I mixed up new collodion and silver nitrate, and apparently got this cosmic collodion! After a little trouble shooting I found that it was the collodion, or a small portion of it anyhow. I had mixed up a batch of John Coffer’s “Poe Boy” collodion and didn’t have one bottle large enough for the entire batch, so the last couple ounces of the mix went into a smaller bottle. It turned out that smaller bottle must have had some undissolved salts which left this dust storm look on my test plates.
The larger bottle seemed pretty good, but maybe a few spots. I may try to filter it to see if I can clean things up a bit.
While this image with the “cosmic dust storm” was a mistake, the effect is interesting.