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The new Preflight module built into Acrobat 6.0  Professional (as well as
its sibling pdfInspektor2 from callas software) will list for every page
on how many pages it is going to put marks. The underlying assumption is
that the process color model is CMYK, i.e. Device RGB as well as any
calibrated color spaces (ICC based, Lab, CalGray, CalRGB) are considered
to always image on all four CMYK plates. With regard to DeviceMYK the
decision is made based on the tint values used in each channel.
DeviceGray and Separation Black are considered to print on the Black
plate only. "All" (registration color) never prints a plate by itself.
Images are considered to use all of their color channels (even if for
example you have a DeviceCYMK image that only happens to use values other
than zero on the black channel). And finally - the Black plate is
considered to be used as soon as any object in DeviceGray, DeviceRGB,
DeviceCMYK, calibrated color spaces and All is used, even if any such
objects happens to paint only 'white'.

This works very well for practical use in prepress towards all the common
printing processes (which usually follow he CMYK process color model,
plus spot colors, whether on their own, in conjunction with a Black
plate, or with all 4 CMYK plates).

When dealing with RGB oriented files or devices, this may fail to report
that a page is pretty much black only. But then, on RGB devices you do
not have a black plate or separation anyway. If it is relevant to deal
with RGB files with regard to differentiating between black only pages as
opposed to pages 'really' using color, the best approach is to use color
RGB conversion features in Quite A Box Of Tricks (www.quite.com),
SuperColor  (www.heidelberg.com) or PDFenhancer (www.apago.com). These
tools have options to convert RGB to Black/grayscale if the values for R,
G and B are equal (does not apply though to pixels inside an image).

Olaf Druemmer


PS: You could even use the free "PDF/X-3 Inspector (Freeware)" - see
www.pdfx.info for a download - to find out the same information.

[EMAIL PROTECTED] wrote Fri, 10 Oct 2003 07:46:32 -0400
>At 2:18 PM +1000 10/10/03, John Weichard wrote:
>>Does anyone know of an application that will interrogate a multi 
>>page PDF and report on the number of colour and B&W pages contained 
>>in the document?
>>
>
>       There are programs that can tell you about the colors being 
>used, but not specifically if a page is "color" vs "B&W" since the 
>definition of each isn't as cut and dried in publishing.
>
>       For example, if the PDF specifies "black" in RGB or CMYK - is 
>that Black to you?  What about the spot color "All" - is that White?
>
>
>Leonard



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