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Thread: Out of gamut colors and color shift

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    Out of gamut colors and color shift

    I recently did a shoot that had quite saturated colors in it. I am preparing the final files for srgb jpg print files.

    Because of the color saturation in several of the images, I check the gamut warning and have seen that there are some problem spots.

    I have some questions.

    1. When you get a gamut warning in a dark spot of the image... does it just mean it will print as pure black?

    2. Does a gamut warning in a saturated color mean it shift color when it prints?

    The reason I ask is that I did a soft proof using the adorama icc profiles on an unmodified jpg and noticed the lips went from a fuscia color to burgundy.

    Is there a way to prevent the color shift and keep nice saturation? What is the best way to correct out of gamut areas without killing the saturation?

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    Re: Out of gamut colors and color shift

    The first thing you need to check when looking at gamut warning is what profile Photoshop is using to calculate the gamut. By default, that is usually whatever CMYK profile happens to be loaded. If that's what you are using, then you're not getting an accurate gamut warning. You need to make a custom preview using the output profile of the device you are print to, and even then, it's not necessarily all that accurate.

    What kind of printer are you printing to? If it's a printer with a much larger than sRGB gamut then you're shooting yourself in the foot by using sRGB. If it's a chromogenic printer like Fuji or Chromira, etc, then sRGB is actually pretty close to the papers used in them.

    "1. When you get a gamut warning in a dark spot of the image... does it just mean it will print as pure black?"

    Not necessarily. It depends on how dark the area is, how much color is in that area and what the actual capabilities of the printer are in that area. On most printers, anything under about 12-15 RGB in the original file are going to print black.

    "2. Does a gamut warning in a saturated color mean it shift color when it prints?"

    Yes, it does, but how much it shifts and how visible it will be will depend on the image and the type of paper. What the gamut warning does not tell you, and what makes it a lot less useful than many people think, is just how far out of gamut an area is, just that it IS out of gamut. An are barely out of gamut and an area far out of gamut both show as simple "out of gamut." In the real world, you rarely notice areas that are slightly to moderately out of gamut. You also have the option of using Perceptual rendering intent to compress the colors rather than just clipping them. Or, you can do what I do in many images, convert a duplicate of the image with Perceptual and the original copy with Relative then paste the Perceptual into the Relative and mask to suit. Of course, you need to have the output profile and the lab needs to know that you have pre-converted.

    "The reason I ask is that I did a soft proof using the adorama icc profiles on an unmodified jpg and noticed the lips went from a fuscia color to burgundy."

    Fuscia to burgundy is a bit extreme, but chromogenic papers are notoriously limited in gamut, so it might be possible. Or it's just a crappy profile

    " there a way to prevent the color shift and keep nice saturation? What is the best way to correct out of gamut areas without killing the saturation?"

    If you've got severely out of gamut areas, you only have a few options. You can discard all out of gamut colors and print the in gamut colors "as is" using Relative Colorimetric. You can use Perceptual and let the tables in the profile move the out of gamut colors to the nearest in gamut color while at the same time moving the in gamut colors closer together to attempt to maintain the visual appearance of the original. The third thing you can do is to use a more complicated move using a copy of the channel with the best detail in it, duplicated, copied and pasted as a new channel with the blend mode changed to Luminosity, then masked to suit. That can put lost detail back into areas of high saturation and give the impression of higher saturation even though in reality it's lower.

    One more thing you can do is use contrasting colors to trick the eye into thinking the colors are more saturated than they really are. This means things like making a blue more prominent next to a yellow, which make both of them seem brighter or more saturated. You get idea.

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    Re: Out of gamut colors and color shift

    Make a print and look at it.

    Since gamut isn't affected by print size, you can make an 8x10 or so for evaluation; it need not be poster size.

    - Leigh

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    Re: Out of gamut colors and color shift

    I downloaded the ICC profile from the local printer I am going to use. I want to make sure that I am doing the right thing.
    Here is what i have tried:

    I have noticed a problem with red shifting hue.

