Digital BW, The Print

"Austin Franklin" <darkroom@...> writes:

> > -----Original Message-----
> > From: Moreno Polloni [mailto:mp@...]
> > Sent: Thursday, December 05, 2002 2:03 PM
> > To: DigitalBlackandWhiteThePrint@yahoogroups.com
> > Subject: Re: [Digital BW] Re: Convert to B&W plugins
> >
> >
> > > I still don't understand.  Why can't you get the exact same effect in PS
> > on
> > > a file that is grayscale?  All a filter does is shift/modify
> > the tonality,
> > > and you can easily do that in PS to a grayscale file.
> >
> > It's not the same thing. Shoot a Macbeth colour chart in both colour and
> > B&W. When you scan the colour image in colour, and use the
> > channel mixer in
> > PS to convert to greyscale, you can alter the translation of tonal
> > relationships between the colours, much as you can do with colour filters
> > when shooting B&W film. As the channel mixer is adjusted, the grayscale
> > portion of the Macbeth chart doesn't change much, whereas the tonal
> > placement of colour patches can be drastically changed.
> 
> Moreno,
> 
> It may not be the "same thing" but you certainly can get the EXACT same
> results in your final grayscale output.  You can do manipulation to the
> grayscale data and arrive at the EXACT same resultant output as you can by
> manipulating the RGB data then converting to grayscale.

There are pairs of colors that render identically in (some particular)
B&W emulsion that are different on a color emulsion.  To separate them
in the B&W version, you need to mask them manually.  In the color
version, you can separate them by their color.
-- 
David Dyer-Bennet, dd-b@...  /  http://www.dd-b.net/dd-b/
 John Dyer-Bennet 1915-2002 Memorial Site http://john.dyer-bennet.net
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