Sal Santamaura
Member
Thanks for pointing that possibility out. I did use it intentionally. Since it hadn't been quoted, I didn't even consider it as a possible "transgression."I suppose it was the colloquialism you used: "You done good."

Thanks for pointing that possibility out. I did use it intentionally. Since it hadn't been quoted, I didn't even consider it as a possible "transgression."I suppose it was the colloquialism you used: "You done good."
My tests showed that diameter of the feed roller affects only how broad the area on either side of resulting film "kink" is, not the magnitude of maximum displacement away from flatness. Narrower rollers confine the transition area on either side of a kink to fewer mm; larger rollers spread it out of more area....Seriously, I suppose the rationale was that the bend would be so sharp as to fit between frames.
After discovering the problem, and while hoping to find a camera system that didn't suffer from it, I borrowed a friend's 500C and A12 to include in my testing. Unfortunately, film bulging was even worse than the other cameras then in my possession.Can anybody point me to any studies done on the bend-and-set situation in a Hasselblad? Certainly at first thought, they must be a terrible offender on that...
After reviewing my notes on this from the late 1990s, it seems there's another typo. Should be "as little as 15 seconds."...In my tests, depending on ambient temperature and humidity, it can happen in as little as 15 minutes...
Substantial bulges with both cameras' holders unless the skip-every-other-frame approach is taken.what about the Mayiya RB67 and the M645. There the film is basically doubled back over a 6 mm roller.
In that case, the film was held between the pressure plate in back and the Reseau plate in front.Well, I suppose the definitive input on this subject might come from the technicians who handled the returned film from the moon missions.
Well, I suppose the definitive input on this subject might come from...
In that case, the film was held between the pressure plate in back and the Reseau plate in front.
Nope, the Reseau plate was not "some distance" from the film. It was doing its intended job keeping things flat despite the reverse-curl-feed-roller-induced bulges.I don't think so. They wouldn't have risked newton rings like that. Surely, the etched glass was some distance from the film.
Note that this was before the days of Acros, TMAX 100 and Ektar with their glossy emulsions. Ektachrome's rather dull emulsion surface had no danger of creating Newton's rings.
Also, does the 70mm back induce the same curl?Nope, the Reseau plate was not "some distance" from the film. It was doing its intended job keeping things flat despite the reverse-curl-feed-roller-induced bulges.![]()
As I understand it, a polyester base was more dimensionally stable, and being very resistant to breakage could be made thinner to allow more pictures per roll.And Kodak was a space contractor, so you can be sure they had tested things out thoroughly, they also had to make a special batch of film for space as the normal Acetate base apparently does not like to live in a vacuum, and so NASA needed Polyester film.
Sorry, I've never seen a 70mm back, so don't know. However, it seems unlikely that it would feed directly off a supply spool into the exposure area without making a bend, so the answer is "probably."Also, does the 70mm back induce the same curl?
Substantial bulges with both cameras' holders unless the skip-every-other-frame approach is taken.
That is the aforementioned Reseau plate.The Blads on the moon had (still have) a graticule plate which would have helped like the Rollis.
He stated that causes for their financial trouble were the reduction of toll-manufacturing orders by their clients as well as failed attempts to gain investors for new projects.
I'm curious. Do you know what are (or were) the toll items that they manufacture for other companies?
Ken
Trimble Navigation and Impossible Project to name a photographic and a non-photographic client.
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