One thing I hear about tintype from time to time, from people who reasonably ought to know better (and in one recent, who then went on to immediately prove himself wrong) is that a tintype is a "unique object" and "can't be duplicated the way a negative can."
This is a patently absurd statement -- even a daguerreotype can be rephotographed, though the lighting needed to show a dag image and still produce reasonable exposure times is somewhat tricky to set up. Tintypes, on the other hand, are much faster than dags and have much higher contrast at non-optimal angles. Obviously, rephotographing to any size plate you can coat, expose, and develop is not a huge big deal.
On the other hand, if I want to make, say, a 16x20 copy of one of my (so far, hypothetical) 4x5 tintype plates by this method, I'd need to have a 16x20 camera, at least improvised, and a lens that will cover 16x20 when focused for a 4:1 image size (which is much less of a problem than covering that size at infinity, at least).
It seems to me an opaque projector, built as an enlarger, would hold the answer for this -- a plate could be simply laid on the enlarger base board, the the plate to be duplicated projected with a strong, high-UV light source, suitable exposure given, and the plate developed as usual.
Potential problems are heating and UV damage to the coating of the original plate, long exposure times with continuous light (potentially solved by using continuous light to focus but high powered strobes, possibly multiple firings, for the actual exposure), and the usual issues of coating, sensitizing, and processing such a large plate.
Still, those don't seem like much larger roadblocks than wet plate photographers deal with on a routine basis -- highly flammable and potentially toxic materials, for instance, short working time for the entire process between coating and setting the plate to dry, and so forth. Yet, tintype photographers seem to act as if they're unaware of this as a possibility. Why is this? What am I missing?
This is a patently absurd statement -- even a daguerreotype can be rephotographed, though the lighting needed to show a dag image and still produce reasonable exposure times is somewhat tricky to set up. Tintypes, on the other hand, are much faster than dags and have much higher contrast at non-optimal angles. Obviously, rephotographing to any size plate you can coat, expose, and develop is not a huge big deal.
On the other hand, if I want to make, say, a 16x20 copy of one of my (so far, hypothetical) 4x5 tintype plates by this method, I'd need to have a 16x20 camera, at least improvised, and a lens that will cover 16x20 when focused for a 4:1 image size (which is much less of a problem than covering that size at infinity, at least).
It seems to me an opaque projector, built as an enlarger, would hold the answer for this -- a plate could be simply laid on the enlarger base board, the the plate to be duplicated projected with a strong, high-UV light source, suitable exposure given, and the plate developed as usual.
Potential problems are heating and UV damage to the coating of the original plate, long exposure times with continuous light (potentially solved by using continuous light to focus but high powered strobes, possibly multiple firings, for the actual exposure), and the usual issues of coating, sensitizing, and processing such a large plate.
Still, those don't seem like much larger roadblocks than wet plate photographers deal with on a routine basis -- highly flammable and potentially toxic materials, for instance, short working time for the entire process between coating and setting the plate to dry, and so forth. Yet, tintype photographers seem to act as if they're unaware of this as a possibility. Why is this? What am I missing?