Color-shifts: PS vs InDesign PDFs

[Kirstens@cre8.com]

We are using CS4 Creative Suite (MacOSX)

In PhotoShop (PS), we have a standard agency color profile, that is setup in color settings. All our images use this setting, which has worked great. I have recently noticed some inconsistencies when PDFs and JPGs are made from InDesign. After checking around, I noticed that some people had the default settings of Northern America prepress2, so we were all looking at something different. So IT went and changed everyone to the same color settings (same as PS).

Here is my conundrum:
I make a LR PDF (smallest file size, which defaults to the output setting: Color Conv.: Convert to Destination and Destination: sRGB IEC61966-2.1), and then
I make a HR PDF (Pressquality, with the output settings changed to: Color Conv: Convert to Destination (preserve numbers) and Destination to our color profile which is used in our image conversion and workspace.
Okay I've made these two PDFs, and when I open them, the color of the LR PDF matches the original PS (image)/InDesign document, but it does not match the HR PDF. If I export to JPG, it also matches. If I go into my HR PDF output settings and change the destination to RGB (message comes up saying, document's transparency blend space doesn't match the destination color space....), however, the final PDF matches my original PS image. I’m very confused.

Not sure if I'm explaining this legibly, but my end result needs to be that my HR PDF matches my Photoshop file. Am I missing something obvious in this? I have made different scenerio PDFs, but the only on that made a difference is the destination of my PDF output to RGB, but I need it to be CMYK, and to match my image file.

Does anyone have any ideas?
Thanks in advance!
KS :-)

[Lukas Engqvist]

What is the conversion mode perceptual or relative (with or without black point compensation).
Are you saving the images from PS in RGB or CMYK?
What is your transparency blend space in InDesign?

I would draw a flow chart of my work flow and see whet colour conversions and profiles are active at which stage.

When you checked all the settings are the same did you have the settings in advanced mode so that you got all the settings? Are you warning when profiles differ? Are you choosing ENABLE ALL PROFILES for RGB and IGNORING ALL PROFILES for CMYK? (if you are honouring CMYK you may be enabling an old CMYK profile rather than the new settings)

Trouble shooting colour isn't easy and needs to be done one step at a time.

[Stephen Marsh]

Is this a trick question or am I missing something obvious here?

I presume that the original image is RGB? What RGB (sRGB, Adobe RGB etc)...

Your low res image PDF is in sRGB, the same colour mode (if not space) as the original image?

Your high res image PDF is in CMYK (different mode and different colour space).

There is obviously a gamut issue with the destination mode (CMYK), compared to the original image mode (RGB). This is not unexpected.

Convert your low res PDF to CMYK, or leave it as sRGB and use say PDF/X with a CMYK output intent. Now the low res should be the same colour as the high res. You could even make the low res PDF CMYK and then sRGB if the CMYK ICC profile is going to bloat the PDF file size too much.

Due to the differences in RGB and CMYK, it may not be possible for the high res CMYK image to appear the same as the RGB Photoshop original.


Stephen Marsh

[michaelejahn]

We are using CS4 Creative Suite (MacOSX)
Here is my conundrum:
I make a LR PDF (smallest file size, which defaults to the output setting: Color Conv.: Convert to Destination and Destination: sRGB IEC61966-2.1), and then
I make a HR PDF (Pressquality, with the output settings changed to: Color Conv: Convert to Destination (preserve numbers) and Destination to our color profile which is used in our image conversion and workspace.
KS :-)

So, the issue is that you are thinking that an image saves as RGB with an sRGB profile should look like a CMYK image with GRACoL or FOGRA39 output intent ?

That will never work - your LR and HR must both be the same color space and have the same profiles for the CMM to render them identically.

Hope this helps.

Perhaps this example file might help you get your head around why your assumption is incorrect;

http://support.composeusa.com/webfil...RGB_GRACoL.pdf

One can have a single image - placed multiple times - in a single PDF - display and print quite differently depending on the images profile.

