Digital BW, The Print

I've been looking at some of the various ways of producing black and white from colour and 
wondered if there were any ways to get better results if, for some reason, you had to start 
with JPEG colour originals (8 bit RGB).

It seems that if you are using Photoshop to do the conversion to black and white, then you 
get a better result by turning the 8 bit image to 16 bit first. I did some checks and have a 
page with example 8 and 16 bit B/W conversions which shows that there is indeed a 
difference that might just show up in your results if you want the best quality. Effectively, 8 
bit RGB can give you up to 10 bit greyscale depending on how you do the conversion
http://www.northlight-images.co.uk/article_pages/16_bit_black_and_white.html

If anyone on the list has more detailed knowledge of Photoshop's internal maths, I'd like 
to know if I'm on the right track with this one? :-)

I suspect that the differences might not be too obvious unless you were applying several 
quite hefty adjustments, which I'm more likely to be doing when working on B/W -- although 
I'd not usually be working from a JPEG in the first place...

Keith Cooper

Hello Keith,

>I've been looking at some of the various ways of producing black 
>and white from colour and wondered if there were any ways to get 
>better results if, for some reason, you had to start with JPEG 
>colour originals (8 bit RGB).
> 
>It seems that if you are using Photoshop to do the conversion to 
>black and white, then you get a better result by turning the 8 bit 
>image to 16 bit first. 

I have tried this with my pocket digicam images and it does seem to
help some to lessen badly combed histograms.  It isn't the same as a
true 16 bit image, but every little bit helps so it's standard
procedure for me now.

Regards,
Clayton


Info on black and white digital printing at    
http://www.cjcom.net/digiprnarts.htm