From: C Downs (fardog@mindspring.com)
Date: 09/25/01-11:45:50 AM Z
-----Original Message-----
From: Sandy King <sanking@CLEMSON.EDU>
To: alt-photo-process-l@sask.usask.ca <alt-photo-process-l@sask.usask.ca>
Date: Tuesday, September 25, 2001 11:21 AM
Subject: Re: Un Sharp mask . no diffuser necessary
As I understand your explanation of the technique, you are making the
unsharp mask with items arranged in this order.
1. Exposing light
2. Sheet of white acrylic
3. Original negative or transparency with the emulsion side in
contact with the white acrylic.
4. Film being exposed, emulsion side up.
Many texts on making unsharp masks suggest placing a thin sheet of
glass or sheet of clear mylar between the original
negative/transparency and the film being exposed. You do not do this?
When using the unsharp mask in making exposures what is the
orientation of the negative and mask?
Sandy King
The way you have it will work great and in some films you can place the
emulsion of the mask downward if the type of film backing allows - so that
you expose through both pieces of film with the emulsions as far apart as
possible.
For many years I used different types of intermediate diffusion sheets
but have found them unnecessary at best. A pain at worst. Many of the folks
now writing about unsharp masking are switching to the no diffuser method.
The white plastic layer seems to give quite good diffusion if used in
contact with the neg.
When printing I place the original neg emulsion side down in the
enlarger {as normal} or toward the paper in contact printing with the mask
on
top in registration. The orientation of the mask emulsion will vary with
film type due to the way you make the mask { emulsion up or down depending
on the type of film backing..if I can print through the backing ...I do...
to get the extra distance and slight diffusion and also with some films it
slows down the exposure time enough to even burn and dodge your mask - the
slower exposures are also easier to time correctly and even the slowest
masking film is very fast if not TOO fast for easy working with. }
Working this way you can pre-punch or "strip in" and punch your original
neg in total light so that you can see it and make no mistakes.
My method of making the mask:
To _Start_ with the _Bottom_ of the layers is the White Acrylic sheet,
with taped on registration pins facing up, followed by the original neg,
then the masking sheet of film and finally a black layer { I use Black
Flocked Material from Edmund Scientific - cheap and soft on the film - with
a thin sheet of glass, plywood, or plastic sheeting as the substrate that
the black flocked material is fastened to - BTW the Black flocked material
comes in "peel and stick" sheets }
The whole sandwich is then fastened together with clips and inverted so the
white sheet is on top. The exposure is then made.
I use both a "pin punch" or "pin plates" depending on size and number of
registration points I think will work best. For smaller negs I like the
Wess punch as it will put tiny holes in the actual film outside of the image
area and does not require taped on tabs or stripping in the neg { if
stripping is necessary I use old film.}.
Wess pin punches { $40-200} can be easily modified to work with all sizes.
Pin plates { found at drafting supply stores along with the cheap hand
punches} can be used instead of punching the original film. They can be
taped to the white sheet if you leave enough room at the edges and the black
cover sheet can be left just short of the pins or drilled to fit over the
pins. For large negs I like a non-drilled method with small pieces of pre
punched film taped to the original neg.{ these "tabs" can be very small if
necessary for your setup.} Three work well up to 40 x108 inches which is
about as large of neg as I have worked with { we often did contact printing
with a blow- back or enlarged negative system } The pin plates are taped
down first then the original neg is put into place. Tabs of old film are
then pre punched and placed over the pin plates and taped to the original
neg. I use two on the long dimesion and one at a rt angle on the shorter
dimension. I then pre-punch small tabs made of old film for the masking
film layer and place them over the pin plates with the edges pre-taped and
the "stick-em" side of the tape upward. This allows me to just place the
masking film over the sticky tape and press down since this has to be done
in the dark. Keeps everything simple. The black backing is then placed over
the "sandwich" , the whole "sandwich"clipped together and turned over to
make the exposure. Notebook clips work for smaller sizes.
This same setup can be used to make contact prints - if reversed in its
order of layers with the printing paper next to the blackflocked material
then the original neg and finally the masking neg with the white sheet on
top. This is of course done in reverse order with the white sheet on the
bottom until it is turned over to make the exposure. This always allows you
to work with the original neg with the lights on to prevent any scratches
from mis-handling in the dark. I _DO NOT_ like to handle any original in
the dark and try to put it over "pins"....just trouble waiting to happen in
my mind...:o)
If you use "Leader-card" tape or other types of tape that will stay on if
wet you can leave the "tabs" on the masking film layer during processing to
make alignment extremely precise as the tabs are left in place on the
original. There are also many types of diminsionally stable tape by
different manufactures that would work fine.
AIR DRY masks without heat as even the best film bases will move a small
bit with heat drying and can leave nasty lines around part of the image!!
For 4x5 or smaller negs Wess makes a punch and Beseler makes a glass
carrier with the pins already in it for enlarging.
Reg pins sure help but are not necessary if you have time and nerves to
spare! Young eyes also help along with good tape for the edges!
Chuck
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