Wet Plate Collodion questions answered here.

[AgNO3]

Hey Alex,
I once got the recommendation to add more alcohol to the developer, to make it flow more even and won´t be repelled by the film. My professional wet plate chem dealer also adds some of this surface tension breaker, used with paper foto prints for an even development and drying of the paper.
All the best

[AlexGard]

Weird because it's the same amount of alcohol I've always used per volume, I just am puzzled as to how a higher alcohol to acid ratio would make it behave that way. Never had this issue with coffers recipe.

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[paulbarden]

I've not had these problems so consistently since I first started.

I've shot about 15 of these 5x7 clear glass plates and everyone single one of them the developer refuses to evenly cover the whole plate. I never usually suffer thus issue especially so consistently. This is the first time shooting the smaller format which you'd think make it easier

The two variables that have changed

-smaller format, new glass
-developer recipe

Where my old recipe was Coffer's (20g iron, 6mL alcohol, 6mL acid, 100mL water, 1g potassium nitrate 16 sec) i recently changed to

10g iron, 6mL alcohol, 3.6mL acid, 100mL water, 30 sec

But i wouldn't think the reduced acid would effect the flow so much, am I wrong? No matter how slow, fast, calm, quick, or how much I rock or aggressively agitate the plate i can see the developer repelling away from the dark spots on the plate. I'm going to go back to my original recipe, but why does this happen?

The first time I used this new formula I was shooting much larger plates and had no issues in fact it seemed to work perfectly. The only difference between now and then was it was a hot day and the last couple of times I've shot and failed its been colder.


The collodion (mavidon) was mixed fresh last night, as was the developer with the same batches of ingredients for each. I assume the acid to alcohol ratio has something to do with the dev not coating the whole plate evenly. No matter how hard i shake or how carefully i pour it just refuses to coat that area, it almost appears like there's oil or grease on that part of the plate the way the developer behaves and repels away from those areas.
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The fix is to add more alcohol to the developer. There are so many variables that can (and often do!) affect how collodion behaves. But it’s pretty clear from your description that what’s needed is more alcohol in your developer.

[AgNO3]

Weird because it's the same amount of alcohol I've always used per volume, I just am puzzled as to how a higher alcohol to acid ratio would make it behave that way. Never had this issue with coffers recipe.

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I´ve made different experiences with the same batch of dev; once ruined the first shot with oily dev but on the 2nd plate with the same dev, it went smooth. I think Paul gave me the tip, to pour the dev into the shot glass just before use, since the alcohol might evaporate while sitting for a while in the open shot glass. But its winter at yours, so heat evaporation shouldn´t be an issue right now.
Since the alcohol doesn´t do any harm to the dev process, I´m mixing a good 10%ish solution, so to 400ml h2o I add at least 40ml of 99%alcohol (cheap stove fuel/bio ethanol) just to be sure.

[AlexGard]

The fix is to add more alcohol to the developer. There are so many variables that can (and often do!) affect how collodion behaves. But it’s pretty clear from your description that what’s needed is more alcohol in your developer.

That was the most obvious thing to me as well. But as I said it's the same amount of alcohol I've always used and I've never had this problem before.

What would you start with? Add 10mL alcohol more to every 100mL dev?

Oh well.. I'll try again next wk with old recipe.

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[paulbarden]

That was the most obvious thing to me as well. But as I said it's the same amount of alcohol I've always used and I've never had this problem before.

What would you start with? Add 10mL alcohol more to every 100mL dev?

Oh well.. I'll try again next wk with old recipe.

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There have been days when I could not get a usable plate no matter what I tried, even using materials that worked perfectly the day before. Sometimes collodion is truly a baffling process. On days like that, I quit and try again another day.

[AlexGard]

There have been days when I could not get a usable plate no matter what I tried, even using materials that worked perfectly the day before. Sometimes collodion is truly a baffling process. On days like that, I quit and try again another day.

I had this same problem last week. I hadn't been able to shoot for a while due to car problems. I then drove 2 hours into the middle of nowhere to shoot some trees and couldn't get a plate. This week I thought id keep closer to home and see if fresh chemicals sorted the problem. Nope. Frustrating when I only get a small window

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[wetplatefinland]

Hello everyone. I am new to this forum but have shot wet plate for the past three years with normally quite succesfull results.

But now I have found an issue in my collodion. The collodion emulsion is partly peeling off while in the silver bath. This is sometimes coupled with the plate edges also drying up already.

What can cause this peeling? Is my collodion too wet or the nitrocellulose too weak? I mix my own chemicals and my raw collodion bottle of ÖAB ~4% is about 3 years old.

I have poured normal good plates in the past, but am I still making some error before I put the plate into the silver bath?

I feel like I have two problems at the same time: too wet collodion in plate center + too dry collodion at plate edges.

Below are two photos: one showing the peeling, and one showing peeling in the bottom + drying at the edges.

Please help! Thanks!

[paulbarden]

Hello everyone. I am new to this forum but have shot wet plate for the past three years with normally quite succesfull results.

But now I have found an issue in my collodion. The collodion emulsion is partly peeling off while in the silver bath. This is sometimes coupled with the plate edges also drying up already.

What can cause this peeling? Is my collodion too wet or the nitrocellulose too weak? I mix my own chemicals and my raw collodion bottle of ÖAB ~4% is about 3 years old.

I have poured normal good plates in the past, but am I still making some error before I put the plate into the silver bath?

I feel like I have two problems at the same time: too wet collodion in plate center + too dry collodion at plate edges.

Below are two photos: one showing the peeling, and one showing peeling in the bottom + drying at the edges.

Please help! Thanks!

The most likely culprit is - as you've suspected - is the collodion. Collodion doesn't age well, especially if stored in a place where it gets warm for periods of time. As yours is now 3 years old, and your collodion seems to be misbehaving, that is the first things I would suggest changing: buy fresh and start over.

I assume you are maintaining your silver bath as prescribed, yes? If collodion is coming off in the silver bath, it must be filtered out!

[wetplatefinland]

The most likely culprit is - as you've suspected - is the collodion. Collodion doesn't age well, especially if stored in a place where it gets warm for periods of time. As yours is now 3 years old, and your collodion seems to be misbehaving, that is the first things I would suggest changing: buy fresh and start over.

I assume you are maintaining your silver bath as prescribed, yes? If collodion is coming off in the silver bath, it must be filtered out!

Thanks for your quick reply.

I regularly filter and maintain my silver bath. It is always kept clean of detached collodion emulsion.

Just to clarify one thing: my mixed collodion is also always fresh... but... the raw collodion is suspectedly expired.