Another question about odd film development

[lex_jenkins]

<p>Bad batches of emulsion are very rare, but do occasionally happen.</p>

<p>So far I haven't encountered any defective b&w film emulsions, but did buy a box of Mitsubishi b&w RC paper that had extremely fragile emulsion. It was so fragile even the slightest touch on the wet emulsion caused scratches. I had to print with generous borders and handle the paper only by the edges.</p>

<p>Lisa, I'd suggest clipping a short length of the same film the students are using - 6-12" would be enough. Doesn't even need to be exposed in a camera for this test. Mix batches of the same chemicals they use. Use standard agitation. You can do all of this in the light, so you can see what's happening. See if you can reproduce the problem.</p>

<p>If you can't reproduce the problem, that would indicate the problem occurs somewhere else in the process. Perhaps someone used hot water *and* shook the tank like they're making a martini (I'm surprised by how often newbies think aggressively shaking is the correct technique, even though there are plenty of illustrated and video tutorials showing the correct technique). Perhaps the emulsion has been scratched in the camera or when handling in the dark, making the emulsion vulnerable to sloughing off when wet.</p>

<p>But try some test strips yourself to see if you can reproduce the problem.</p>

[craig_shearman1]

<p>Totally understand your frustration with this. What Larry said about quality control -- "there were some bulk rolls that were not as good with the Q.C. but that has been fixed and the Q.C. is now top notch" -- was what I was getting at, not intending to criticize your teaching. The non-Kodak/Ilford products are perfectly fine most of the time, but don't necessarily have the same quality control as products that go out under their own names even if they are coming from the same source. Glad to hear QC has improved.</p>