    I duplicated the image so that I could view the original and compare it to the proof.

    With the duplicate. I went to the menu view> proof setup>custom> selected the ICC i downloaded from my local printing company.

    This makes the image on the screen show the proof colors.

    I then went into the hue/saturation and adjusted the shifted colors until they look close to the colors of the original.
    However, when I turn off the proof colors and just look at it in sRGB , the reds look oversaturated.

    I am not sure I am doing this right.

    Will it print correctly for the reds?

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    Exclamation Re: Out of gamut colors and color shift

    Quote Originally Posted by Dolce Moda View Post
    Will it print correctly for the reds?
    We can't answer that.

    Make a print and look at it.

    A print will NEVER exactly match the screen image. It's impossible under the laws of physics that exist in our universe.

    - Leigh

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    Re: Out of gamut colors and color shift

    I've been making custom profile for close to a dozen years now and the first thing I do is make a test print with every new profile - to test it and look for any anomalies. Color shifts are usually very slight for out of gamut or saturated colors, but you never know without testing. If this is a print that you are selling, you're going to have to make at least ONE print anyway and see it. The sooner you send it off, the sooner you'll get it back and then you can answer most of your questions through real experience.

    This is also one of the reasons that so many people are making their own high quality and large gamut prints themselves today. If you have your own printer, you could have been through this exercise and learned from your own experience in less time than it takes to... make a print.

    Let us know how it turns out.

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    Re: Out of gamut colors and color shift

    I picked up the photo from the photolab today.

    The printed photo looks very reddish in hue compared to what appears on my monitor for the file. I am not sure if it is the file itself... or the lab screwed it up.

    Maybe I am doing something wrong in my conversion for print. When I prepare a print file, this is what I do:
    1. Convert from 16bit to 8bit.
    2. Convert to profile sRGB (this is what photolabs request as the color space)
    3. Save as jpg

    and when I create webfiles, I go into image size and adjust the dpi to 72 and adjust the size and save it.


    I am growing concerned because a model sent me a link to her page at an agency in Milan and thephotos of her that I took have that reddish look too. I am like WTH... I have been doing my jpgs like this for years and never had an issue.
    My monitor is an expensive one and I calibrate it regularly.

    I asked for it to be color corrected. Maybe that is the problem... the model's skin is supposed to be very pale and now it looks pinky.

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    Re: Out of gamut colors and color shift

    I have come to the conclusion this photolab doesn't know wtf they are doing. I got my second print from them today. It was slightly less reddish than the one yesterday.

    They made me go to the back and look at the monitor in the back and look at my image. The image looked exactly like it does on my calibrated monitior. The guy then went on to tell me that I should have imbedded the the ICC profile as the colorspace in the image instead of using it to soft proof the image.

    I asked him why the print doesn't look like the one on his screen and that was his answer...even though it looks correct on his screen. OMG

    He also said something about I should have provided a sample of how I wanted it to look.
    .... seriously...

    Can anyone recommend an online printer?

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    Re: Out of gamut colors and color shift

    I think you've come to the right conclusion in that these people don't know what they're talking about, however, in order to be fair, you should try one more print and CONVERT the file to their supplied profile and see what happens.

    What should have happened when they received your file and evidently did not was that they should have seen that your file was tagged sRGB and then went on to convert it to their profile and printed it. You should never have a lab do any color correction unless you are intimately familiar with them and know they are up to the task. If you give them an already converted file with the profile embedded they should see it as such and send it on to the printer.

    Just to reiterate: Convert to Profile tries to maintain the look of the file between devices - i.e. your monitor and your print. The look stays the same (or very close) but the pixel values change. Assign Profile alters the look of the file without changing the pixel values at all. One typically uses Assign Profile when encountering untagged files. You assign profiles until you get one that previews the best. There are other more advanced uses, but we'll steer clear of them for now.

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