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CMYK channel mixer problems..

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  #1  
Old 01-25-2007, 08:17 PM
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CMYK channel mixer problems..

Hi,can anyone help? Thks thks.
I usually convert to B/W for RGB using channel mixer, which works great.

But when I work in cmyk, using channel mixer to convert seems to give it a very 'washed out' look. My image must remain in CMYK mode but grayscale.
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Old 01-25-2007, 08:46 PM
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Re: CMYK channel mixer problems..

Saberlancer, why don't you just bring the image into RGB or LAB first. Use one of the 10 methods to convert to grayscale and when you are done convert the image back to CMYK?
Regards, Murray
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Old 01-25-2007, 08:53 PM
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Re: CMYK channel mixer problems..

Thks Murray,
Well thats one alternative I've been using..
Just wondering if there's a way to retain the channel mixer layer and just show/hide.

Any reason why it works so much better in RGB than CMYK?
I mean the channel mixer method to adjust/convert to B/w.
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Old 01-25-2007, 11:10 PM
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Re: CMYK channel mixer problems..

saberlancer,

i'm no coder, but color mixer seems to have been made pretty much for rgb mode. i mean, even the sliders are labeled red, green and blue.

why not use hue/saturation? you can simply move the saturation slider all the way to the bottom. this removes all the color but keeps you in 8 bit color mode.
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Old 01-26-2007, 01:26 AM
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Re: CMYK channel mixer problems..

Quote:
Originally Posted by Kraellin
saberlancer,

i'm no coder, but color mixer seems to have been made pretty much for rgb mode. i mean, even the sliders are labeled red, green and blue.

why not use hue/saturation? you can simply move the saturation slider all the way to the bottom. this removes all the color but keeps you in 8 bit color mode.
Hi Kraellin, actually the channel mixer in cmyk files are CMY&K.
Another question is that when I use saturation to 0%,my file appear 'reddish'..why?

Again this is only for CMYK, RGB is fine..

Help...
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Old 01-26-2007, 01:37 AM
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Re: CMYK channel mixer problems..

In CMYK mode you are working with channels, that are build according to a certain printing process. Structure of every channel is very much depends on CMYK profile. Sometimes it is impossible to build nice structure, only mixing channels. Go with Lab, it is better.
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Old 01-26-2007, 02:20 AM
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Re: CMYK channel mixer problems..

Quote:
Originally Posted by OnAir
In CMYK mode you are working with channels, that are build according to a certain printing process. Structure of every channel is very much depends on CMYK profile. Sometimes it is impossible to build nice structure, only mixing channels. Go with Lab, it is better.
I've considered LAB.
But my stuff go to print CMYK. So if I work in LAB, then convert to CMYK,there'll be color shift right?

Does any DI/retouchers here use LAB?How to control color shifts issues?
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Old 01-26-2007, 05:14 AM
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Re: CMYK channel mixer problems..

When speaking about grayscale conversion via Lab, I meant, that you need to convert your image to Lab, then desaturate, usually add some contrast and after convert to grayscale or CMYK with your printing profile.
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  #9  
Old 01-26-2007, 09:18 AM
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Re: CMYK channel mixer problems..

For B&W, it is standard practice to use Quadtone.
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Old 01-26-2007, 10:50 AM
KR1156 KR1156 is offline
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Re: CMYK channel mixer problems..

what colors do you normally set for your quadtones?

maybe it varys for the feel your going for, cool, warm etc.?

or do you mean you get the tonal values that you like using quadtne colors, then convert to grayscale?
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