At 03:13 PM 1/10/2008 -0800, you wrote:
These figures look more realistic. Early strobes used higher voltages and achieved shorter flash durations however this resulted in short duration reciprocity failure, leading to colour imbalance with colour emulsions and underexposure with BW emulsions. Modern flashes use larger capacitors with longer discharge times leading to a safer and more usable product.My memory is that Bron flashes can still do very short duration stuff. All the best Laurence Cuffe All the best
Just for the heck of it I did a Google search on reciprocity failure and by far the most citations were for long exposure, but there were some for short exposure failure.
There are even Kodak sites with correction values and recommendations for minimum exposure times for various Kodak films.
Bottom line, however, is that emulsions were changed some time back to better handle the short duration failures, and of course, as mentioned above, strobe flash durations have become longer with larger capacitors.
On this same subject, Carlos mentions that he still uses a Vivitar 283, and I do also. Mine is very-very old, and has the high-voltage high-current trigger for the flash contacts and I feel sorry for the contacts every time I use it. There are low level adapters but since nothing in a camera has failed yet I just continue to use my old model.
DAW
