PHOTO STAMP PRINTER (Sep, 1949)
PHOTO STAMP PRINTER
By Kenneth Murray
PRINTING up to 100 stamp-size photographs on a single sheet of 8×10 in. paper is easy with the MI Printer. After processing, each sheet can be gummed on the back, and cut so that individual stamps are available for attaching to personal stationery, books and other possessions.
Printing can be done from any negative; the mask opening is 7/8 x 7/8 in. This leaves a narrow white border on each stamp. Without changing the guides, you can substitute a mask with an opening twice as large and print 50 exposures on each sheet.
The MI Printer is a complete unit and the exposure is made automatically each time the platen presses the photo paper into contact with the negative.
The device consists of a top piece fitted with paper guides; two wooden supporting rails; an illumination compartment, and a hinged platen which operates a contact switch each time full pressure is applied.
A 19-1/2 x l7-in. piece of 3/8 -in. plywood or 1/4-in. black Tempered Masonite is required for the top. Round off one edge as indicated in the drawings, then cut a 1-7/8-in. square hole in the center for the printing aperture with a jig saw. A small keyhole saw can also be used. Rabbet the edge of the opening so that it will accept a square of glass for a flush fit. A suitable piece of glass is that sold for mounting 35mm. frames for projection in a 2×2-in. projector.
The supporting side rails and illumination enclosure are positioned and glued to the underside of the top. One end of the enclosure remains open so that the flash of fight from it can be seen and length of exposure accurately calculated. It may be covered with red Cellophane if desired, although in practice this was not found necessary.
The illumination and switch arrangement can be seen in the photo. A small white-frosted 7-1/2-watt lamp in an ordinary porcelain receptacle is used. The socket is wired in series with an ordinary doorbell push button. As the lamp draws very little current, this type of switch was found to be entirely satisfactory, although it definitely should not be used for other applications where a heavy current is required.
A hole is drilled immediately above the push button for a wooden dowel. The dowel, serves as a push rod when it is depressed by the lowering of the platen. The working end of the latter is cushioned with a square of sponge rubber cut from a kitchen sponge.
It will be necessary to sand one end of the dowel push rod down gradually until it actuates the switch only when pressure is placed on the forward end of the platen. This is required because the printing paper must be pressed firmly against the negative before each exposure is made.
Strips of thin fiber or red cardboard can be used to guide the printing paper into 100 or less different positions. They are cemented directly to the top. If you use rubber cement, the strips can be removed for adjustment or replacement without leaving a mark. Cut the strips and space them as indicated in the diagram. The printing paper is started at the lower right corner and moved to the left, with one exposure each time it is shifted into position against the edges of succeeding guides. At the extreme left position it is raised one frame and exposures continue while the paper is shifted to the right.
Cut the masks from thin black paper, or use special Kodak masking sheets. Average negatives printed on contact paper will require about two seconds exposure. A little practice will make it easy to keep the exposures uniform.