Digital BW, The Print

Seems like people are looking for magic where there isn't any.  You 
get an RGB image (ie. an NxMx3 matrix) and you need to covert it to a 
grayscale image (ie. and NxM matrix).  The only way to do that is to 
combine the RGB channels into a single grayscale value somehow.  This 
is what the channel mixer does, just simpley sums scaled values from 
each channel.  If you convert to HSB or LAB color space you don't do 
anything but transform you data into a new coordinate frame before 
essentially channel mixing... you don't gain anything in the 
transformation because you essentially haven't done anything... and 
there isn't any magic.  You can do more fancy math during your mixing 
to directly control contrast etc. or you can do it later using curves 
etc., but if done correctly it shouldn't matter how you do it (ok, 
that is theoretically true... in PS, 8-bit data rounding errors 
occur, but you shouldn't be pushing your images that far anyway).

If you like the sliders of one tool over the other, no reason that 
you shouldn't use it, but you aren't going to get better results 
using one method over another (unless of course you don't understand 
what you are doing).

Mark

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, Keith Cooper 
<yahoogroups@n...> wrote:
> Hi
> 
> I've got a web page at <http://northlight-
images.co.uk/bwfromcol.html> that
> compares different methods of conversion and has some examples from 
Imaging
> Factory.
> 
> If anyone has any PhotoShop methods that are not included, please 
let me
> know and I'll add them to the page...
> 
> 
> bye for now   
> 
> Keith Cooper
> 
> Northlight Images
> http://northlight-images.co.uk
> Photography - Digital Imaging - Apple Mac Consultancy
> 
> Tel +44 (0)116 291 9092 Mobile +44 (0)780 162 9397