Glass Transfer "Varnished" Prints

I purchased this primarily for the frame, and when I got it home realized that it was a fairly good example of glass transfer of a print (I always called these "varnished prints" - I don't know if I saw the term somewhere or if that just came out of my head).

Basically, these were done by varnishing a print to the glass, removing most of the paper, and coloring/painting to add the color. The effect is of a reverse glass painting, or in this case, a faux painting on porcelain. I have seen many of these from the late 18th century, and this one I would date to approximately 1845 based on the lady's clothing and the frame.

Many of the earlier ones appear quite dark, as the varnish browned with age (and of course, many simply got broken, or replaced with something else if the varnished degraded to the point that the image was no longer attractive.

Here is a link to the blog on the website of The Philadelphia Print Shop, Ltd., in Philadelphia, where one of the owners discusses this art form:

http://antiqueprintsblog.blogspot.com/2009/07/glass-transfer-painting.html