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Newb: out of gamut colors and color shift

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  #1  
Old 01-15-2011, 12:19 AM
5nap5hot 5nap5hot is offline
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Newb: 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 checked the gamut warning and have seen that there are some problem spots.

I am pretty new to using this feature of PS so 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 on an unmodified jpg and noticed the lips went from a fuschia color to burgundy.

Is there a way to prevent the color shift and keep nice saturation?

Last edited by 5nap5hot; 01-15-2011 at 01:50 AM.
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  #2  
Old 01-15-2011, 03:16 AM
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Repairman Repairman is offline
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Re: Newb: out of gamut colors and color shift

Open up the file in PS. Go to Mode and switch to CMYK. Toggle between the RGB and CMYK image and you will see instantly where the "illegal" colours are. Normally vibrant colours will appear dirty (eg the yellow/white glow around a lamp). Bright blues will become dull or too red. CMYK is an ink process and does not have a brightness control. How do you make bright blue from cyan and magenta? Try retouching the problem areas after converting the file to CMYK or, make a copy, retouch in CMYK, convert to RGB and patch these areas in to your RGB file. If you aren't comfortable in CMYK, you should speak to the printer because a lot depends on his set up. Speak to him anyway.
R.
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Old 01-15-2011, 03:07 PM
5nap5hot 5nap5hot is offline
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Re: Newb: 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.


My local printing company wants the files in sRGB.

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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Old 01-15-2011, 03:08 PM
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andrewrodney andrewrodney is offline
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Re: Newb: out of gamut colors and color shift

The gamut warning is pretty useless! Its legacy functionality from Photoshop prior to version 5 which uses ICC profiles to map the out of gamut colors into gamut using various rendering intents. The idea in the old days was to put the warning on, then brush the overlay colors with a desaturation brush to get those colors “into gamut” which is now done with profiles upon conversion in a far more robust, accurate and faster way. Plus the gamut warning is based on the current customize soft proof setup (so its important to set that if you really must use this old legacy approach to seeing out of gamut colors). Use good ICC output profiles and convert with them, using a rendering intent based on the appearance you prefer, the gamut mapping (out of gamut to in gamut) will be taken care of upon conversion.
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Old 01-15-2011, 04:42 PM
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Re: Newb: out of gamut colors and color shift

Viewing proof colours on screen? I have a Barco 28inch colour calibrator monitor and it's no match for a hard copy in the hands! The reason you speak to your printer up front is that it's his fault when it goes wrong. (Only half joking BTW)
R.
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Old 01-15-2011, 07:27 PM
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holgaman holgaman is offline
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Re: Newb: out of gamut colors and color shift

5nap5hot,
Most likely, the ICC profile you got from the printer was meant for CMYK, since those are the colors they will be printing with. I'm not sure how accurate it would be to apply that to an RGB photo. Did they say why they wanted the photo in sRGB rather than CMYK?
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Old 01-15-2011, 10:24 PM
5nap5hot 5nap5hot is offline
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Re: Newb: out of gamut colors and color shift

Quote:
Originally Posted by holgaman View Post
5nap5hot,
Most likely, the ICC profile you got from the printer was meant for CMYK, since those are the colors they will be printing with. I'm not sure how accurate it would be to apply that to an RGB photo. Did they say why they wanted the photo in sRGB rather than CMYK?
They do all their printing on a Noritsu LPS-24 PRO. It will accept only rgb files
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Old 01-15-2011, 11:39 PM
pixelzombie pixelzombie is offline
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Re: Newb: out of gamut colors and color shift

not familiar with the device but it appears to be a true photographic output unit, your #3 post is how i usually use soft proofing but i won't try to match them exactly, i will just try to get closer to the "original"
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Old 01-16-2011, 09:37 AM
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Markzebra Markzebra is offline
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Misinformation Warning

Quote:
The gamut warning is pretty useless! Its legacy functionality from Photoshop prior to version 5
Thats not true. It's not useless, and certainly not outdated at all. If you are retouching using Adobe RGB, or even more worryingly Pro-photo RGB, then you will certainly need to get some idea of what you are doing using Gamut Warning and Proof colors. Because in only this way can you get an idea whether you are producing colors in your retouch that are severely out of gamut. Since there is no rendering intent (Relative or Perceptual) that will do this perfectly, it would be extremely unwise to ignore this. If you care about color, and your intention is to produce an image with saturated colors, you would almost certainly end up with a highly damaged result if you ignore this.

These warnings and previews change depending on what you have set up in your Color Settings. So they are very useful, not a dumb process, and are certainly not out of date. And they came in along with the rendering intents, one didn't supersede the other.
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Old 01-16-2011, 12:24 PM
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andrewrodney andrewrodney is offline
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Re: Newb: out of gamut colors and color shift

Quote:
Originally Posted by 5nap5hot View Post
They do all their printing on a Noritsu LPS-24 PRO. It will accept only rgb files
And you could get an RGB ICC profile (I’ve built em, they can exist).

The gamut of such devices isn’t all that wide FWIW.
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