Proof Color & RGB in Photoshop

H

Halflap

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Name
Steve
Edit My Images
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Been playing with printer profiles in Photoshop CS5 and I am confused.

I have a file that has the sRGB profile assigned. If I set up a custom proof condition as directed by my print lab I see a change in the colours when I turn on proof colors. This is expected.

If I set up a custom proof condition as sRGB the colours still change when going into proof colors.

Why?
 
Not sure about your terminology. You say the file has sRGB assigned to it. Do you mean that the file is an sRGB file or you have simply assigned the profile by going to the EDIT >assign profile. If so all this has done is change the profile "tag" in the image file to sRGB it hasn't converted it to sRGB colour space. This may be why you are seeing a difference

I've just done a simple test and I find that there is no change if I proof the image in the colour space it's working in, either in sRGB or Adobe RGB
 
Are you trying acheive more accurate output results?

If so i'm not sure setting up your own custom profile is a great idea as it may conflict with the profile used by the print lab? Maybe see if they can supply a copy of their profile?
 
Thanks for the reply Chappers. Your tests confirmed what I was expecting to happen on my PC.

My camera is set to sRGB and RAW files. The RAW file is loaded into Photoshop and saved out as a jpg.

If I open the jpg and choose EDIT--> Convert to Profile the Source Space is set to sRGB IEC61966-2.1. If I set up a custom proof condition and use sRGB IEC61966-2.1 as the device to simulate I am getting a noticable warming of the colours when switching to proof colors. I have tried ticking / unticking preserve RGB numbers and black point compensation but this makes no difference.

The RAW file loaded into Photoshop does the same.

I tried converting the jpg to Adobe RGB (1998) and creating a custom proof condition and the image gets darker when in proof colors.

I am confused. I set up the color settings as directed by my print lab. My screen is calibrated. There must be a setting somewhere that is causing this but I can't find it.
 
Look in this menu:

view --> proof setup menu

I think you may have working CMYK selected.

This will in most cases change shades ect..


......


Does the output print look okay or do you have a variance?
 
Sounds really weird.

Try this.

Ignore the sRGB file and work on the RAW file.

Open the RAW file in ACR. Check that the parameters are set to save as sRGB. The info should be under the main image window. If it's not click on the data line which should the allow you to change the colour space. Now save the image.

Repeat the soft proofing as you have done already. If you get no real difference then I suspect the problem is with the colour space that the camera is attaching to the jpeg.

If you still get a difference then something really weird is happening
 
Thanks for the suggestions

Arcon5
I have made sure that the proof settings are set to match the profile of the file (either sRGB or Adobe RGB). I have the icc profile from my lab but was just checking things expecting that if the proof settings were set to emulate the profile of the file then changing to proof colors should have no effect on the screen image. As this is not the case I am wondering if the profile supplied by the lab will show the correct colors.

Chappers
I opened one of the RAW files from Bridge into Camera RAW. The setting were to use Adobe RGB (1998) so for simplicity I left it. On opening into Photoshop I took a screen shot and then changed the proof setting to Adobe RGB (1998). I then took another screen shot. The results are below. As you can see there is a noticable difference between the two grabs. All I did between these two grabs was press CTRL-Y to turn on proof colors. I think I will look into backing up Photoshop's Preferences and resetting to defaults.

5401569748_b420d82886_b.jpg
 
Now for the real weirdness.

I have deleted the preferences and restarted Photoshop. No change.

So as a test I opened a jpg with sRGB IEC61966-2.1 colour space.

Go into Convert to profile and the Source space shows sRGB IEC61966-2.1 as expected. Change Destination space to sRGB IEC61966-2.1 as well and the image changes as I check and uncheck the preview box.

If I apply this it still changes when I change to proof settings.

I GIVE UP.
 
Try this

Convert to profile and convert to sRGB IE61996-2.1. Don't worry if the colour changes. Save the converted image.

Now soft proof this image and see what happens.

Another off the wall idea. Select sRGB as your monitor profile, and see if you get a change when you soft proof the "original " image and the converted one. Don't forget to reset it after the test.
 
Chappers

Tried converting and saving and this mede no difference.

Then tried changing the monitor to use sRGB in Display settings. As I have 2 monitors I only changed one. If I put Photoshop on the display that has sRGB profile the colours do not change (Hooray). If I move Photoshop to the other monitor. The problem comes back.

Spot on and thanks for the perseverance. I now understand why it is doing that and I can trust the icc profile that I downloaded from the lab.

swanseamale47
I am sending the prints off to a lab and had downloaded the icc profile for their Fuji printer and set up color settings as described on their web site. The problem was that I then tried to set the working profile and the proof profile to sRGB which I assumed would give me the same colours. When this was not the case I was concerned that there was something wrong with my setup. By setting the monitor to use the sRGB profile the problem is resolved.

I think this means that the profile I created with my Huey Pro calibrator is not 100% accurate so I will need to look into this. May be the excuse I need to buy some nice new monitors.

Many thanks to all who helped.
 
If I set up a custom proof condition as sRGB the colours still change when going into proof colors. Why?
Click to expand...
- This is because PS can not directly convert from one colour space to another, so it uses the LAB space as a bridge for conversion.
In effect you are proof previewing an sRGB->LAB->sRGB image and hence seeing differences.

Go into Convert to profile and the Source space shows sRGB IEC61966-2.1 as expected. Change Destination space to sRGB IEC61966-2.1 as well and the image changes as I check and uncheck the preview box.
Click to expand...
- here in the preview window you are seeing the above conversion, however when you click ok it will not convert (as there is nothing to change). So you are back to square one when you do the proof view.

In essence you cant use the same colour space to validate that all well with proofing.
The proof view is great for sorting out the out of gamet colour problems and giving a general idea of how the image will print but it is only a general idea. The only real way to check it is to print it.

Hope this helps.
 
Thanks kappa, nicely explained.

Up until now I have been letting the lab colour correct the images but I feel I want more control. This is why I have been trying to get my head around colour management. I sometimes wish I had never started.
 
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