Wet Plate Collodion questions answered here.

[shelby_wright]

A few questions I have:
1. What is the optimal time for the silver nitrate bath? I've done four minutes each time, but maybe there's a problem here? I have very little silver nitrate to work with, I only ordered 10g because its so expensive, so my bath barely submerses the plate without constant movement of the container.
2. Am I supposed to be washing the plate off after the silver bath? I haven't done so at all, and even though I tap the plate a bit over the bath to get most of the liquid off, its still wet with a little silver nitrate mixture when I put it into the camera and during the exposure.
3. How long is the fixer stage supposed to last? I have been putting the plate into the developer for about 35 seconds (it says 30-40 seconds at 70°F on the bottle), washing it off, then putting it into the fixer for anywhere from 15 seconds to a minute. I have read that it is supposed to be until the image appears, but of course none do.

Those are about all the questions I can think of at this stage, I know there are calculators for exposure time, but they aren't very useful for me since I have no way to measure light level or any specifications for the lens I am using (ridiculous I know, but that's what a mysterious $7 eBay lens gets you).

Once again, any comments, advice, or anything to know I'm not typing into a void would be much appreciated . Also, would this be better posted as a separate thread about my cardboard adventure? I'm afraid to violate any unspecified etiquette, I have only ever lurked on forums before.

1) The rule of thumb is around 3 minutes at 20C - longer if it's colder, can go shorter if it's hotter. In general it doesn't really matter if you leave it in longer. Agitating it the way you are will speed up the sensitising.

Something I didn't see you mention is whether you iodised your bath before using it - you need to put a glass plate coated in collodion in it overnight. I may be misremembering this, but I think the reason is because otherwise an unseasoned bath will suck all the iodides out of the collodion on the plate you're taking an image on, and you won't get much.

Because you are using such a small bath I would not use a whole plate though, I'd coat a small piece of glass (maybe 25cm² or less). Don't use trophy aluminium because having it in your bath overnight will do bad things to it.

I know silver nitrate is expensive but you are making it extra difficult for yourself using such a small bath relative to the size of plate. Any problems with your bath such as excess solvents, contamination, or particulate matter are going to be magnified and immediately apparent, there will be much less margin for error. You'll also find it harder to get consistent results with each plate taking up a comparatively greater amount of the available silver, meaning you'll need to maintain and replenish it more often.

You can build a vertical tank for 4x5 out of a memo water bottle (hacksaw off the top), and some cardboard and duct tape for lightproofing - it's what I've used for years.

2. On the contrary, you want to dry it off as best you can. Put each edge down on a paper towel and let that wick away a bit of the remaining silver nitrate solution, then dry the back. The less silver nitrate floating around in your holder/camera, the less likely you'll see artefacts from contamination. However, washing/not washing it would not lead to the global failures you're seeing in your plates.

3. Fixer depends on how many plates you've run through it already (some people like to use it one-shot, personally I don't want to deal with disposing of that much fixer). I use sodium thiosulfate at around 20% concentration by volume and a plate typically clears in 10-60s or so depending on how much I've run through it that day and how recently I've topped it off with fresh stuff. At any rate it's not really possible to overfix with sodium or ammonium thiosulfate, so that won't be your problem.

Collodion is notoriously hard to meter for due to how the chemistry ages and how it perceives light differently from our eye/a standard meter, but that doesn't mean a meter isn't useful.

If you had a normal film holder (or found a way to integrate a darkslide into your camera), you could do a test plate where you push the dark slide in at 20% increments for exposures of 2 (all the way out), 2, 4, 8, and 16s (final 20%). The resulting plate will show you what exposures look like at 2, 4, 8, 16, and 32s. If you take note of the EV values when you shoot your plate, you can then adjust as the light changes. Unless I was shooting the previous day and have readings to go off of, I start every shoot by doing this. Today I got an exposure of 5s @ f/16 with a meter reading of 12EV in the shade, and as the sun came out (and later was hidden by clouds) I could adjust as I went. Trying to develop by inspection is something everyone sees the experts doing in YouTube videos and tries to emulate, but it just adds another unecessary variable to the process and creates more problems for most people starting out. You're doing the right thing by holding development time constant, stick with the instructions.

I have a feeling that lens probably lets in a fair bit of light (and doesn't have a way to close down the aperture and let in less), so in full sunlight you may need to use shorter increments than I described above, like maybe 1/2s, 1/2s, 1s, 2s, 4s.

