This thread has developed into an interesting discussion.
However, all I can add is:
1) "Kevin and Angela's most excellent Ysart website" refers to my article [edited by Angela Bowey] Identifying Paul Ysart Paperweights
within Angela's glassmuseum website: http://www.theglassmuseum.com/ysart.htm
If my memory is correct, the article was published in 2000.
2) I did, indeed, use the term "Reddish Green" in the section for Ultraviolet Light Tests
. See the article details for full context. It was the best description that I and Terry Johnson agreed on when viewing the fluorescence of the those particular items. It was intended not as a description of a specific colour in its own right but as an indication of what we saw under the conditions of the testing.
3) The "Reddish Green" that we noted may have been caused by a mixture of green and red in proportions that looked to us to be "green with a definite hint of red". If that was true, I have no idea why there should have been a mix of two fluorescent colours visible. But the colour we saw was not a plain green, although it was a darker rather than lighter shade, and it was certainly not an obvious red.