Re: exposure calculation with paper negatives

i've found that the exposure times for ilford rc and fiber papers are
quite different. a time derived from rc paper is not likely to translate
to fiber... i use both the rc pearl and the matte fiber quite a bit for
different things. the rc pearl seems to "blow out" faster in the
highlights, while matte fiber is thicker paper, and harder to work with
when printing (it curls). the paper i most like for pinhole negatives is
kodak polymax single weight semi-matte fiber... a mouthful... the best
gauge really is just to do it several times until you get a feel for a
new camera.
/aaron

> ------------------------------
>
> Date: Tue, 16 Mar 2004 23:34:03 -0600
> From: "Tom Miller" <tomwmiller@comcast.net>
> Subject: RE: [pinhole-discussion] exposure calculation with paper
> negatives
>
> Hi Earl,
>
> Recently I've been working a lot with Ilford MG IV Fiber Matte paper.
I
> did
> a series of tests and determined that, for a 7 inch (178 mm) focal
length
> camera with a .4 mm aperture, the proper exposure in full sun is 70
> seconds.
> You're using a slightly longer focal length, but also a slighly larger
> aperture, so I'd guess that your exposure should also be about 70
> seconds in
> bright sun. This is assuming that the emulsion on pearl and matte
> surface
> papers are similar (and this is a BIG assumption). You might try the
> 70-second BDE rule-of-thumb and see if it helps.
>
> I also read Chuck Flagg's response that he has his students do
in-camera
> test strips. This is an excellent idea and might be something to try,
> too.
> I've found that papers vary widely in sensitivity to light: in one
camera
> that I use a lot, Kodak P-Max Art RC has an exposure of 8 seconds in
> bright
> sun, whereas Cachet RC warm-tone matte needs 45 seconds (about 2 1/2
more
> stops).
>
> Hope this helps.
>
> Tom
>
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Received on Wed Mar 17 12:49:06 2004