If you'd like some free reading, Will Dunnaway's widow has posted his collodion handbook online for free: https://www.alternativephotography.c...Plate7-web.pdf

Christopher James (who wrote the Book of Alternative Processes) has a chapter on wet plate, which also happens to be one of the ones he offers for free as a sample: https://static1.squarespace.com/stat...on-Process.pdf

But definitely keep posting your results and questions here too!

[paulbarden]

Hello again. I tried implementing some changes with my process.

A few questions I have:
1. What is the optimal time for the silver nitrate bath? I've done four minutes each time, but maybe there's a problem here? I have very little silver nitrate to work with, I only ordered 10g because its so expensive, so my bath barely submerses the plate without constant movement of the container.
2. Am I supposed to be washing the plate off after the silver bath? I haven't done so at all, and even though I tap the plate a bit over the bath to get most of the liquid off, its still wet with a little silver nitrate mixture when I put it into the camera and during the exposure.
3. How long is the fixer stage supposed to last? I have been putting the plate into the developer for about 35 seconds (it says 30-40 seconds at 70°F on the bottle), washing it off, then putting it into the fixer for anywhere from 15 seconds to a minute. I have read that it is supposed to be until the image appears, but of course none do.

Those are about all the questions I can think of at this stage, I know there are calculators for exposure time, but they aren't very useful for me since I have no way to measure light level or any specifications for the lens I am using (ridiculous I know, but that's what a mysterious $7 eBay lens gets you).

Once again, any comments, advice, or anything to know I'm not typing into a void would be much appreciated

My first thought is: I wonder if euli knows that the silver bath has to be replenished regularly, by adding more silver nitrate crystals? If you have bought only 10 grams and it made barely enough solution to cover a plate, then you are very quickly going to exhaust that tiny amount of silver unless you are replenishing the bath. I know AgNO3 is expensive, but this is one aspect of wet plate photography you can't "cheap out" on - if you don't have a well maintained silver bath, then none of the other details matter. You're going to have to invest in more silver nitrate if you're going to succeed at this and there's no getting around that.

Your other questions....
As Shelby said, three minutes in the silver bath is average. Less time if the environment is warm (80F or more) and longer if it's cold (50F or less). The time in the bath isn't critical as long as you aim for 3 minutes or so.

No, you are NOT supposed to wash the plate after you take it out of the silver bath. Just let it drain, and wipe off the back of the plate. Whatever you do, DON'T touch the front (collodion side) of the plate!

If you are using a rapid fixer, then fixing time is 2X as long as the minimum time it takes for the cloudy/blue has cleared from the plate. Fixing time isn't critical as long as you properly clear the plate.

About your lens: there is absolutely nothing marked on the lens to indicate its focal length or aperture value?? Without that critical detail, you are just guessing, and that's not helpful. I gotta say, though I admire your creativity in terms of making your own camera, etc., you are also making this process very difficult for yourself by leaving crucial details blank. But if you persist, you will likely start getting images on your plates. But controlling the variables and getting any kind of consistency is going to be difficult.

If you can find your way to spending some more money on this project, I recommend two things - one is mandatory and one is semi-optional. First, you're going to have to buy more silver nitrate. There's no escaping this fact. You'll need to replenish the silver bath (I'm betting you're close to using up the 10 grams you've got), and you should be using a hydrometer to measure the silver concentration. (Ideally you want to maintain a specific gravity of about 1.074).
As stated in the Dunniway manual:

"Before using any new silver bath you will need to purchase a hydrometer . (Beer and wine making stores sell them as well as labware supply houses .) This hydrometer will test
for the specific levels of gravity in your new solution. In other words, how much silver
is in your bath . To start, you will need to add your new silver bath solution to the glass cylinder beaker supplied with the hydometer . If it is not supplied, you will need to buy
a glass beaker deep enough for your hydrometer to float in. Now pour the new bath up to the mark at the top of the glass beaker . Then slowly lower your hydrometer into this measured bath solution. Make a note at what mark the hydrometer levels off at. This mark on your hydrometer will always be your reference point when you need to add new silver solution to any used silver bath . This is in order to bring it back to the 9% silver solution that is desired in the wet plate collodion process."

Typically, a 9% AgNo3 solution has a specific gravity close to 1.074, and you need to maintain that concentration or you will have great difficulty getting consistent images.

