CMYK Colour Problems

Discuss QuarkXPress color management functionality including DeviceN workflows

CMYK Colour Problems

Postby Hannaht » 01 Sep 2004, 04:52

Hi,
I am using Windows 2000 Professional with Quark 6.1 and Adobe Photoshop CS.
When I am creating documents and inserting digital photographs which I have edited in Photoshop, or inserted straight the colours are wrong.
I change the photographs to CMYK in photoshop and insert them, when I view them in Quark or print them off from Quark the colours are very yellow, I manually have to adjust the colour levels on every picture.

If I insert an RGB image there is no problem with the colours.
Please can someone suggest if there is something I can do so I don't have to adjust every picture.

Thanks
Hannah
Hannaht
 
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CMYK Colour Problems

Postby Tom Owens » 01 Sep 2004, 07:27

It sounds like your color space in Photoshop is wrong, or you are using color profiles that aren't correct.

I'm betting it's your Photoshop color space. Check that out in the color settings and see what it's set to. Also, make sure you're not embedding a color profile in your images when you save them.

Regards,
Tom
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CMYK Colour Problems

Postby Hannaht » 01 Sep 2004, 07:55

Hi Tom,

The colour settings are North America General Purpose Defaults and the working space colour CMYK setting is: US Web Coated (SWOP) V2.

I am guessing that these were default settings when Photoshop was installed as I have never changed then.

I am sure that I am not embedding any colour profiles when I save them so I can rule that out as a course of the problem.

Thanks
Hannah
Hannaht
 
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CMYK Colour Problems

Postby Tom Owens » 01 Sep 2004, 08:10

Well, that blows that out of the water. It isn't photoshop. It would be interesting to see one of those pictures. Unless you assign a color profile to an image, Quark doesn't change anything.

The fact that the image displays very yellow in Quark but not in Photoshop is mysterious.

Regards,
Tom

p.s. Have you run Adobe Gamma on your monitor? Maybe it's as simple as that...your display is a bit off, so your image looks fine until Quark gets it.
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CMYK Colour Problems

Postby wasabi » 01 Sep 2004, 08:17

It is difficult to judge color from a monitor. It displays in RGB no matter what. Therefore, it doesn't depict CMYK very well. You can calibrate it to get closer to accurate color. How do the photos print straight out of Photoshop? I expect not any different. What kind of output device are you using?

Bottom line: go by the numbers. If yellow is out of balance in the neutral areas of a photo, that indicates a color cast. It may be originating from your scanner. Try a piece from an alternative source, such as stock art. Note the comparison, both in the way it prints and the balance in neutral areas. Not that stock art won't have color cast, just likely a different one.
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CMYK Colour Problems

Postby Hannaht » 01 Sep 2004, 08:47

The photos print straight out of Photoshop fine and as you guessed there is no difference with the colours. I am using an OKI C9400 colour lazer jet CMYK printer

The photos which I am using are straight from Digital cameras, mostly from a Nikon D100 I think, but I don't take the pictures, I think they sometimes have a colour profile with them but not always. The problem is it seems to be any picture from a variety of sources which look yellow.
Hannaht
 
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CMYK Colour Problems

Postby Tom Owens » 01 Sep 2004, 08:57

Give this a go:

1.Activate a picture box and choose File ? Get Picture.
2.Select the picture you want to import. The default selection in the Profile pop-up menu uses the profile specified in the Color Management Preferences dialog box. For example, the Profile pop-up menu setting for a CMYK TIFF defaults to the selection in the Profile pop-up menu for a CMYK picture (Edit ? Preferences ? Color Management ? CMYK tab ? Images area).
3.Choose a profile from the Profile pop-up menu that matches the device from which the picture was scanned. If the picture was edited, assigned an ICC profile, and saved using an image-editing application, choose the assigned profile if it still corresponds with the device on which the picture will be output.
4.The Color Manage to RGB Destinations check box changes to Color Manage to CMYK Destinations when you are importing a CMYK picture. Uncheck Color Manage to RGB Destinations or Color Manage to CMYK Destinations if you dont want QuarkCMS to apply color management when the destination color space is the same as the image color space; then click Open.

It's worth a shot.

Regards,
Tom
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CMYK Colour Problems

Postby rich » 13 Sep 2004, 11:16

Hannah and moosh,

This is a bummer - I wrote this long dissertation this morning and it apparently it didn't post.

First, the reason that eps's and tiff's are coming out different is that Quark cannot color manage eps's (vector or raster). If the eps's are printing out of Quark how you want, then pull the Quark CMS Xtension. This indicates that Quark is performing some kind of unwanted color transformation.

If you are getting appropriate output from Photoshop then you've got to look at the output settings between the two programs. You cannot turn off color management in Photoshop anymore (I know - it has the Turn Color Management Off preset - but if you look at the documentation it states that assumptions are still being made about your file). Also, worth noting that the two programs are using different color management engine. Quark is using ColorSync (and therefore, most likely, the AppleCMM ((Color Management Module))). Photoshop is, by default, using the Adobe Color Engine (ACE).

If RGB images are printing appropriately, but CMYK are not, then something else is going on in the PPD. Are you printing RGB or CMYK (in your Output tab)? The driver for your output device may be configured to handle RGB. You can test this by printing out 2 blocks on the same page - one black the other Registration (print the page CMYK). They should look noticably different on the printed page. If they are not - then your printer is converting your CMYK data to RGB.

Now, what is happening with Color Management? Be careful what you ask, moosh, 'cause this is one of my favorite topics and I will talk ad nauseum.

In a nutshell color management is:

Taking the data in a file, mapping it to a device-independent color space and then mapping into the color space of the output device. So:

Nikon D100 > CIELab > Okidata C5400

to use the example specified earlier in the thread.

In the original file from the D100 we can take the color specified by the RGB numbers 255, 0, 0 (red, right?) into Lab. In CIELab it maps to 54, 75, 69 (the same RGB numbers from a different device will map to different Lab coordinates ). Then from CIELab to your printer - the color will map to some CMYK like 0, 88, 83, 0 (the same Lab coordinates will map to different CMYK values when going to a different output device).

RGB and CMYK are device-dependent. This means that they are dependent on the input or output device. As an example, the same color red will look different printed to different printers. CIELab is device-independent. It is based on observations of color vision and is not associated with any input or output device. CIELab is constant.

Some references:

GATF Color Manangement Conference in Scottsdale, AZ December 4-7.

Understanding Color Management by Dr. Abhay Sharma
Real World Color Management by Fraser, Murphy, and Bunting

Feel free to contact me off-list.
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CMYK Colour Problems

Postby rich » 17 Sep 2004, 07:44

[strong]moosh:[/strong].

Everyday I'm learning something new

Aint it the truth!
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CMYK Colour Problems

Postby Hannaht » 20 Sep 2004, 03:00

Thanks for all your advice, I am currently still having problems with my colours, I think that I might have an embeded colour profile in my digital photos, so I am currently trying to sort out having some pictures without that to see what results I get.

I am also having some problems with coloured shapes inserted into Quark these are saved as Tif files and they also change colour.

I am currently waiting to get a new monitor for work and when I have set that up I am going to try and sort out my colours. I think that I will end up reinstalling my programs and see what happens as at the moment my IT department do that and I have no control over the install.

Anyway thanks for your help, if anyone else has any fantastic ideas which I can try I would appreciate them
Thanks again
Hannah
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