Prepressforums.com

jee · #1 (**permalink**) 07-05-2007, 12:52 AM

I've recently upgraded my computer, upgraded to Photoshop CS2 from much older version, and also changed printing company, so I don't know what's causing the problem, but here is the issue I'm having.

I used to be able to view the color change when I converted an RGB file into CMYK. I know it wasn't an exact display of what the output should look like but it gave me a good idea of which colors to edit before sending the file to press. But I'm no longer able to view any color change from RGB to CMYK anymore, and here is what happened.

After converting to CMYK, I didn't see any change, so assuming that I don't have to edit colors, I sent the files to the new printing company. I never really order press proof, since the job is so small, and I received the digital proof, which looked just like the file I sent them, so I approved it.
Well, the product I received had horrible dark yellow green cast all over it, and the printing company claims that it's not a color shift and the outcome matches the PMS info of the file that I've submitted.

I'm pretty much stuck with boxes of postcards that are of no use. We sell high-end luxury fabrics, and the quality of color on our marketing materials are so critical.

I don't think it's a monitor calibration problem either. I went on line to order a set of digital prints of before and after converting to CMYK, and after uploading two, I was able to view the RGB file, which looked great, and the CMYK file with the yellow-green cast just like the postcards that I got.

Why is it that I'm not able to view the difference between CMYK and RGB at all in Photoshop? Had I know that there is baby poop green all over the image, I would have removed them.

Any Ideas???

Techboy · #2 (**permalink**) 07-05-2007, 05:01 AM

If I remember correctly, you need to have the gamut option turn on in Photoshop or else you won't be able to see the color shift when converting from RGB to CMYK.

Also you can also quickly check your histogram/level after conversion to see if any of the color channels are out of range.

Hope this helps.

jee · #3 (**permalink**) 07-05-2007, 10:37 AM

Thank you for your reply.

I turned the gamut warning on, but still no difference in display of color before and after converting. However, the histogram shows a dramatic shift.

I would still like to be able to see the shift in color, but it just isn't happening... :cry:

born2print · #4 (**permalink**) 07-05-2007, 12:06 PM

Unable to reproduce (in CS3)
I see the shift immediately...

any more clues?
are you sure it's not shifting? some colors may not change much, I tested by making an RGB file filled with the RGB-est looking bright blue there is, then switched mode to CMYK.

jee · #5 (**permalink**) 07-05-2007, 12:38 PM

I know for sure it's shifting. It's just not displaying it.

I used to be able to see the shift right away, too, and get real disappointed at CMYK colors and all that good stuff....

Thanks for taking the time to test it out for me though.

It is a big encouragement.

Greg_OneVision · #6 (**permalink**) 07-05-2007, 01:37 PM

Just out of curiousity, what are your photoshop color settings? If you upgraded from an older version, the new defaults might be different.

What type of digital proof did they send? PDF? If so, what are the color values in the PDF and how do they compare to your expected color values?

Regards,
Greg

born2print · #7 (**permalink**) 07-05-2007, 01:37 PM

Yep, just sorry we couldn't figure it out though! :?

jee · #8 (**permalink**) 07-05-2007, 02:20 PM

Here is what I see when I open the color settings dialog.

Settings: North America General Purpose 2

Working Space:
RGB: sRGB IEC61966-2.1
CMYK: U.S. Web Coated (SWOP) v2
Gray: Dot Gain 20%
Spot: Dot Gain 20%

Color Management Policies:
Preserve Embeded Profiles for RGB, CMYK and Gray

I'm not too familiar with color settings and management...

ops:

The digital proof I got wasn't a PDF file. They uploaded the proof on their website and e-mailed me a link to it. The color looked just like the CMYK file I sent them, but the actual postcard doesn't look anything like the proof that I approved. I suppose I should have at least asked for a high-res laser print out.

mrseang · #9 (**permalink**) 07-05-2007, 03:02 PM

First off...I'd ask why their proof does not match their lazer print??
It should not be that out of wack...don't let um give you shift bs.

Also, the PDF proof is a great idea. Different program. You should be able to open the photoshop file side by side with Acrobat and the pdf. Then you should be able to see if their is some kinda shift. PDF proofs are a standard, they should not have an issues sending you one.

Also, print to your inkjet just to check it out. Just a few ideas.
I've never had the issue with photoshop you talk about.

Greg_OneVision · #10 (**permalink**) 07-06-2007, 05:11 AM

Jee

Those color settings are all pretty standard.They are the web defaults. You may at some point want to swtich those to to North American Prepress. Basically, your sRGB changes to Adobe 1998.

I agree with Mrseang here. There shouldn't be a huge shift. And if there is, just maybe the printer is trying to pull a fast one on you. Do you have the actual file you could email me or post for us to look at. And provide a detailed description of where the color shift is?

The link to the proof might be handy as well.

Regards,
Greg