Out of Gamut Fixing Question

[teenas96182878]

I am trying to prep artwork for print on demand and have watched several videos about fixing out of gamut color but I am still not clear on if what I am doing is correct. The photo I am practicing on is my artwork of a weathered blue door, a weathered porch and then a red/gold hound on the porch. (See photo attached.) The out of gamut colors are on the door facing and door for the most part and I changed those gray colors to magenta so I could see them better. Several tutorials gave several different explanations of how to fix. One suggests creating a new adjustment layer and changing the the saturation in that layer, but when I do that and get rid of all the out of gamut magenta color, it washes out the rest of the color. Another tutorial suggested that a better way was to using edit preferences, transparency in gamut and then choosing to lighten the chosen color of blue which I am selecting but that seems to wash out the enter picture. Maybe both of these are okay because it's a masked layer but I am not sure about the results I am getting. The image certainly looks washe out. Does that sound like the right result? 

[davescm · Accepted solution]

Have you tried just using proof colours to preview the image in the printer/paper profile and seeing what it looks like with relative vs perceptual rendering intent. The trouble with the gamut warning is that it does not let you know whether the colour is just out of gamut and will be altered very slightly on printing or way out of gamut and will be altered significantly. So you might be using a sledgehammer to crack a walnut.

If the colour is way out then I would use a hue sat layer / but target that specific colour range and  minimise the adjustment to bring it close and let the ICC colour management process do the rest.

Dave

[D Fosse]

Hue/sat is fine, although personally I prefer Selective Color. It's more subtle, but also much less disruptive to the pixel structure and general image integrity.

If I have more time on my hands, I dig a little deeper to find out exactly which channel is clipping and where (high or low end). In this case, it's most likely the red channel clipping at the low end.

You can use "Blend If" to target any corrective adjustment pretty precisely to the clipped areas. Pick the red channel slider, and set it to affect the low values only. Split the slider and experiment with the range. Lower the opacity of the adjustment layer until it just brings it into gamut.

It really varies from situation to situation. If the soft proof is acceptable, just ship it and be done.

[Stephen_A_Marsh]

Is this a solution looking for a problem?

[D Fosse]

As I said, it depends. Severe gamut clipping usually looks pretty bad.

A generally dense and opaque look with no "air" is typical for out of gamut areas, and very unattractive. Squashed and flat textures don't look good either. That's when a little effort can improve the result considerably, and if it's an important image, it's definitely worth it.

Slight gamut clipping is usually not a problem, and no solution required. The profile can handle it. Not seeing the original I don't know which one we have here.

This is why soft proof is the way to go and the gamut warning useless.

[Stephen_A_Marsh]

Exactly, my reply was to teenas96182878 as it is worth checking what a preview or actual conversion using different rendering intents and options looks like, before performing a whole lot a gyrations to fix something indicated by the gamut warning that may not be an issue in the first place.

The image posted is in sRGB, but who knows what the CMYK destination condition or profile is?

It's going to be printed at some PoD provider, perhaps leaving it in RGB may offer better gamut if they have their colour workflow setup sensibly (probably doubtful, but one can hope), or perhaps the PoD plce only accepts CMYK (which CMYK???)...

[c.pfaffenbichler]

Excellent point. 

@teenas96182878  , what is the image’s RGB Space and what is the target space? 

[D Fosse]

Right, agree with that.

[teenas96182878]

I am dealing with several POD co's including Printful, Fine Art America, and Red Bubble. All of them want the image as RBG so they do the converting. I was in contact with a graphic designer from Printful to see what tips he had for getting as close as I could and he is the one who brought up tweaking the out of gamut.  He stressed that. Printful also has color swatches you can buy but you need different ones for different products so you might have to buy one for white T-shirts and one for black. I think they may have them for just prints. All 3 co's use matte paper.  He also suggested turning my monitor down to 30% brightness to get an idea of how it would look when printed bc they print much darker. I've spent a lot of time on tweaking this particular pic and learned several things along the way. I was working in the Proof Set up with the working CYMK option. What seems to work best but not perfect to get it as close as I can to what I see in the RGB is slightly tweaking the saturation (bc if I tweak much it affects other areas), cranking up vibrance and playing a little with exposure. I did try the Blend IF options but couldn't seem to get anything to look much better. Might be bc I don't fully understand how to do it.  I did figure out that I needed to tweak cyan and blue options seperately because the door and door trim fall into two different color categories. It's been a real learning curve and I do realize that I could spend days on this so I need to find a somewhat streamlined system. According to the graphic designer from Printful, the more vibrant colors that border on florescent are going to be the out of gamut issues. Believe me, it can really change what the image looks like when you go to print. Thanks for all the input. I am definitely not on the skill level as the rest of you.

[c.pfaffenbichler]

Again: what is the image’s RGB Space? 

