Monday, October 18, 2010

Imprint knowledge part two Lithography


Lithography has many processes within itself, paper plate lithography, stone lithography, plate litho, and polyester plate lithography, just to name a few. I thought I would run through a couple and review the structure that of all of them stand on.

All lithographic technology is based on the simple principle that oil and water do not mix.
Paper plate lithography (also know as xerox lithography, if you hear xerogrpahy they are trying to sound more than they are) is the easiest technical explanation of this premise.  
When put through a laser printer (a printer with toner rather than ink) the colored powdered plastic we call toner covers the paper in whatever image we choose. The plastic toner is melted onto the paper sealing one side of the paper in whatever your image choice is.
The paper is then wet with gum arabic and water. (Gum arabic and the paper are both hydrophilic (they love water)). 
The print inks used in this process are oil based. So with the paper soaking in some of the water and the toner repelling water due to it being plastic. The ink is rolled over the whole sheet of paper and will only stick to the toner.  In this way you can print up your paper plate in any color of your choice. (seen below is one in process)

The paper plate is then run through the press with dry or damp paper to come out with the print.
example of lithographic limestone
All lithographic processes are similar at base, some are done on stone, some on steel plates, they can be based in drawing or in photography.  It is one of the most challenging technical processes in printmaking but also one of the most rewarding.

Paper being pulled off stone after printing.

The following are examples of Stone Lithography from one of the masters Oldrich Kulhanek

 I got to see this in person as a student at The University of Florida and it was one of the reasons I pursued stone lithography as a focus for almost 5 years.   His work is also the first image you see in this post.

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