What the heck is a hectograph?

According to the local paper, the school board of the West Riverside School purchased and installed a Ditto machine at the school on December 7th. It was taking the place of a hectograph. I know what a ditto machine is, or was, but I had never heard of a hectograph. 

I found information on the hectograph on www.officemuseum.com. That website said that in the hectograph process, introduced around 1876, a master was written or typed with a special ink. The master was then placed face down on a tray containing a layer of gelatin and pressed gently onto the gelatin for a minute or two. This allowed most of the ink to transfer to the gelatin. In order to make a copy, a piece of blank paper was placed on to the gelatin and a roller used to press the paper onto the gelatin, making each copy a bit lighter than the one before. Supposedly up to fifty copies could be made from one master.

 

The spirit duplicator, or Ditto machine, was introduced in 1923. It used a solvent to wet the ink to allow for transfer of ink from the master to blank paper. Thus the addictive smell those of us of a certain age remember from the dittos our teachers handed out to us in our youth.