the image is not being "clipped" [due to scanner settings]. However, even when doing that safety move, the exposure of the original CAN cause lack of detail at extremes [And plainly the scanner settings can't fix that.]

Of course. As D. Fosse wrote there may be (valuable) subtle detail in the shoulder area of the histogram so it must be preserved. A "tight" histogram (which indicates image data at 255 or 0) indicated that data may have been clipped. 

I hope this helps
neil barstow, colourmanagement net :: adobe forum volunteer
google me "neil barstow colourmanagement" for lots of free articles on colour management
[please only use the blue reply button at the top of the page, this maintains the original thread title and chronological order of posts]

[TheDigitalDog]

Silverfast should suppor color management fully (my copy does).

Next, you really need to compare the two at the same zoom ratio and at 1:1 (100%) as zooming out in either product can subsample pixels and produce an incorrect preview.

Yes, the scan from SilverFast mush have an embedded profile, it should if setup correctly, Photoshop should recognize it and at the same zoom, they should match. If not, we can go there (could be a display profile issue, GPU etc).

[in.a.fever.dream]

First of all - big thanks go to everyone here for helping me out, you are great!

Here are some facts I (we) managed to establish:

1. This was indeed a problem with a missing ICC profile in the grayscale file from Silverfast.

2. Silverfast 9.1.2 can (sceeenshot attached) create a profile for a grayscale negative. In the meantime I received the following response from Silverfast:

"SilverFast does not use embedded profiles for greyscale scans by default. To sync the appearance of the preview in SilverFast with the file opened in Photoshop, please make sure that SilverFast and Photoshop are using the same greyscale profile. In SilverFast you can select the profile in the SilverFast Preferences -> CMS.

Photoshop does also provide some "special features" like "black point compensation" or "gamma" correction you can define in the Color Management Settings.
The Rendering Intent used by the color management system can also pay a role...we are using Perceptual rendering. In Photoshop you have the options "Perceptual", "Relatively Colorimetric", "Absolutely Colorimetric" and "Saturation". Please select the perceptual one."

3. Having assigned the profile in Silverfast fixed the difference in brightness. I also changed the Rentering Intent to "Perceptual" as advised just to make sure.

[D Fosse · Accepted solution]

In the Color Settings screenshot, see the working gray "Dot Gain 15%" ? That's what is responsible for the difference you saw at first. The dot gain profiles have a tone curve very different from gamma 2.2.

That's not a problem as long as there is an embedded grayscale profile, because it will override the working gray. But without a profile, the working gray kicks in. In Photoshop, there always has to be some profile.

An alternative way to deal with it is to set working gray to Gray Gamma 2.2. You can do that in any case, but that would basically just hide the problem, not solve it. It's better to get into the habit of always having an embedded profile.

[TheDigitalDog]

Good to know that fixed your issue. FWIW, these profiles are very, very unlikely to have a Perceptual table. I suspect you can pick Perceptual and you'll get the same results as if you picked Relative Colorimetric. But that's all a minor point.