Category: WW I History

Invisible Photography and Writing

A small four page booklet, entitled Invisible Photography and Writing, Sympathetic Ink, appears to be the result of testing, by the chemist at the U.S. Bureau of Standards. The information, was produced by a hand writing expert, out of San Francisco, CA, by the name of Theodore Kytea(?). The booklet states it's "Confidential and Not for Publication".