[Openicc] Is CUPS the right place... (CUPS and ColorSync)

[Leonard Rosenthol]

Just to clarify, Chris - I was talking about during PDF GENERATION.  You are
talking about printing...

Leonard

On Mon, Feb 7, 2011 at 8:01 PM, Chris Murphy <lists at colorremedies.com>wrote:

> On Feb 7, 2011, at 5:51 PM, Leonard Rosenthol wrote:
>
>  If a PDF file contains DeviceRGB or DeviceCMYK objects, ColorSync will
>> change such PDF objects automatically and without warning to ICCbased mainly
>> by embedding e.g. the ColorSync standard profiles in every PDF object
>> (images, vector graphics, text...)
>>
>>
> Apple/Quartz/ColorSync doesn't change anything UNLESS you explicitly ask it
> to.
>
>
> I suppose that's a matter of perspective. If it's a high level, then this
> is not true. Apple/Quartz/ColorSync is an opt-out color management system,
> not opt-in. It will do conversions unless you explicitly tell it not to,
> with one exception and that's /DeviceCMYK to a CMYK device (or PostScript
> file) and in that case it is pass through.
>
> In the case of professional photo printing with RGB output devices like
> inkjet printers, we're constantly getting hosed by Apple's system because
> Adobe products keep having to ask Quartz to do NO MORE CONVERSIONS and yet
> routinely Quartz persists in converting in cases where we don't want it to.
> And a big part of why that happens is because the application correctly sets
> the OutputIntent, but the SPI provided by Apple does not guarantee that all
> objects in the PDF have ICCBased spaces that match the OutputIntent. Because
> of this, Quartz *WILL* do conversions on those objects when there is a
> mismatch between source and destination, even though the application that
> asked for that PDF to be written out with an SPI calling for NO MORE
> CONVERSIONS.
>
> From another perspective, Core Graphics is only doing what it's told to do
> in the PDF. So arguably the PDF is written incorrectly, in that it's going
> to ask for a conversion that we don't want to have happen. And my argument
> has been that if Apple is going to depend on null transforms as the only
> means of disabling ColorSync in the print pipeline, then they need to
> provide a robust API that ensures PDF's written out by Quartz PDFContext
> contain object source profiles that match the OutputIntent.
>
>
> Chris Murphy
>
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