The DARKROOM COOKBOOK, Third Edition

150 THE DARKROOM COOKBOOK
PRINTING
Printing-out papers are printed using a wooden contact-printing frame with a hinged back or
between a piece of glass and a fl at plywood board of the same size as the glass. If the paper is
not thoroughly dry, it can cause stains on the negative. If you’re concerned about damage to
your negative or are using an historic negative, place a thin piece of clear acetate, available at
art stores, between it and the paper.
When exposed to the light source (sunlamp or sunlight), the paper will darken quickly at
fi rst and then slow down. When using a contact-printing frame, you can check the progress
of the print by taking the printing frame away from the primary light source in a darkened
room and unhinging the long side of the back. Peel back the edge of the print to inspect the
progress. Be careful not to fog the paper by exposure to bright light or to move the registration.
The highlights should be darker than the tone desired in the fi nal print, and the shadows
may even have a metallic sheen called bronzing. With practice, you’ll learn to judge when the
print has reached the proper density.
Contrast Control
Four techniques can be used to control the contrast of the print.
1. Printing can be done slowly in the shade on a sunny day or by artifi cial light.
2. A piece of tracing paper can be placed on top of the glass to slow down the printing in the
shade or under artifi cial light.
3. The sensitized paper can be fumed with ammonia.
4. Potassium dichromate can be added to the salting solution.
Chemical Control of Contrast
Fuming the paper with ammonia changes the pH of the silver halide to an alkaline state. This
technique was used in the nineteenth century with all printing-out papers. Buy a large plastic
storage box and line the bottom with cotton wool. Drizzle three ounces of household ammonia
evenly over the cotton and close the lid. Do not breathe the fumes when opening the lid.
To fume, tape the paper sensitive side down to the underside of the lid by four corners and
replace the lid. Fume for about 1 to 3 minutes. Remove the paper and allow it to out-gas for
about 2 minutes before placing in the printing frame. Fuming is very effective. The paper will
print much faster and will have more contrast.
Controlling Contrast by Light
Further control can be gained through the choice of light source. The slower the printing, the
higher the contrast. The higher the amount of ultraviolet (UV) light, the lower the contrast.
Sunlamps and direct sunlight both contain relatively high amounts of UV and give the lowest
contrast. However, by placing one or more sheets of tracing paper or a sheet of frosted glass