Last edited by jnantz; 9-Jan-2019 at 10:56.
In reference to original question, I am wondering how the color shift during warm up would effect wet plate. As I understand it, wet plate has extended UV sensitivity, and it occurs to me that there might be a duration during the warm up curve that not as much UV light is being emitted. This isn’t really a problem, just a consideration as the HMIs I worked with in college could take anywhere from a couple of minutes to 20 minutes to fully warm up in the visible spectrum. I wonder what the experience would be like if I could see on UV, does the UV out put warm up at the same rate? Perhaps someone here has experience using HMIs with wet plate? I think that’s what the OP is looking for.
Answer: flash bulbs.
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The amount of UV sensitivity wet plate has depends on the salts you use but the UV response is never what I would call significant. It's a common misconception. If you look at the work Lund has done to quantify the spectral response of collodion, you'll see that all the salts (iodides, bromides, lithides) produce mostly violet sensitivity. Depending on the salts used, some combos have violet plus blue and a bit of green sensitivity and some combos had violet response plus a VERY VERY near UV and a touch of blue. None had extended UV response. I suspect that the myth that collodion is mostly UV-sensitive arose because the printing methods that go along with wet plate negatives are UV-only and, being massively orthochromatic, wet plate such a "different than normal" look to it that people assume or are willing to believe that it sees only UV.
FWIW, I am using modern strobes to shoot my plates and they turn out well:
20181230-1.jpg by Ty Williams, on Flickr
Nice going Ty you've captured the subject as she gives something of herself to you. i've found the prior techno BS entertaining but this at least i think is the proper end result regardless of how you got there.
j
Thanks! And appreciate you sharing your experience with shooting continuous light... I understand that stobe is what's usually used, but am interested in experiences of others who have used hmi's or other continuous light at high power and low shutter speeds.
And I'm pretty well versed in strobes and what they can do, so to reiterate interested in continuous! Or comparisons to strobe at the least!
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I suppose the best point of reference would be to cast back to the work done in the 1860's to 90's Where they was no strobe and slow film, the solution daylight, plenty of it, using blinds to shape the light. Hence the style of portraiture which was informed by the shutterspeeds. That and the fact the sitter has to keep still when you are using large format.
I would suggest that plan A would be to use daylight plan B go for HMI, the problem with hot lights is the wavelenght of the light. If it helps I have been using ilford gallerie gr 2 paper negs rated at 6 ISO deved in rodinol and they work perfectly. Shooting with both strobe and daylight I found the most consistant resuts were on strobe, which is to be expected though the quality of diffused daylight produced a better tonal range which was a lot easier to print.
Why not try a combination?
Strobe and continuous light with a long shutter
Tin Can
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