[davescm]

Ask the printer for an ICC profile so that you can soft proof the image. He should be able to supply one if he is using a color managed workflow and converting your document himself

Dave

[Test Screen Name]

Do you understand what we're asking for when we ask you for the image's RGB space? Let us know if you need help finding out, but it's all guesswork without this. I'm thinking it might be SRGB v1.31 (Canon) but that might be a temporary space you are experimenting with.

[teenas96182878]

Nope. I have no idea what you are talking about.  I can tell you that the image I am bringing into Photoshop is a Tiff in RGB/8 Image size is 2800 x 3800, 350 rez. Once it is ready to go to the POD, Printful they will want it as 300 rez.  

I spoke with a friend who is a photographer who used to teach photoshop. She said to get a monitor calibrator (she uses ColorMunki and a separate monitor and that would take care of most of the RBG and CYMK matching issues.  She swears by that and said to try it and then to send for a sample to see how it does but she swears it should resolve just about all of the issues. I don't know how much that would help with the out of gamut. There's only so muching tweaking I can do to get it to a close match.

[D Fosse]

Until you know what a color space is, any discussion about gamuts is wasted and there's no point in going on. The whole concept relies on color spaces and their properties.

RGB is a generic color model. Color spaces are e.g. sRGB IEC61966-2.1, Adobe RGB (1998), ProPhoto RGB etc.

Color spaces have different sizes, according to where the primary colors are positioned. Anything on the inside of the color space is in gamut, anything outside it is out of gamut and cannot be reproduced in that color space.

That's all I have time for now. It shouldn't be too hard to find literature on the internet.

[teenas96182878]

Ok. Thanks

--
Teena M. Stewart

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[davescm · Accepted solution]

Hi

see if this helps your understanding of color spaces and their associated colour profiles :

Digital images are made up of numbers. In RGB mode, each pixel has a number representing Red, a number representing Green and a Number representing Blue. The problem comes in that different devices can be sent those same numbers but will show different colours. To see a demonstration of this, walk into your local T.V. shop and look at the different coloured pictures – all from the same material.

To ensure the output device is showing the correct colours then a colour management system needs to know two things.

1. What colours do the numbers in the document represent? 
This is the job of the document profile which describes the exact colour to be shown when Red=255 and what colour of white is meant when Red=255, Green = 255 and Blue =255. It also describes how the intermediate values move from 0 through to 255 – known as the tone response curve (or sometimes “gamma”).
Examples of colour spaces are (Adobe RGB1998, sRGB IEC61966-2.1)
With the information from the document profile, the colour management system knows what colour is actually represented by the pixel values in the document.

2.What colour will be displayed on the printer/monitor if it is sent certain pixel values?
This is the job of the monitor/printer & paper profile. It should describe exactly what colours the device is capable of showing and, how the device will respond when sent certain values.
So with a monitor profile that is built to represent the specific monitor (or a printer profile built to represent the specific printer, ink and paper combination) then the colour management system can predict exactly what colours will be shown if it sends specific pixel values to that device.

So armed with those two profiles, the colour management system will convert the numbers in the document to the numbers that must be sent to the device in order that the correct colours are displayed.

So what can go wrong :

1.The colours look different in Photoshop, which is colour managed, to the colours in a different application which is not colour managed.
This is not actually fault, but it is a commonly raised issue. It is the colour managed version which is correct – the none colour managed application is just sending the document RGB numbers to the output device regardless without any conversion regardless of what they represent in the document and the way they will be displayed on the output device.

2.The colour settings are changed in Photoshop without understanding what they are for.
This results in the wrong profiles being used and therefore the wrong conversions and the wrong colours.
If Photoshop is set to Preserve embedded profiles – it will use the colour profile within the document.

3.The profile for the output device is incorrect.
The profile should represent the behaviour of the device exactly. If the wrong profile is used it will not. Equally if the settings on the device are changed in comparison to those settings when the profile was made, then the profile can no longer describe the behaviour of the device. Two examples would be using a printer profile designed for one paper, with a different paper. A second example would be using a monitor profile but changing the colour/contrast etc settings on the monitor.
The monitor profile is set in the operating system (in Windows 10 that is under Settings>System>Display >Advanced) which leads to a potential further issue. Operating system updates can sometimes load a different monitor profile, or a broken profile, which no longer represents the actual monitor.

There is one more scenario that is mentioned in this thread which is "soft proofing". That means simulating what the output will look like if converted to another profile. So it is possible to simulate any colour changes that might apply when printed with a particular colour printer profile if you have that profile installed on your system - hence the advice to request a copy of teh printer profile from your printer for soft proofing.

Colour management is simple to use provided the document profile is correct, always save or export with an embedded profile, and the monitor/printer profile is correct. All the math is done in the background.

I hope that helps

Dave