Photopolymer plate phenomena

An interesting occurrence the other day. . . We were marking up some paper for cutting down with pencil notations (true cuts, gripper edge, etc.) and when we went to print prep we started with the top sheet cuts (with the markings) and noticed the pencil marks transferred to the photopolymer plate. When we applied a light, somewhat transparent ink, the pencil marks printed! and again, and again. Seems like there is some potential there for interesting work on solids.

Something else from a long while back. . . Fine garden soil placed on top of a photopolymer plate before exposure makes the best cloud patterns imaginable. Don't use the vacuum and turn those fans off as you don't want that particulate matter getting into the machine. This might only work on steel-backed plates, since they don't flex.

Carbon dioxide bath for photopolymer plates

When the photopolymer plate process first emerged in the early 1960s, a standard industry practice was to revitalize used plates with a carbon dioxide bath. This was also used to condition raw photopolymer plates prior to exposure. This practice was discarded when plates were more and more considered disposable items.

However, this practice does revitalize photopolymer plates to some extent, and has been proven to relax some curled plates.

Previously procesed photopolymer plates degrade in the presence of ozone, UV light, moisture variance. Antiozonants and carbon dioxide act as preventatives.

A carbon dioxide bath is easily constructed. Any kind of small cabinet can be used as long as you can insert a wire shelf and a plastic container into it. The plates are placed on the shelf above the container and dry ice is put into the container. Let this sit until the dry ice has evaporated.

Deckle edge finder

Mini LED Runners Hat Light

Printers may sometimes need to preserve the deckles on handmade or mouldmade paper but this can be problematic in registration. A not uncommon practice is to file away the deckle where the paper fits into the guides. This leaves a barely discernible registration edge that is even less so when the paper is dampened. This can be accomplished in a number of ways but to find the edge where the leakage (the deckle) begins and where the true edge of the paper thickness ends is quite difficult.

I was watching a student working on some deckle edged paper the other day and noticed he was using a small light and marking the paper with a pencil before making his cuts. When I inquired he showed me his device, a runner's mini LED (straight line) hat light clip on. He placed the paper with the deckle just beyond the edge of the table and ran the light along beneath the paper. The edging was perfectly revealed!

European composing sticks

Sliders [composing sticks]
Shown are two composing sticks, one English (top), one German (a Bacher). These are extremely precise in regard to their parallel measure. As they use a sliding action they are best adjusted to the desired measure with a composing rule or a piece of furniture (preferably plastic Resalite or aluminum) rather than wood.

Photopolymer Plate Pickup


A pad knife (aka tablet knife) is a very convenient tool for lifting steel-backed plates on magnetic flatbases. The blade is short enough for convenient manipulation and wide enough to prevent the plate from bending; and its front rounded edge keeps it from scratching or cutting the surface of the base.

I also use this handy tool to remove washed out plates from the platen of the photopolymer platemaking machine.

These are commonly used to separate padding and are available from various distributors of printing and binding supplies.

Press operator side paper guides



These are available from Bar-Plate.

Press points

Press Points

Steel press points are often used on cylinder presses such as a Vandercook to prevent slurring of the type at the bottom of the sheet. They are less than type high thus do not print. They are locked in the lower part of the form outside of the printing area. These catch the sheet as it flips away from the cylinder and prevent it from dragging across the type.

Side guide

os-side-guide-with lip
Old style Vandercook 219 brass side guide. Here it is shown mounted on a SP-15. Note flared lip (doesn't abrade the paper sheet). I prefer this to the new style Vandercook guides. Reminds me of an old steam locomotive (when I was a kid, we had railroad tracks at the back end of our property, and these guys would fly by once or twice a day, really cool).

Registration Tool (plate shifter)

bookbinder's pallet

A bookbinder's brass pallet can be used for nudging steel-backed photopolymer plates into position. This works especially well on a Bunting Cerface Magnetic Flat Base. It will not scratch the surface nor be drawn down by the base magnetism.

Drawdown Third Hand

Tympan drawdown third hand

When adjusting the cylinder packing a lowly rubber door stop can be used to prevent the tympan draw sheet from drooping down onto the inked form and/or to prevent breaking friction fingers.