Troubleshooting, or What the Hell Is That?

[goamules]

I'm worried that one day I may actually perfect this process.

Practice makes perfect. Most, but not all, will eventually be making very good plates. Perfection it hard to attain, There are about 37 steps to do that can all mess up a plate. I don't think I ever mastered all of them. Sandarac varnish for example, is very hard to make flawless. So I moved to synthetics. Tearing the emulsion with the dark slide can be overcome by very careful handling of the plate and slide, and having a good holder. But I still sometimes tear a small part, especially with old collodion. I guess that's the key: eventually you KNOW what is causing every problem. You just decide and triage which to work on, which to ignore.

[paulbarden]

The single change I made that led to near-perfect Sandarac varnish every time was: using a toaster oven. Prewar the plate at about 225F for 40 seconds, pour the Sandarac, drain, and return it to the toaster for 2.5 minutes or so. It’s so easy, and the results are almost always excellent.

[goamules]

Sounds good, I may try it. I know my main problems with Sandarac: not filtering the dust enough. I use a pour off bottle, but it seems you have to filter it even if it sits in a bottle for 6 months unopened. You also must varnish as soon as the plate dries. If you wait a day or two, pits. Other than that, most of my sandarac plates look good. And it sure lasts...I have one mounted outside on my porch that has been there about a decade. Still shiny and clear.

[pau3]

I started recently the slippery road to wet plate collodion. I studied some literature
(Jacobson's books and the Scully & Osterman Collodion Manual) and attended
a workshop to learn the practicalities of pouring, developing and varnishing.
After that, I began with my own trials, alone. I mixed my own chemicals, as I often
do with other processes. But the first ones were a complete failure. My plates were
completely fogged. Highlights seemed to appear correctly and, just suddenly, a veil
covered the whole plate. I started to change things, one at a time, after discarding
hardware failures. First, I changed the collodion formula, from Osterman's to Jacobson's,
without success. Jacobson's formula was the one I used in the workshop, so I was quite
confident that it should work, but still fogging appeared soon after pouring the developer, before 15 sec.
Highlights seemed to be ok, but everything else was fogged. So I focussed on the developer.
I changed the ferrous sulfate to a purest one, but the problem subsisted. Next, I thought
about the acetic acid. Instead of buying a new one, I kept using the one I have at my darkroom but
changed its quantity in the developer: instead of 4%, as it appears in Osterman's positive developer,
I changed to 6%, keeping the rest of the components equal. Et voilà, fogging suddenly disappeared
and everything was perfect.

I have two questions. I hope that people here with experience can answer them.

1)Is it normal that such a small change in the composition of the developer
have such a strong impact in the result?

2) It is not completely true that I changed only one thing at each step. Fogging appeared while
doing ambrotypes, but in the end I got tired of preparing them, so the successful test was done
on aluminium. Does this really matter, in your experience?