The second recommendation is: buy a lens that has a known focal length and (much more important) a known aperture value. That way, you can at least start to use a light meter (figure out how to measure light for 1 ASA) and then you won't be guessing anymore - you will have actual data to work with.

One other thing that bears mentioning is about development times. I look at the plates you've shown here and if the plate has not received any exposure, the plate should be clear (black) after the fixing bath. That bottom photo of the bluish plate tells me that either the plate is getting fogged in-camera, or you are overdeveloping the plate, which will cause unexposed silver to develop out. (Yes, that happens. It's not like film at all) Or maybe it's both. Only a lot of testing will reveal which problems you're seeing and separate them from each other.

Study that Dunniway document. If the only literature you have to work with is the Bostick and Sullivan instructions, you are working from a very spare document that offers only the bare bones of instruction. If you decide to get serious about wet plate collodion work, a complete tutorial manual is essential. John Coffer's "Doer's Guide" is considered the best and most complete manual, but Quinn Jacobson's "Chemical Pictures" is also very thorough. But start with the Dunniway document - it has a lot to offer.

[paulbarden]

@euli: any progress on your wet plate technique?

[ueli]

But definitely keep posting your results and questions here too!

@euli: any progress on your wet plate technique?

Thank you again for the suggestions and interest. Thank you in particular for the suggestion to iodize my silver bath, I had never heard of that part of the process in all my research. I did that with the suggested size of glass plate and now all my further exposures have been done using an iodized/sensitized silver bath. I also got some more silver nitrate, the 10g really wasn't enough. I have also taken into consideration trying to use a 'real' camera, like a Kodak 3A if I could find one for fairly cheap. I have also read through some of the documents that were suggested, and will continue to look through them.

I have made a few more exposures, and I think I may be getting closer to a successful one. What I got was more helpful than previous experiments have been. I used a second lens that I had gotten with the first, it seems to be part of a set, once again with no helpful parameters printed on it except for 'TELEPHOTO LENS' on the side. I had made a second box camera for it exactly as I made the first one, just with a smaller distance between the lens and plate of four inches instead of six. The aperture is a little smaller (still completely open) so I have a little more margin for error with the exposure time than with the other lens. Two exposures were taken with this lens in as similar conditions as I could manage, just a few minutes apart. One was exposed for half of a second, the other for five seconds. Everything else was kept the same as best as I could manage. It is clear from the exposures (at least it seems to be) that the correct exposure time would lie somewhere between these, as one is completely underexposed and the other completely overexposed. This seems like a much more reasonable margin than with the previous camera, where even my fastest times were far too bright.

Here are the two exposures I made with the telephoto lens.



above: The top plate is the half second exposure, the bottom is the five second one. Both were taken in a slightly cloudy environment.



above: The view through the camera of what it was trying to capture.


I also tried with the first lens and camera two more times, and again got results that were probably not that helpful. There may be a sort of outline of the statue in one of the exposures, but it could just be a random remnant of the process. This exposure was made in direct sunlight for half of a second.

Here is that exposure and what it was trying to capture.



above: Six inch camera plate exposed for half of a second in direct sunlight.



above: View from the position of the camera, there is a somewhat similar outline to what is seen in the final exposure: near-success or Marian apparition?

I've thought up a couple more questions during my experimenting:
1. I had an idea for a cardboard disk (Cheerio shaped) that I could place inside the camera against the lens in place of an aperture, does this seem like it might work? It would function somewhat like a pinhole camera by limiting what amount of light can go through the lens. I don't actually know how an aperture works, just how it looks, and this seems to mimic that well enough. Any idea what aperture size would be most helpful in the process of getting a successful exposure?
2. I have access to a few old DSLR lenses, would using one of these in the same manner as my mystery lenses be at all reasonable or possible? I would at the very least know a little more of their specifications than I do the mystery eBay ones.
3. Any suggestions for good ways to clean off failed exposures? I am using trophy plate aluminum and have now gotten through all 14 of the plates I ordered. I sealed one for practice but left the others.
4. I have noticed that many of the plates begin to peal after I leave them to dry overnight. Is there a good sealing technique to prevent this? I have some spray gloss sealant that I used on my first exposure after it dried. It made it a little murkier, but it never pealed. Is this a reasonable process?

Thanks so much for all the help, I really hope I can post a successful exposure soon!

