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

On Fri, Sep 13, 2013 at 4:57 AM, Chris Lilley <chris@w3.org> wrote:

> Hello Rik,
>
> Friday, September 13, 2013, 4:33:46 AM, you wrote:
> > On Thu, Sep 12, 2013 at 5:31 PM, Tab Atkins Jr. <jackalmage@gmail.com>
> wrote:
> >
> >>  That would be a device-independent profile, which obviously goes
> >>  against the apparent point of the function
>
> > Not sure if I follow. When you print, you will use the profile of the
> device.
>
> No, the point of device colour is that there is no processing. You
> don't attach a colour profile to the device CMYK and then colour
> manage it (which might change the values).
>

I think we're saying the same thing.
In a CMS workflow in the Adobe applications, we tag all content with
profiles. If during printing the profile of the element matches the output
profile, no conversion is necessary and the colors are passed along as-is.


>
> > The CMYK values will be used as-is since they are assumed to be in
> > the colorspace of the device (hence device-cmyk).
>
> Yes, they will be used as-is.
>
> > RGB is always in sRGB so you will go from sRGB to device dependent CMYK
>
> No, RGB is not necessarily sRGB. But yes, if you have colour in some
> calibrated RGB space and are outputting on some calibrated CMYK
> device, you will go from your RGB profile to the PCS to the target
> CMYK.
>
>
> --
> Best regards,
>  Chris                            mailto:chris@w3.org
>
>