That's the advantage a corporation has: They can have engineers and testers work full-time on a project. Those of us doing this as a hobby in evenings/weekends take short-cuts. My short-cut has been to develop just once, and if all looks normal, accept that and proceed to the next test. Also, I have tight control over temperature, exposure, agitation, etc. to try to improve the chance that my first try will not have any anomalies. But your point is that there is still test-to-test variation, and only multiple tests will reveal the variation-ranges.
Originally Posted by Gerald C Koch
Do you have any ideas of how to get variation-ranges (error-bands) without tripling the amount of effort? Maybe if I make three runs of the most popular films, and just one of the others? Or three runs of anything that looks odd? Or maybe others could volunteer to share the tedious testing effort?