[paulbarden]

Thank you again for the suggestions and interest. Thank you in particular for the suggestion to iodize my silver bath, I had never heard of that part of the process in all my research. I did that with the suggested size of glass plate and now all my further exposures have been done using an iodized/sensitized silver bath. I also got some more silver nitrate, the 10g really wasn't enough. I have also taken into consideration trying to use a 'real' camera, like a Kodak 3A if I could find one for fairly cheap. I have also read through some of the documents that were suggested, and will continue to look through them.

I have made a few more exposures, and I think I may be getting closer to a successful one. What I got was more helpful than previous experiments have been. I used a second lens that I had gotten with the first, it seems to be part of a set, once again with no helpful parameters printed on it except for 'TELEPHOTO LENS' on the side. I had made a second box camera for it exactly as I made the first one, just with a smaller distance between the lens and plate of four inches instead of six. The aperture is a little smaller (still completely open) so I have a little more margin for error with the exposure time than with the other lens. Two exposures were taken with this lens in as similar conditions as I could manage, just a few minutes apart. One was exposed for half of a second, the other for five seconds. Everything else was kept the same as best as I could manage. It is clear from the exposures (at least it seems to be) that the correct exposure time would lie somewhere between these, as one is completely underexposed and the other completely overexposed. This seems like a much more reasonable margin than with the previous camera, where even my fastest times were far too bright.

Here are the two exposures I made with the telephoto lens.



above: The top plate is the half second exposure, the bottom is the five second one. Both were taken in a slightly cloudy environment.



above: The view through the camera of what it was trying to capture.


I also tried with the first lens and camera two more times, and again got results that were probably not that helpful. There may be a sort of outline of the statue in one of the exposures, but it could just be a random remnant of the process. This exposure was made in direct sunlight for half of a second.

Here is that exposure and what it was trying to capture.



above: Six inch camera plate exposed for half of a second in direct sunlight.



above: View from the position of the camera, there is a somewhat similar outline to what is seen in the final exposure: near-success or Marian apparition?

I've thought up a couple more questions during my experimenting:
1. I had an idea for a cardboard disk (Cheerio shaped) that I could place inside the camera against the lens in place of an aperture, does this seem like it might work? It would function somewhat like a pinhole camera by limiting what amount of light can go through the lens. I don't actually know how an aperture works, just how it looks, and this seems to mimic that well enough. Any idea what aperture size would be most helpful in the process of getting a successful exposure?
2. I have access to a few old DSLR lenses, would using one of these in the same manner as my mystery lenses be at all reasonable or possible? I would at the very least know a little more of their specifications than I do the mystery eBay ones.
3. Any suggestions for good ways to clean off failed exposures? I am using trophy plate aluminum and have now gotten through all 14 of the plates I ordered. I sealed one for practice but left the others.
4. I have noticed that many of the plates begin to peal after I leave them to dry overnight. Is there a good sealing technique to prevent this? I have some spray gloss sealant that I used on my first exposure after it dried. It made it a little murkier, but it never pealed. Is this a reasonable process?

Thanks so much for all the help, I really hope I can post a successful exposure soon!

I'll start with this: 1/2 second in sunlight isn't enough exposure to get an image. That's just development artifact you're getting on your plates, not an image.

Don't guess - make a test strip plate, or you will just waste more materials.

You can scrub off collodion from failed plates with water, as long as you have not allowed the collodion to dry. If it has dried, you will need to use Ether to remove it.

[AgNO3]

Hello everyone who sees this.
I've just shot my first three 4x5 wet plates, with odd results.

I used a custom built camera for this, which is just a cardboard box I glued together with dimensions of 4"x5"x6" and a plastic lens I bought on eBay glued to the front (see attached pictures). I also wrapped the back in black fabric once I had inserted the prepared plate, so I am confident that the light only enters through the lens. I glued the box to my tripod mount (hot glue so I can take it off when I'm done playing with it), so the camera was as close to a real large format camera as I could manage on a budget of $7 and a spirit of perseverance.

The first exposure was a success in my opinion, I could at least tell that it was working (which was unexpected). The first plate was exposed for about three seconds with two tripod mounted (with fencing wire) flashlights and an old DSLR flash serving as lighting. The second and third exposures were both confusing failures. The second was exposed for 30 seconds the same lighting conditions. The third was exposed for one second with the same two flashlights but no flash. Both of these latter two exposures came out completely black with very slight markings on them, but no clear indication that anything was actually captured like was present in the first one.

I am unsure how the second and third exposures could be so similarly wrong, as the only difference between them and the first exposure was time and lighting, which are of course important but I would expect to have gotten some more informative data from these exposures rather than nothing at all.

