Re: [css-gcpm][css-color] device-cmyk() interaction with RGB-space colors.

On Thu, Sep 26, 2013 at 1:21 PM, Rik Cabanier <cabanier@gmail.com> wrote:

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> On Thu, Sep 26, 2013 at 4:35 AM, Henrik Andersson <henke@henke37.cjb.net>wrote:
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>> Rik Cabanier skriver:
>> >
>> > 5. How to handle content that has an RGB only operation (such as a
>> > colormatrix filter) during export to CMYK
>>
>> Wouldn't that particular filter make just as much sense as per channel
>> blend modes? After all, it is a per channel operation. Kinda.
>>
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> not really. Color matrix [1] uses a 4x5 matrix.
> To do the same thing in CMYK, you'd need a 5x6 one.
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> PDF/Adobe allows you to see a colorspace for a blending operation but in
> almost all cases it's the same colorspace as the document.
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>> It would obviously need a dedicated configuration for other color
>> spaces, but the operation itself should make sense.
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>> Question is, has anyone actually tried using a color matrix on anything
>> besides RGB? Not counting shenanigans to setup the matrix to convert to
>> rgb before the main effect...
>>
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> I'm not sure. I could ask our PhotoShop people.
>

FYI Photoshop's channel mixer can apply a color matrix to CMYK data.