Re: Pin holes in my litho
j.r.anderson ()
Wed, 22 January 1997 11:24 PM
>
>Some of my students get specks on lith film, others don't. All are using
>the same film (freestyle lith) developer (Dektol) & stop bath (acetic
>acid). The specks are clearly dust & when they REALLY swab down the
>staging area, generally disappear, except of one case last fall when no
>amount of wash and wipe was a cure, but she said her darkroom mate was an
>incorrigible slob so we blamed that. I've not seen "pinholes" that I
>recognized as such at all, tho I've read about them.... Is it possible
>that the reason the pre-baths help is by washing the dust off before
>development? (That wouldn't affect the blobs made by dust sitting on the
>film during exposure, of course.)
>
>My impression, however, is that the phenomeon is independent of whether
>the lith is developed as high contrast or con tone...
>
>Judy
The only problem with the dust theory is that an analagous problem sanking@hubcap.clemson.edu (BLACK
dots + white dots) can often appear on lith PAPER as well - this is said by
some to be cured by adding some sodium sulphite to the dev... something to
do with restraining the process without deactivating the dev.... but I find
it a very erratic and difficult problem to predict. Sometimes it's there,
sometimes it isn't. I wonder what theory people have for the black dot
problem?
By the way, I have found that different paper types are much more or less
prone to these problems...
Jonathan Anderson
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