Here are some images of each of the three exposures.

Attachment 251954 Attachment 251953
above: The first exposure with the shape of the lens just barely visible, highlighted in red. (3 SEC., FLASHLIGHT + FLASH)

Attachment 251955
above: The second exposure, completely black with no signs (in my untrained eyes) that anything happened. (30 SEC., FLASHLIGHT + FLASH)

Attachment 251956
above: The third exposure, similar to the second as far as I can tell. (1 SEC., FLASHLIGHT)

Here are some images of the camera itself.

Attachment 251960
above: The inside of the camera as seen by the plate (hopefully). I don't fully understand how a real large format camera would work, I know this is a very simplified version of one but hope that I could get some somewhat legible exposures with it. You can see this profile was captured slightly in the first exposure.

Attachment 251958
above: The plate is loaded into the back of the camera and held with a pushpin and blind overconfidence.

Attachment 251959
above: The loading hatch is then closed and held there with a rubber band. The opening was originally intended to be the loading mechanism, but I ditched that idea.

Attachment 251957
above: The camera when fully prepped. The black fabric is placed around the back and held with sewing pins to keep it tightly wrapped so light can't get in.

I am a little confused! I didn't change the chemical process at all between the first exposures and the next ones, but the image doesn't come out at all the second two times... why? When creating the wet plate, I think I was successful in my collodion pour, I let it spread across the whole plate, poured off the excess, and then let it dry for about 30 seconds. Then I put it in my silver bath (8g silver nitrate/100mL water) for four minutes. After this, I made the exposure, then came back to process it. I put it in developer (1:3 developer:water) for 15 seconds, then put it in fixer (1:4 fixer:water) until the image appeared, which didn't happen for the second and third exposures. Is there a problem with my process? I used Bostick and Sullivan developer, collodion, and silver nitrate. I used Ilford Rapid Fixer and all the water was distilled. I am confused but hopeful, any help, advice, comments, or opinions would be much appreciated! I am determined to take a picture on a cardboard box, nothing will stop me (except my complete lack of money and soon time).

P.S., I don't know why the images are so small, hopefully they're visible enough.

You seem to start from scratch with very little basic theory of photography ingested. You should at least research, how a camera of such design works.

How do you assure, you are in focus? You would need a moveable focus screen (ground glass), which I do not see on that box. I´d guess, your plate is too close to the (200-300mm?) lens, focussing to nowhere beyond infinity, resulting in a totally blurred "image". Cameras focus to infinity, when the sensor (here focus screen and wet plate) is placed at the noted focal length of the lens; to focus on closer things, the sensor needs to be pulled away from the lens. This is a matter of fractions of a mm, you cannot just place a sensor at a random distance to the lens and expect an image.

Not sure about the varieties of collodion, one can order at B&S, but maybe you just have wrongly ordered plain USP collodion (which would need to be mixed with certain chems to become light sensitive in combination with the silver nitrate) instead of ready to use collodion with the chems (iodides, bromides, alcohol and ether) already added at certain amounts. (Just a guess, why there is no reaction to light visible or even an image occuring).

Keep on!

[paulbarden]

You seem to start from scratch with very little basic theory of photography ingested. You should at least research, how a camera of such design works.

How do you assure, you are in focus? You would need a moveable focus screen (ground glass), which I do not see on that box. I´d guess, your plate is too close to the (200-300mm?) lens, focussing to nowhere beyond infinity, resulting in a totally blurred "image". Cameras focus to infinity, when the sensor (here focus screen and wet plate) is placed at the noted focal length of the lens; to focus on closer things, the sensor needs to be pulled away from the lens. This is a matter of fractions of a mm, you cannot just place a sensor at a random distance to the lens and expect an image.

Not sure about the varieties of collodion, one can order at B&S, but maybe you just have wrongly ordered plain USP collodion (which would need to be mixed with certain chems to become light sensitive in combination with the silver nitrate) instead of ready to use collodion with the chems (iodides, bromides, alcohol and ether) already added at certain amounts. (Just a guess, why there is no reaction to light visible or even an image occuring).

Keep on!

It appears to me that he is getting some reduced silver on the plates, probably unexposed silver developing out, so I don't think he is working with unsalted collodion. If he were, there would be no silver forming on those plates at all - they'd be black.

That said, I think your comment about focusing an image on the film plane is valid: I have no idea if that is being achieved or not.

