LESSON 2
b. Some mounting tissues are designed to be used at lower temperatures
than others. Either type of tissue can be used to good advantage, but the
adhesive strength of the low temperature tissue is slightly less. Curled or
heavy prints may come loose from the mount.
NOTE: Excessive heat or prolonged exposure to heat will cause the
adhesive to be absorbed by the print and mounting board.
The
adhesive must be retained at the surface of both the print and
board.
RC paper is particularly susceptible to a bubbling or
complete removal of portions of the emulsion if too much heat is
applied.
c. Prints are often mounted solely for the purpose of preserving or
strengthening them. In such cases, the prints usually do not need a border,
and weight is the principal consideration in choosing the mount. Prints are
also mounted on a special type of adhesive, photo-mounting cloth. This is
done by pressing the cloth against the wet back on the print during
ferrotyping.
The cloth backing is used on prints which must receive
considerable handling and yet must be light and flexible.
d. When dry mounting prints, the temperature of the press should be
accurately set and maintained according to the directions given with the
tissue. Do not overheat the press, let it cool prior to beginning mounting.
e. During the actual mounting process, pressure, as well as heat, is
required.
A red light flashes "on" and "off" approximately once every
second when the press is closed and provides a means for timing the process.
f. When placing the print and mount in the press, always hold the press
open by the operating handle with one hand. Slide the print and mount into
the press with the other hand.
Even at its lowest range, the operating
temperature of the press is hot enough to burn your hand seriously.
Remember, the purpose of the press is to mount prints, not fingers.
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