If it seems to be no "rhyme or reason" then I would look to possible other mishaps. Film will respond to light in a consistent manner. Is there a problem with your Minolta shutter? Could there be a light leak in you gaffer tape tube. Or is there light reflecting off the inside of the tube.
Katharine Thayer wrote: > Chris Peregoy wrote: > I would try to get a > > better fix on your pin hole size. I use a comparator as described in > > Eric Renner's book, page 113 and 114 with the use of an enlarger to > > enlarge a metric scale. Then figure for reciprocity failure. I always > > try to make an accurate guess first with meter and calculations, then > > after gaining experience I can usually guess without these aids. > > > > I've done all those things, except for precisely accurately measuring > the pinhole, and even there I doubt that my estimate is all that far > off. I've done pretty well with my five other pinhole cameras, > estimating the pinhole size and making my way to a good guessing range > for exposures, with only one or two trial exposures in each case. The > point was that for this particular camera, even allowing a large margin > of error on my estimation of pinhole size, the range of exposure times > that would be predicted seems to be many magnitudes too long (even > without figuring in reciprocity failure) compared to the empirical data. > The question was, does anyone have any idea why that would be, and more > to the point, why there doesn't seem to be a logical function that I can > identify connecting the exposure times to how the negatives turn out. > After I could see that using the textbook rules wasn't going to get me > anywhere very fast, I started running exposure trials, taking the same > subject at 6 or 8 widely differing exposure times, taking careful notes, > but since there didn't seem to be any rhyme or reason to the results at > the end of a week or so, I decided I couldn't spend any more time on it > until after I get this show up. I just wondered if someone had a bright > idea I hadn't thought of. My first thought was that maybe there's > something squirrely about this film, but later I read in one of the > books that it's considered a good film for color pinhole, so I guess > it's not that. > Katharine Thayer > > _______________________________________________ > Pinhole-Discussion mailing list > Pinhole-Discussion@p at ??????? > unsubscribe or change your account at > http://www.p at ???????/discussion/ -- Chris Peregoy | http://www.gl.umbc.edu/~peregoy | http://imda.umbc.edu/
