Exposure 40 min, f/5,6 in wet plate collodion process?

[Tin Can]

https://youtu.be/J5c21-YVlTY

[paulbarden]

I wondered how long it would take before someone questioned Borut's recent vlog.

It was probably about 45F in that room during the exposure, which would have considerably slowed the drying of the plate. Another possibility (which wasn't presented in the video, so I suspect Borut didn't use it) is that at the end of a very long exposure, you can put the exposed plate back into the silver bath for a couple minutes before developing it. I have not tried this myself, but I have seen it mentioned several times in older literature, so I assume it's possible.

[Two23]

Apparently reciprocity isn't that much of a factor with wet plate. I once made a 10 minute exposure in cool damp weather, and placed a wet sponge inside my bellows near the tin.


Kent in SD

[Tin Can]

He is a real smart person with a very good education

He knows how to tease

I am tired of Patreon, so many hands out

So I stopped paying him and others

[Kiwi7475]

He may have exposed for 40 min but maybe the last 20 it was already dried. I doubt he re-dipped in silver half way because it’s almost impossible to get enough precision and not show up as a double exposure. He may have used a wet towel or alike (he’s talked about that in other vlogs), or simply exposed until it kind of dried such that it didn’t really expose it further. Maybe also it wasn’t 40min… perception of time is tricky… when I am waiting for something, 20 mins feel like 40…

[paulbarden]

He may have exposed for 40 min but maybe the last 20 it was already dried. I doubt he re-dipped in silver half way because it’s almost impossible to get enough precision and not show up as a double exposure.

RE re-dipping in the silver bath: I'm not talking about putting the plate in the silver bath and then back in the camera to make more exposure (surely that wouldn't work well, for the reason you state). I'm talking about re-wetting the plate at the end of the exposure to "wake it up again", which was described in some of the period manuals as an option when making very long exposures. I have not attempted this myself, but I have had some practitioners tell me it is possible.

[Kiwi7475]

RE re-dipping in the silver bath: I'm not talking about putting the plate in the silver bath and then back in the camera to make more exposure (surely that wouldn't work well, for the reason you state). I'm talking about re-wetting the plate at the end of the exposure to "wake it up again", which was described in some of the period manuals as an option when making very long exposures. I have not attempted this myself, but I have had some practitioners tell me it is possible.

I’ve heard that before and I’m intrigued as to how that would work. How’s it getting more exposure without… more exposure, even if you get it wet again?

[paulbarden]

I’ve heard that before and I’m intrigued as to how that would work. How’s it getting more exposure without… more exposure, even if you get it wet again?

Its not. That's not the point. The idea is to return the plate to the wet/active state in order to prepare it for introduction of developer. If a plate has dried before developer has been applied, then you get "dead" areas on the plate, ugly artifacts, etc. The reintroduction to the silver bath avoids that happening, or so it has been suggested. As I say, I have not attempted it myself because I have always kept exposure times under 15 minutes.
What's the longest exposure you've made, and did it result in dead areas/marks on the plate?

[Kiwi7475]

Its not. That's not the point. The idea is to return the plate to the wet/active state in order to prepare it for introduction of developer. If a plate has dried before developer has been applied, then you get "dead" areas on the plate, ugly artifacts, etc. The reintroduction to the silver bath avoids that happening, or so it has been suggested. As I say, I have not attempted it myself because I have always kept exposure times under 15 minutes.
What's the longest exposure you've made, and did it result in dead areas/marks on the plate?

Thanks— that makes sense, but then re-wetting doesn’t help towards making an even longer exposure; the limit is given by when the plate dries. My guess is that probably the scene he was shooting was maybe properly exposed at 15-20 min — or until it dried. But who knows (but him)?

I’ve also never gone over 8-9 min. Never had a reason to try longer; most of my collodion work is either outdoors , or if indoors I mostly use strobes.

[Bill Rolph]

Thanks— that makes sense, but then re-wetting doesn’t help towards making an even longer exposure; the limit is given by when the plate dries. My guess is that probably the scene he was shooting was maybe properly exposed at 15-20 min — or until it dried. But who knows (but him)?

I’ve also never gone over 8-9 min. Never had a reason to try longer; most of my collodion work is either outdoors , or if indoors I mostly use strobes.

Does the plate drying make it no longer light sensitive? I don't see why that would be the case. My understanding is that it only inhibits development.

[Kiwi7475]

Does the plate drying make it no longer light sensitive? I don't see why that would be the case. My understanding is that it only inhibits development.

In all the manuals I have and also if you google online, everything points to the fact that the sensitivity drops dramatically after the wet plate dries. From that perspective if it’s dry after say 15 min, for example, you won’t get much if anything at all in terms of exposure for the other 25 min. I can’t say I can explain the physics of why that may be the case, and I haven’t tested it myself, but that’s what I read.

Couple of places online that mention it (but don’t explain it):

https://www.photrio.com/forum/threads/dry-wet-plate-waiting-drying-after-collodion-and-silver-baths.135921/

https://annemariehopecross.com/photographic-processes/wet-and-dry-plate-collodion/

I’m sure there’s others out there that can chime in with the physical process going on and it’s impact to its sensitivity.