Re: Digital negatives for gum printing

[petermarshall@cix.co.uk (Peter Marshall)]

> In my experience he is right. The first time I printed a negative in 
> half
> tone dots that someone from the list had sent me, it was a revelation: 
> You
> could almost do no wrong in exposure. If you look at Kodak's diagram of
> its halftone dot from its vaunted dedicated film (2000 something or 
> other)
> it suggests why -- the dot really is ON or OFF with straight sides. I
> think they call it a hard dot -- no need to worry about delicate
> highlights sliding off.

Yes, it makes life easy.

I've never had a great interest in gum printing, but it was the first 
alternative process I started with and I soon came to the conclusion 
from a little reading that gum should work best as a halftone process. 

So I made a halftone screen using the grain from a photographic negative 
enlarged onto some suitable film. I think I got the idea and possibly the 
instructions for this from a book by Arnold Gassan, and used a 35mm Tri-X 
neg to make a roughly A4 screen, but it is a very long time ago. The film 
grain gave a fairly random screen.

The negs made using that - as you found from the halftone neg you tested - 
made gum very simple. Exposure isn't very critical and you can even 
develop/wash the prints with a shower hose. Perfect results (at least 
technically) every time.

What I couldn't get with this method - and why I never persuaded Terry 
King who I was working with at the time that this was the way to make gums 
 - was the kind of delicate and ethereal effect that some people manage.

I'd expect to get better results from halftone output from an imagesetter 
than a laser printer, unless you are prepared to accept a pretty coarse 
screen. Laser printer dots are not too great. 

Peter Marshall
Photography Guide at About          http://photography.about.com/
email: photography.guide@about.com
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