102 THREE-DIMENSIONAL PHOTOGRAPHYeach slide. To make the collection readily accessible, this number
should be placed upon the edge of the slide so that it may be read
without removing the slide from the drawer.
The glass (or plastic) slide may have a small number, written
upon paper and sealed over the edge by a strip of transparent,
cellophane tape.
It is easy to work out a complete indexing system for rigid card-
board mounts. These mounts are stacked so that each slide over-
hangs the one below it by ‘/8 inch as shown in Fig. 6-5 (1). In
this position a color stripe is painted over the whole pile of ten in
one straight line as shown (B). When the pile is straightened up
as in (2) of the same figure, the colored portions assume a stag-
gered sequence. If any slide is removed its position is easily ascer-
tained by the break in the regular sequence. This provides the
basic group indexing for ten slides.
The second ten (1 1 to 20) are indexed by painting the stripe
at D of Fig. 6-5 (1). This will place the staggered indicia at the
right of center.
The actual numbers are color coded in spectral sequence, i.e.,
1-20 =violet; 2 1-40 =blue; 4 1-60 = green; 61-80 = orange; 8 1-100 =
red. This provides for a sequence of numbers up to 100.
For multiples of 100 the center stripe (C) is color-coded.
1 - 1 oo = plain 50 1-600 = yellow
10 1-200 = gray 60 1-700 = orange
201-300 =violet 701-800=scarlet
30 1-400 = blue 80 1-900 = brown
40 1-500 = green go 1- iooo = black
For the second thousand a second stripe is added to (C) so there
are TWO narrow stripes down the center. The marking is car-
ried on to any desired extent.
Classification is also desirable, and for this purpose the ends
(A) and (B) are color-coded according to any color code you may
wish to use. For example you might have for (A) the following:
violet =scenic yellow =water
blue =flashlight orange =action
green =figure red =animal
For (B) you will have a code for each of the “A” classes. For
example under Green A (figure) you might have: