Re: Newton Rings

Greg Schmitz (gws1@columbia.edu)
Wed, 21 Jun 1995 22:46:09 -0400 (EDT)

Somewhere I have an article on Newton's rings, but can't seem to put my
hands on it at this moment (so much for my filing system Judy) so the
following will have to suffice for now. BTW my experience has been that
humidity is a big factor as is the surface of the base and sometimes the
emulsion sides of the film. The base side is almost always a problem and
the emulsion side of some films in some developers can also be a problem;
some film/developer combinations produce a very "shiny" emulsion side.

The following is from Adams, A. THE PRINT. The Ansel
Adams Photography Series; book 3, 1983, pg. 24:

Another annoying problem that may occur with a glass negative carrier
is the appearance of Newton's rings when the film is pressed against
the glass.... They are caused by the interference effect of light
reflecting within the extremely small space between the glass and the
negative base. This does not occur between glass and the emulsion
side of the negative [I disagree see my note above, sometimes the
emulsion/glass interface will result in rings -gws]. Changing the
pressure between glass and film may eliminate them, since with totally
uniform contact between negative and glass, no rings occur. Newton's
rings are aggravated by high humidity, and thus slightly heating the
glass may help. I have found that the "anti-Newton-ring" glasses may
give a slight textural effect that is disturbing [ditto -gws].

--greg schmitz

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