Photopolymer Film

The photopolymer film, a product of the electronics industry, offers several possibilities to transfer paintings, drawings, photocopies and computer printouts to the plate. It is a photosensitive film which is laminated onto the plate. The stencils (which have to be drawn or printed on transparent paper) are transferred to the plate by UV-light-exposure. The exposed plate is developed in a mild soda solution.

There are two possibilities:

Photopolymer film non-etched

Here the stencil is exposed to the film with the help of an aquatint screen. The stencil in this case is transferred including the grey tones. The impression of this technique reproduces the characteristic features of the used materials very closely ( chalk, pencil, gouache, etc). The developed plate can be worked on further by hand with the etching needle or similar tools. In this case, only the exposed film is printed, not the plate itself. The film can be removed after printing and the plate can be reused.

Photopolymer film etched

Here the stencil is transferred to the plate for being etched later. After the exposure, the film is developed, enabling the plate to be etched where opaque portions of the stencil cover the film, thus preventing the film from hardening under the UV light. Where the transparent parts of the stencil let the light shine onto the film, the film is hardened and later will protect these parts from the etch. The advantage of this technique in comparison with the non-etched type is that after etching the plate can be worked on with other intaglio techniques. Here it is also possible to transfer and etch grey tones.

Exposure unit

An exposure unit can easily be built. It should be a cabinet which can be closed with a light-proof door or curtain. Upon that the UV-light-source has to be installed in a way that allows the light to just go down into the vacuum frame, not directly into the user's eyes. The vacuum frame is located inside the cabinet itself.
A vacuum frame is a frame that contains a rubber blanket covered by a glass plate. Via a small hole in the blanket and leading through a tube, the air between the blanket and the glass plate can be sucked out by a vacuum cleaner or air pump, creating a vacuum.

For a perfect exposure there must not be any space between the stencil and the plate. The plate and the stencil are laid on the blanket and covered with the glass plate, creating a vacuum. While the plate and the stencil are in close contact from the vacuum, the plate is exposed to the UV light from above.
Stencils have to be on transparent paper. Photocopies can be made transparent by rubbing the paper with oil. This has to be controlled against a light source and later be dried in the drying cabinet, though not every kind of photocopying paper is suitable for that.

The photopolymer film (which comes in rolls) has to be laminated to the plate.

The soft, sensitive film is sandwiched between two layers of protective plastic. Cut a piece that is a bit bigger than the plate. To remove the soft inner matte foil easily you should first cut a corner with a knife. The soft foil can now be torn off. The film is now laid down on the bed of the press with the open side up. It is important that the bed is covered by a perfectly even surface (such as a piece of Plexiglas); otherwise bubbles will emerge on the film after lamination. Before running the plate through the press the plate should be covered with plastic to avoid the edges of the film sticking to the blankets. After lamination the excess film should be removed by using a sharp hobby knife.
Laminated plates should be stored in lightproof wrapping.
It is recommended to wear gloves while handling the film. The liquid or dry remains of the photopolymer film should be collected and be given away to the right authorities.

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Copyright 2006 Eva Pietzcker and Miriam Zegrer