Euli, is there any way you can find a local wet plate practitioner to spend an afternoon with you to properly demonstrate the process? You don't seem to be making any meaningful progress, and I think you will continue to struggle without some hands-on guidance.

I think your exposure times are still way too short to be registering an image. For example, this scene, using western daylight coming in a window, was a 2 and a half minute exposure using an f4.5 lens, wide open.

[ueli]

You seem to start from scratch with very little basic theory of photography ingested. You should at least research, how a camera of such design works.

How do you assure, you are in focus? You would need a moveable focus screen (ground glass), which I do not see on that box. I´d guess, your plate is too close to the (200-300mm?) lens, focussing to nowhere beyond infinity, resulting in a totally blurred "image". Cameras focus to infinity, when the sensor (here focus screen and wet plate) is placed at the noted focal length of the lens; to focus on closer things, the sensor needs to be pulled away from the lens. This is a matter of fractions of a mm, you cannot just place a sensor at a random distance to the lens and expect an image.

Not sure about the varieties of collodion, one can order at B&S, but maybe you just have wrongly ordered plain USP collodion (which would need to be mixed with certain chems to become light sensitive in combination with the silver nitrate) instead of ready to use collodion with the chems (iodides, bromides, alcohol and ether) already added at certain amounts. (Just a guess, why there is no reaction to light visible or even an image occuring).

Keep on!

It appears to me that he is getting some reduced silver on the plates, probably unexposed silver developing out, so I don't think he is working with unsalted collodion. If he were, there would be no silver forming on those plates at all - they'd be black.

That said, I think your comment about focusing an image on the film plane is valid: I have no idea if that is being achieved or not.

Euli, is there any way you can find a local wet plate practitioner to spend an afternoon with you to properly demonstrate the process? You don't seem to be making any meaningful progress, and I think you will continue to struggle without some hands-on guidance.

I think your exposure times are still way too short to be registering an image. For example, this scene, using western daylight coming in a window, was a 2 and a half minute exposure using an f4.5 lens, wide open.

I have been using B&S Workhorse Collodion, I think its all pre-mixed which is what I wanted. I did make a ground glass screen, I just couldn't figure out what it was supposed to be doing so I only used it once. I of course made a less than ideal version myself because it was cheaper. Is the ground glass supposed to go between the lens and the plate? Or is it supposed to go behind to show an image preview before the plate is inserted? Like you said, I'm just guessing at focal length so I can't be very sure of much that I'm doing. I am more aware than anyone how undesirable this is. I didn't know that the focal length could be used to determine how far to place the plate from the image though, that is helpful even if I can't actually use that information with much confidence.

I've looked up some local wet plate photographers, I may try reaching out to some if I can find a good time for it. School is starting soon (also the reason I have no money!) so I don't know if I will be able to spend much time on this project for awhile. I will continue to make adjustments and try different ideas based on what I learn about wet plate in the future, and I'll post anything interesting I get. Thanks for the help.

[paulbarden]

I have been using B&S Workhorse Collodion, I think its all pre-mixed which is what I wanted. I did make a ground glass screen, I just couldn't figure out what it was supposed to be doing so I only used it once. I of course made a less than ideal version myself because it was cheaper. Is the ground glass supposed to go between the lens and the plate? Or is it supposed to go behind to show an image preview before the plate is inserted? Like you said, I'm just guessing at focal length so I can't be very sure of much that I'm doing. I am more aware than anyone how undesirable this is. I didn't know that the focal length could be used to determine how far to place the plate from the image though, that is helpful even if I can't actually use that information with much confidence.

I've looked up some local wet plate photographers, I may try reaching out to some if I can find a good time for it. School is starting soon (also the reason I have no money!) so I don't know if I will be able to spend much time on this project for awhile. I will continue to make adjustments and try different ideas based on what I learn about wet plate in the future, and I'll post anything interesting I get. Thanks for the help.

You'll do yourself a favor by just buying an inexpensive box camera like a No. 3 Kodak Brownie Model B (see example wet plate photo here, made with that camera), which can be had for as little as $20 for a working example. This will take a lot of the guesswork out of what you're doing.

PS: the ground glass is supposed to be AT the image plane where the collodion plate is going to sit. Its purpose is to allow you to preview the image and get it correctly focused before putting the plate in the camera. But given how you've described your "camera" I'm not sure you can actually set focus correctly. Just get a "real" camera. Right now you're just wasting money and materials as you guess at how to make this work.