Re: umm (ortho-litho development)

Hi:

Depends on what you want to do. One of the standard kodak ortho
developers in called fineline - mixed as two stock solutions which are
combined prior to development. This gives a high contrast negative

The developer should give some info on effective film speeds, depends on
the light source.

One can also use diltuted dektol to make a less high contrast negative.
These end up looking like very contrasty negs with a little continuos tone
in some regions of the negative - (this depends upon exposure).

One can even get a continyuous tone negative from orhto film if processed
with something like Soemarko's LC-1.

The processing is the same as standard film except for the developer.
Some orhto film get tiny dots - usually called pinholes if an acid stop
bath is used. I've always used water as a stop for orhto film.

For taking in camera ortho shots for a high contrast negative the exposure
determines what falls into the black and what falls into the white. There
is a threshold, figuring our where that is, is a trick.

Many people make high contrast copy negs by contacting printing
continuous tone negs onto orhto film (making a positive) and contacting
this again to make a negative.

Can also use an orhto mask from a contact copy and sandwich the neg and
orhto copy offset

Can also "posterize" an image by making successive exposures with diferent
thresholds and use these to print each theshold image in a different
color. Would have to use a printing process that allowed succesive prints
of different colors on the same paper. - a print making or maybe
gum-bichromate.

See if you can find the book "High Contrast" by J. Seeley

Gord

On Wed, 20 Feb 2002, R Duarte wrote:

> ummm, sorry.. i also wanted to ask if anyone has sort of a summary of
> developing techniques for that ortho-litho stuff (eg which chemicals in
> which dilutions). i wish there was an easier way to search the archives.
> :-/
>
> thanks again,
> rob
>
>
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---------------------------------------------------------
Gordon J. Holtslander Dept. of Biology
holtsg@duke.usask.ca 112 Science Place
http://duke.usask.ca/~holtsg University of Saskatchewan
Tel (306) 966-4433 Saskatoon, Saskatchewan
Fax (306) 966-4461 Canada S7N 5E2
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Received on Wed Feb 20 23:44:43 2002