STEREO PROCESSING 31 Ibe made after the dry slide is examined in the viewer, but YOII
can learn, by looking through the slide at the yellow-green safe-
light to judge very closely.
Because the transparency will reproduce many times the tonal
range of the paper print, the negative should be made for trans-
parency printing. You will find no negative which works at its
best in both media. The negative for the transparency will be
more vigorous than usual and will, in fact, be fully as vigorous
as the hardest negative considered suitable for planar projection
printing under modern methods; harder in fact than most ama-
teurs ever use.
Projection.-Projection printing has already been mentioned.
If the image is enlarged two diameters, the viewer should have
lenses whose focal length is twice that of the camera lenses. This
is the only significant factor in projection printing. Extreme care
must be used, because the slighest softness of focus becomes visi-
ble in the stereoscope.
Toning.-Perhaps no division of amateur photography lays such
stress upon toning as does the older stereo field.
Among the old guard a stereogram simply isn’t ready for view-
ing until it has been gold toned. Again no one seems to know
why. The technique apparently was born at the period when a
commercial photographer couldn’t sell a print unless it was
“sepia.” For some reason the richness of black did not appeal.
Planar photography recovered from the fad, but it remained a
stereo requirement. It is true that occasionally a gold toned print
is really beautiful, usually it is a ghastly “half-baked” brown, not
greatly different from the usual “sepia” tone.
If you grow to the point where you wish to make use of gold
toning, you can purchase the necessary materials ready mixed at
any photographic store. Just follow directions. It is a tricky process
but eventually you can master it. I do not suggest you take the
time to make up your own solutions.
The transparency makers also lay stress upon toning, but with
better reason. The transparency does have an extended tone range,
and often it is visually harsh when the gradation is good. The
toner most favored is even more temperamental than gold toning,
but yields a beautiful blue-gray range of tones which is the most
realistic monochrome for outdoor scenes I have ever seen. This is
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