[pure-silver] Re: Kodak Gray Negative Contact Screen
- From: Jean-David Beyer <jeandavid8@xxxxxxxxxxx>
- To: pure-silver@xxxxxxxxxxxxx
- Date: Thu, 23 Feb 2012 18:18:56 -0500
Bogdan Karasek wrote:
> Hello,
>
> I was just cruising the darkroom section on ebay and came across this
> " Kodak Gray Negative Contact Screen" (#160722629230). I did a
> Google search and basically I was informed that it is used for making
> "contact prints" which is what I assumed. But what exactly does it
> do? nothing. Talk of lines per inch but that doesn't tell me
> anything.
>
> Can anybody here give an explanation as to why one would want to use
> such a beast? It does serve a purpose....
>
I happen to detest contact screens, but that is because I prefer sealed
glass crossline screens for half-tone work. They are much more practical
and give better results iff you understand how they really work and take
the trouble to learn to use them.
But if you cannot be bothered, a contact screen is OK for quick work
where quality is not too important.
In the simple case, you can photograph a continuous tone subject and
make a negative image that is strictly black or strictly clear, but
divided up into a lot of little dots whose diameter (if the dots are
round) is proportional to the density that would have been produced
without the screen. The reason the image is black or white is that litho
film is used.
In the past I have posted pretty well how a glass sealed screen works,
so you will have to look it up. It is described in a few books, but most
of the books have it wrong. As far as I know, the only book that has it
right is "The Autobiography of an Amateur Inventor" by Frederick E.
Ives. But that was privately printed and difficult to find.
--
.~. Jean-David Beyer Registered Linux User 85642.
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