Sustainable Printing

The next big revolution in printing came along quite by accident.  Although lithography had been on the scene since the late 1700s, it wasn’t until Ian Rubel made a mistake that printing would become “offset” over 100 years after lithography was first introduced.

Lithography was the first type of printing that was a chemical process.  Instead of raised type (like with letterpress or stereoplates) where the ink was rolled on top of the text and then stamped onto the paper, lithography used limestone plates to transfer an image drawn with a greasy substance.  Because limestone is water-absorbent, water would first be rolled over the entire stone.  The image would repel the water and the non-image areas would absorb it.  Then an oil-based ink was rolled over the surface, and since oil and water don’t mix, the ink would only hold to the image to be printed.  Once this was done, the image was then transferred to paper.  Below is a lithographic stone plate on the left with the negative image and its printed positive image on the right.

Offset lithography uses the same chemical process, but has an extra step in involved.  When Ian Rubel was operating his lithographic rotary press, he discovered that if he failed to insert the paper in between the rubber impression cylinder and the printing plate, the image would stick to the cylinder and then print on the back side of the paper.  What’s interesting is that the image coming from the rubber cylinder was quite superior in quality and the “original” would last longer than printing directly from the plate.  Hence, the image was “offset” from the plate to the cylinder for printing.

This allowed for higher quantity runs, sharper images and got rid of having to reverse (mirror) the original images.  This process is still in use with today’s offset printing, but because of all the chemical compounds needed, the production of plates and other issues the environmental impact has become quite the concern.  I will explore these topics more thoroughly in future posts.

Photo Credit:  The above image was downloaded from Wiki Commons - click on the image to be taken directly to the download site.

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