Board_Advisors_etc 3..5

A third limitation is that photographers making
contact prints cannot easily crop the image
because the entire negative is pressed onto the
unprocessed photographic paper. It is possible to
construct some sort of mask to block out areas of
the image deemed unnecessary to the final print,
but it is much more difficult to crop with contact
printing than it is with regular projected/enlarged
negative printing.

Contact Printing and Alternative Processes

Contact-printing techniques are used in some alter-
native-processing photographic techniques, such as
gum bichromate printing. In gum bichromate
printing, a sheet of otherwise non-photographic
paper (or other surface, such as cloth) is coated
with a photo-sensitive emulsion of gum arabic
and ammonium or potassium bichromate and
then exposed to the sun (or other source of white
light). Since no type of projector is used, gum
bichromate prints are made as contact prints with
negatives the same size as the desired final prints.
If one does not have access to a large-format
camera, but would still like to use large negatives
for contact printing (especially for use in alterna-
tive processes like gum bichromate printing), a
small- or medium-format negative can be enlarged
onto sheet film (such as Ortho or Kodalith films),
which is them processed in regular (though often
much more-diluted) paper developer and chemis-
try. After processing, the film’s emulsion is, like

regular black and white negatives, black and clear.

Rather than the unexposed areas remaining white,

as they do on black and white photographic paper,

the unexposed areas on Ortho film rinse to clear in

the developer. Since the first-generation Ortho film

print is usually a positive print (since it is achieved

by enlarging a negative), a photographer who is

interested in ultimately having a positive end-pro-

duct contact print will first need to make a contact

print with Ortho-on-Ortho to achieve a large-size

negative. This large sheet film, which can be gotten

fairly reasonably-priced in sizes up to 20^00 
 2400 ,is

an affordable halfway-point for photographers

interested in working with contact prints with

film negatives, but who do not have access to a

large-format camera.

A photographer can use contact-printing tech-

niques to make prints from things other than ne-

gatives or photographic positives; he can, for

instance, contact-print anything that is fairly trans-

lucent, such as other papers or vellums. Opaque

black (or other dark-colored) ink on those surfaces

will appear white on the contact print.

JennyAllredRedmann

Seealso:Burning-In; Darkroom; Dodging; Manip-

ulation; Safelight

Further Reading

International Center of Photography Encyclopedia of Photo-

graphy. New York: Crown Publishers, Inc., 1984.

CONTRAST

If it were not for contrast, our visual world would
be blank. It is the difference between the color and
shade of two things that allows us to separate one
from the other. One can regard this as positive
versus negative space, changes in tone, or extent
of color separation, and the appearance of simple
texture. In photography this works out to offer
three opportunities to address contrast. The first

is that of subject brightness and the degree of

change of this brightness across the area being

photographed. The second opportunity comes

with the negative. Negative contrast can be con-

trolled by changes in exposure and development as

well as other more specialized techniques like

masking, chemical reducing, or chemical intensifi-

cation. Print contrast and the techniques of print-

CONTACT PRINTING