Photo litho
One and two colour photo litho prints produced in David Holah’s class at City Lit. The artwork was inspired by a pair of found children’s shoes on a wall in Forest Hill near to the Horniman museum. I created a montage from found photographs, mono prints taken from photographs and text which came into my head inspired by the shoes. I manipulated the images in Photoshop to create a composite. The composite was then saved as a tiff to compress the layers. The tiff was saved as a bitmap file, first as a halftone image with 30 dots per inch.
After printing this out as an acetate and exposing it on the light unit and printing a test strip, I decided that the image was looking too coarse. I then resaved the image as a halftone at 70 dpi. This worked much better and created a more refined image.
The photo litho plate was placed face down onto the acetate on the light unit. The above prints were exposed at 2H (half light), this seemed to work well. A test strip was exposed first to make sure the exposure time is correct. The plate size should be larger than the image. The plate was developed in Hunter Penrose plate developer in a dilution of 1:8 with water for approximately 5-10 seconds. The plate was wiped gently to remove any unexposed emulsion. The plate was rinsed in water and dried with a hair dryer. A thin layer of gum arabic was added and allowed to dry.
Inking the plate
A container of clean water and sponge was prepared. Oil based relief ink was rolled up on the bench. Some water was applied to the bench beneath the plate to keep it in place. The plate was wiped with a damped sponge. A thin layer of ink was applied to the plate with a small roller. The process was then repeated building up the ink on the plate. The plate was then printed onto damp paper. Extra sheets of paper were place on top of the blankets to bulk up the pressure on the plate.
