Digital BW, The Print

> From: DigitalBlackandWhiteThePrint@yahoogroups.com
> Reply-To: DigitalBlackandWhiteThePrint@yahoogroups.com
> Date: 2 Dec 2002 22:26:32 -0000
> To: DigitalBlackandWhiteThePrint@yahoogroups.com
> Subject: [Digital BW] Digest Number 1160
> 
> Keith,
> 
> If it merely used the green channel, it would be losing information.
> Typically, scanners that scan B&W in RGB, of which is %99.999999 of them,
> they scan in RGB and use some precanned "mix".  This mix is based on someone
> else's opinion on what is best...so most people simply do a full RGB scan,
> and convert in PS using their own mix.
> 
> Austin


I don't doubt you,  but can you cite some sources for this statement?


Andy

> > Keith,
> >
> > If it merely used the green channel, it would be losing information.
> > Typically, scanners that scan B&W in RGB, of which is
> %99.999999 of them,
> > they scan in RGB and use some precanned "mix".  This mix is
> based on someone
> > else's opinion on what is best...so most people simply do a
> full RGB scan,
> > and convert in PS using their own mix.
> >
> > Austin
>
>
> I don't doubt you,  but can you cite some sources for this statement?
>
>
> Andy

Hi Andy,

The RGB film scanners I've designed worked that way (in fact, the mix was
controllable by the scanner driver, not just canned), and other people I
know who work on scanners have done the same basic thing.

You can verify this your self on your own scanner, simply by scanning in RGB
and then again in B&W and comparing the grayscale histogram to the green
histogram (or any other color(s) histogram for that matter).

BTW, the way I describe is the way the PhotoShop "convert to grayscale"
works, it has a canned mix, that is published BTW, but I don't remember the
mix off the top of my head...

Austin