Last weekend I taught my first Photo-Plate Litho at Leicester Print Workshop. It went really well – there were 7 students on the course, (one of which has already joined up as a member to come and do more!), and all had brought a great selection of images with them to work With. Some had brought digital images such as photographs and scanned drawings, printed as a positive onto acetate. Others brought hand-drawn images to work with, made by drawing onto transparent drafting film with materials such as pencil, graphite and crayon, and guache and acrylic paint for wash-effects. Very fine detail in both drawn and digital images can be picked up in this process.
The positive transparency is taped to the photo-plate, which comes pre-coated with a light-sensitive emulsion. The plate is then exposed to UV light. The light is blocked by the opaque image areas, and passes through the transparent non-image areas. When the plate is then developed, the non-images areas wash away to leave bare metal underneath, and the image areas – where the light was blocked – stay on the plate. This creates the image on the plate.
Gum Arabic is then applied to the plate to help establish a chemical difference between the image and non-image areas. The plate is then printed by first washing off the gum, then keeping the plate damp while rolling on lithographic ink. The plate can be printed on either a litho press or an etching press. Damp paper is usually used to ensure as much detail as possible is picked up.
Plates can be printed in black and white or in colour, and some of the students from my course went on to do another day the next day with LPW lithography technician and artist Serena Smith, where they made more plates and experimented with printing a number of plates in register to produce multi-plate prints.
I’m really looking forward to teaching the Photo-Plate Litho course at West Yorkshire Print Workshop on 19th October.
Here are a few photos from the weekend…