A glass slide consists of two pieces of glass: one pane
containing a hand-painted image and the second pane placed over the image
for protection. These were used in a projector called a Magic
In the early 1900's, the beginning films
were only one or two reels. Each time a film ended, the show would stop
while the projectionist changed reels. Some theatres would provide sing-a-longs
between reels, accompanied by illustrated song slides flashed on the screen
by the Magic Lantern. Usually the son or daughter of the theater owner would
lead the singing. Jack Warner, later the head of Warner Brothers, led the
singing in his familys Nickelodeon in Pittsburg.
By the 1910s, some theaters used the Magic
Lantern to show a slide of a coming attraction, show times or local
There were primarily 2 different sizes of
1. The first and most common size was approximately
3 1/4" x 4" and was divided into 2 primarily different types (apparently
made by two competing companies).
Both types consist of two panes of glass
held closely together, and the inside surface of the glass has been imprinted
with a positive (not a negative) image of the coming attraction ad, almost
always in full color. There is almost always a solid black border on both
panes on the outside of the image.
the first type of slide, the two panes measure exactly 3 1/4” by 4”,
and they are held together with pieces of black tape (like duct tape) on
the edges of the two panes, overlapping the front and back edges by an eighth
of an inch or so. These often have a white circle in the corner of the slide
(between the panes). Probably this was so that one could tell the bottom
of the slide without holding it to the light. Notice the blank border across
the bottom. This is left for listing local show days if the local theatre
wanted to , similar to window cards.
second type of slide consists of two panes somewhat smaller than 3 1/4”
by 4”, which were held together by two pieces of light brown cardboard,
usually with 8 staples holding the cardboard together. Almost always, the
cardboard would have the name of the film stamped on it, and have the manufacturer’s
name imprinted on it. Quite often additional printing were on these. NOTICE:
there's also the blank across the bottom for local dating. The main difference
between is the way they're held together.
It seems the “black tape” type was mostly made
from the earliest silents through the mid-1930s and that the “cardboard”
type was made from the early 1930s through the early 1950s. It does not
seem that one type is superior to the other, although it does seem that
the cardboard slightly helps to shield the glass from aging, as those are
often found in better condition. This was probably the forerunner to the
film slide which is done the same way.
2. The second size was used a little later
for "fancier" theaters. The Brenograph projection systems were
technically similar to Lantern format, but in a much larger 4" x 5"
- 102 mm x 127 mm size glass slide. The larger format and more powerful
throws were intended to provide a luminous ambiance to larger theatre environments,
especially those of the Movie Palaces. Special designs were produced for
curtain arrangements, proscenium features, and ceilings, including "scudding
clouds" facilitated by the standard double throw which allowed inventive
dissolves and fades by a talented projectionist. Modernized versions of
the Brenograph are still in use today, but the wonderful glass slides are
a thing of the past.