"Jean-David Beyer" wrote in
message .. .
On 2007-10-21, Richard Knoppow
wrote:

"piterengel" wrote in message
ps.com...
Hi, becaise it no more possible to find lith film I need
to try with a
qute common film to obtain very high contrasted
pictures.
I have Efke
KB 25 and Rollei PAN 25 at home. Can anybody suggest a
developer to
have extremely contrasted subjects?
Thanks all
P.


The highest contrast is gotten using a lithographic
developer like Kodak D-85 which produces "infective"
development. However, D-85, and similar developers, use
Formaldehyde, which is nasty stuff.

I use Kodak litho film (not much) and one of their litho
developers.
It does not contain liquid formaldehyde, but
paraformaldehyte that
is a related compound. J.T.Baker have this to say about
it:

http://www.jtbaker.com/msds/englishhtml/p0154.htm

As far as I can tell, I have never had any trouble with
the mixed
working strength developer.

There are somewhat lower
contrast developers, like Kodak D-8, using Hydroxide,
which
produce very high contrast but not quite what a true
lithographic developer gives. I don't think a lith
developer
is needed unless you are doing true line work.
Lith film is still made but I don't know where to get
it
outside of the US.
For pictorial purposes a print developer like Dektol
will give you quite a bit higher contrast on film than
the
usual film developers but at the cost of being quite
grainy.
Since print developers are cheap and easy to obtain I
would
try one first to see if the contrast is high enough.




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Actually, D-85 uses paraformaldehyde, which is a
crystaline form and becomes formaldehyde in solution. It is
a two solution developer, the two parts being mixed just
before use. I don't know if there is a more environmentally
friendly substance that can be used in stead of the
paraformaldehyde. Its function in the developer is not as a
hardener but specifically to promote infectious developemt.
This causes dense areas to develop much more rapidly than
lower densities resulting in exagerated contrast. For the
most part lithographic developers were used for line work
where the negative needed to be either very high density or
clear. Lith developers are also currently used for lith
printing. This is a sort of special effect which has become
popular in the last decade or so. A Google search for lith
printing will give you lots of hits.
For just higher than normal contrast on pictorial film I
think less extreme developers will work fine. One can use
something like Kodak D-8 or D-11 but, as I mentioned before,
probably any print developer will be enough.


--
---
Richard Knoppow
Los Angeles, CA, USA