Question regarding varnishing of wet plates

[Bill Rolph]

I made my first successful wet plates on glass today, and after drying went to varnish them. However, pouring the sandarac varnish on to the heated plate just basically washed the image right off. What did I do wrong? Not dry enough? Did I not clean the glass well enough beforehand? Or is it something else entirely? Thanks for your time. Also, if this is the wrong place for this thread, let me know and I'll move it.

[paulbarden]

Hello Fagrid.

If the Sandarac dissolved your collodion image, its because the collodion was too old. So it would be important to know the age (and source) of your collodion. Salted (mixed) collodion lasts about a year at most before the nitrocellulose breaks down and becomes too weak to withstand exposure to alcohol (in the varnish). You can still makes plates with old collodion, but you'd need to finish the plates with a synthetic/acrylic varnish.

[Bill Rolph]

It is indeed about 9 months old. Thanks so much.