Who were Sir John Herschel's blue test subjects?

Earlier this year, in my newsletter about the possible origins of the pornographic connotations of the color "blue", I mentioned that it was quite odd that the only images I could discover by the invention of the cyanotype, noted astronomer and scientist Sir John Herschel, were images of young women.

After more research, I would like to walk back any suspicion of innuendo or impropriety. That said, it seems that Sir Herschel was somewhat of a trendsetter.

Oxford

This past month, I made a special visit to the archives at the The History of Science Museum in Oxford, where a very friendly curator graciously gave me access to view Sir Herschel's photographic archive, even though I would not stop sharing random tidbits about color.

As I looked through his experiments, I began to see a pattern that he had tested the same image with numerous different chemical solutions and combinations.

Copy Machine

We often speak of John Herschel and his cyanotype in the same breath as we mention the photography Henry Talbot Fox or Louis Daguerre.

It's for a very good reason, because strictly speaking, Herschel was experimenting with photography, ie. drawing using light. Just not in the same sort of photography that the others were. The cyanotype is more akin to the mimeograph or photocopier. Blueprints are literally just copies of the originals.

Engraving

Moreover, upon having more versions of the images, it became clear that I was as guilty of this misunderstanding as the next person. These images were not capturing snapshots of life, they were replicating the work of a human engraver, who copied works from paintings for print.

Using some truly horrible pictures I took using my phone, I searched through various archives to try to identify the original works. And I was successful in identifying some of them, including one that Wikipedia identifies as an "Experimental cyanotype of an unidentified engraving of a lady with a harp".

(I'm not going to fix the Wikipedia page, on principle, as I don't believe that researchers should be updating encyclopedias. However, if you are convinced, feel free to update it.)

Friendship

At first, I theorized that Herschel was friends with the engraver, because Henry Wood, one of the engravers, later created the engraving for one of Herschel's portraits. But as I went down the rabbit hole, I discovered that the answer is a lot simpler.

Herschel didn't have a penchant for creating images of young women. But in one of the annual publication of "Friendship's Offering", which has a lovely melange of stories and poems, and quite a few engravings of young women who are either forlorn or lost in thought, I was able to find able to find several of the engravings he experimented with. What's more is that I found additional engraving he copied in other issues of the same yearbook.

It's very possible Herschel enjoyed fiction, he was a polymath after all, and those people are known for their sense of whimsy. Or so I'm told. More likely, though, his wife did, and he ran his photographic experiments with her books. But who could know?

In his additional defense, I will also say that his experiments with the portraits of young women tended to be a lot more successful than the other pictures, like the landscapes he attempted to replicate.

Blue Photography

A similar story is told about the researchers working on digital image compression research at the University of Southern California, which led to the invention of the JPEG. However, they chose the centerfold model from the November 1972 issue of Playboy, a Swedish model named Lena Sjooblom.

Two reason was stated in "A Note on Lena" by David C. Munson. First, the Lenna image contains a nice mixture of detail, flat regions, shading, and texture that do a good job of testing various image processing algorithms. It is a good test image! Second, the Lena image is a picture of an attractive woman.
Lenna 97: A Complete Story of Lenna