[Lukas Engqvist]

@Stephen M and Michael J. To assume that it is not possible to display the same on screen between RGB and CMYK I think is a bit strong. There are large areas of overlap, and many colours can be simulated on screen. If this were not so the idea of soft proofing would be preposterous. Now there are some colours that do not overlap, but I doubt if that is what is being explained. It is much more probable that there are 2 or more RGB profiles and 2 or more CMYK profiles that are crisscrossed in a colour management knot as opposed to a flow.

[rich apollo]

To get them to match the low-res profile, the RGB elements will have to convert to the CMYK colorspace and then to the RGB colorspace. This used to be called a "simulation profile". Try outputting hi-res PDFs and then converting those into lower-resolution proofing PDFs.

[Stephen Marsh]

@Stephen M and Michael J. To assume that it is not possible to display the same on screen between RGB and CMYK I think is a bit strong.

That is not what I am saying Lukas. I did not say that it was generally not possible. It should be noted that I offered the possibility using an PDF/X CMYK Output Intent with RGB images or of converting the low res PDF images to CMYK and then back to sRGB (which could clip more saturated yellows or cyans).

We don't know the original RGB image colour space (sRGB, Adobe RGB, ECI RGB, ProPhoto RGB, Wide Gamut RGB etc) and what is being clipped to sRGB.

We don't know the colour values in the file, if the colour numbers push the gamut beyond what is possible in the CMYK destination (I am assuming they do).

We don't even know the CMYK colour space or the rendering intent (something like F39, newsprint etc).

What we do know is that the OP is having colour differences. We have been told that all users are now "synced" with the same colour settings, however there is a colour difference between the master (RGB?) image/low res PDF and the final press ready CMYK image. It could indeed be crossed up colour profiles as you suggest.

I am not saying that it is impossible to display an RGB image and a CMYK image with similar appearance. Without knowing the image modes, image colour spaces and image colour values - my first assumption is that this is simply due to the expected colour gamut differences between RGB and CMYK. This is an assumption, I don't have much to work with here! Yes, I am assuming a worst case scenario - for all I know the image is made up of lots of blues and oranges which are being hammered when one compares the RGB to CMYK result.

Regards,

Stephen Marsh

[michaelejahn]

@Stephen M and Michael J. To assume that it is not possible to display the same on screen between RGB and CMYK I think is a bit strong.

Hey Lukas.

Okay, so you have a page. It has a few images in it. You want to create a LR version of the HR version. I really do not care if the HR version is made of up RGB images with sRGB embedded profiles or CMYK images with GRACoLprofile - or even a combination of both.

my point was simply that if you want the LR and HR versions to to look the same color wise, why not just downsample and keep all the color the same for the LR ? I mean, how is Convert to Destination and Destination: sRGB IEC61966-2.1 going to help here ?

This is not some color contortionist skills exhibition contest to prove someone can do something exotic - the OP ask what they were doing wrong, and that is what they are doing wrong. They stop doing that, the problem goes away, and we move onto the next thread, as this one is answered, yes ?

Why suggest something wacky that the OP already knows does not work ?

If you have a CMYK page that is simple to process into Convert to Destination and Destination: sRGB IEC61966-2.1 and it displays just like that CMYK HR original, please post it.

tap tap tap - that is the sound of my foot tapping as I wait !

( wink )

[leonardr]

The other thing that folks here are overlooking is that if your colors in the output PDF are DEVICE (untagged) colors, then Acrobat is free to choose whatever profile it wants to display them (which is really whatever you had your color settings chosen as, but still).

If you WANT to ensure the correct colors being used, then PLEASE make PDF/X compliant files. By specifying the OutputIntent, you ensure that that profile will be used when rendering and thus guarantee accurate and consistent color.

[michaelejahn]

@ Leonardr - 15 tips of the hat you for remembering to include the PDF/X part - since I always as as PDF/X-4 when exchanging a file with another party, I always assume that we all understand that - I should have said that explicitly. Even LR files should have an output intent, and yes, the output intent needs to match the HR.