Plates coating trouble

dwross · Nov 16, 2018

I'm afraid I know all too well what they look like. I've "made" my own. Much worse than yours (as if it's a competition! ) I'm annoyed that I can't find one of those plates. I generally keep samples of all problems. But, I've gotten pretty ruthless with the de-cluttering. Only so much junk any one studio can hold!

I loved the plates you sent. They were from your very early batches and I think they are lovely. The "imperfections" don't bother me a bit. I don't think of them as "swirlies," however. (I will broaden my definition of what we're investigating.) I turned your plates into digital negatives to contact print on gaslight and POP paper. Didn't take much work at all to make a good digital negative.

dwross · Nov 16, 2018

Following the idea of broadening definitions and puzzles -- here's one. I hadn't put it together with swirlies until now, but it might be related somehow. I've got the whole thing blogged on TLF, but here's the short form: One single 120 (actually, 620) roll of AmBr emulsion, sensitizied to be panochromatic. Exposed in a Brownie Hawkeye with blue, green, and red filters. Processed all at the same time. Tri-color assemblage.

Only the frames exposed through the red filter showed artifacts. This suggests that the entire roll actually had them, but they only presented when exposed through red light. I have no idea what this may or may not mean, but it might be a data point, or hypothesis launch point.

Photo Engineer · Nov 16, 2018

Denise, I can't see the imperfections very well in the tricolor example. It just does not show up to the extent I would imagine, especially being the cyan dye record. This is quite odd.

Also, the frequency of the light/dark pattern is not quite as short as in the examples I have seen before.

Could this be something different?

dwross · Nov 16, 2018

Thank you! Ron! Good catch. Yes, I didn't include the uncorrected image. Will do so now. And, while I'm at it, might as well find and post the blog entry.

http://www.thelightfarm.com/cgi-bin/htmlgendiary.py?content=Journal3 (second panel from top: October 14, 2016). Now that's a shock. Time went down the rabbit hole while I've been writing a book. Glad to be back researching film. I'm very excited that a number of us will be bumping our heads together on the swirlies issue. d

Photo Engineer · Nov 16, 2018

That still does not look as severe as in the separation image. And, now it reminds me of flare. That is very odd to me. Something different may be involved here. Have you considered that? As I noted above, I have seen it on a dry unprocessed plate.

Elven Zao · Nov 16, 2018

Finally I found the chief criminal !! Silicone oil in syringe!

dwross · Nov 16, 2018

Photo Engineer said:
...

Also, the frequency of the light/dark pattern is not quite as short as in the examples I have seen before.

Could this be something different?

The scans of the film are straight off the scanner. Nothing done to them except re-size to jpeg. They are what they are. The patterns in the red frames were essentially the same across the whole roll, so it's not a localized problem.

Do you have an example of the light/dark pattern you're thinking of? What is the cause of those? What I got probably is different. Modern panchromatic film is made very differently from how I do it!

dwross · Nov 16, 2018

Elven Zao said:
Finally I found the chief criminal !! Silicone oil in syringe!

YAY! Congratulations!

Good luck going forward. I hope you continue to contribute to this investigation. I've never used a syringe to coat plates and I got swirlies in my early plates. d

Elven Zao · Nov 16, 2018

Elven Zao said:
Finally I found the chief criminal !! Silicone oil in syringe!

It's a new syring, when I open it from a sealed bag，I found it , it destroyed 1000ml emulsion of mine

Elven Zao · Nov 16, 2018

dwross said:
YAY! Congratulations!

Good luck going forward. I hope you continue to contribute to this investigation. I've never used a syringe to coat plates and I got swirlies in my early plates. d

Thank you , I'll continue to contribute to this investigation.

Nodda Duma · Nov 16, 2018

I had found that as well was causing swirlies as described in my other thread, but long after switching to an all-glass syringe I still saw the artifact.

However... Another source of silicone could be latex or nitrile gloves that have residual silicone from the mold release.

Photo Engineer · Nov 16, 2018

dwross said:
The scans of the film are straight off the scanner. Nothing done to them except re-size to jpeg. They are what they are. The patterns in the red frames were essentially the same across the whole roll, so it's not a localized problem.

Do you have an example of the light/dark pattern you're thinking of? What is the cause of those? What I got probably is different. Modern panchromatic film is made very differently from how I do it!

I'm still thinking about this Denise.

As for the syringes, I think that Mark and Nick never use them. I use them only when coating with blades. When I do use them, I use veterinary syringes that are supposed to be free of silicone oils.

PE

Herzeleid · Nov 18, 2018

I use insulin syringes and other medical syringes it is unlikely they have any oils in them. I also clean them seperate the body and the push stick dry and re use. Never saw any oily residue.

I will check the cleaning procedure as Ron suggests, I will coat ordinary glass with gelatin and some with gelatin and pigment. The reason is I have seen similar swirl patterns appear on some carbon tissues after drying. I didn't paid much attention since I am still testing pigments and other things.They do not appear on final image but the content of glop is similar enough gelatin and ethanol wise. Since all the swirly dry plates work as expected I consider that not to be a problem of sensitizing dyes, silver halides or alum.

dwross · Nov 18, 2018

I agree that the ingredients themselves are probably not the problem (unless it's how evenly the finals are incorporated). Could the glass itself have anything to do with swirlies? Uneven patches of density are probably something different. I'm going to try to test if the side of a sheet of glass we coat on makes a difference. https://en.wikipedia.org/wiki/Float_glass

Nodda Duma · Nov 18, 2018

If it were the glass, swirlies would have been seen in old plates more often. Soda lime was the choice then (the only choice) as it is now.

dwross · Nov 18, 2018

Jason, I don't disagree. It's a stretch. Nothing points to it being the problem, except...it's the only commonality I can identify so far. Chasing down the contrapositive to "settled" facts has taken me a long way in my emulsion research .

Photo Engineer · Nov 18, 2018

The fact remains that they have never seen it at GEM AFAIK. And they make a lot of plates.

I believe that no one has seen it on film, and that does indicate that it is something related to plate coating.

PE

Herzeleid · Nov 21, 2018

Greetings everyone,

I think it might be related to heat, both the pouring temperature of the gelatin emulsion and temperature the glass. It might even be related to how fast it is cooling.
I lay my glasses over hot water to heat them, coat them then I lay them on marble after pouring is done. Difference in heat during setting or just the high temperature itself might be the culprit.

I did a test with carbon tissues since I don't have a dry plate emulsion at the moment. Gelatin mixture at poured at 50C show incredible swirly lines. They also appear on the print.
Pouring gelatin at 40C show no lines when it dries. Room temperature was 22C.

Similar problem in carbon printing.
https://groups.io/g/carbon/message/6642

Sorry I don't have more photos to show, forgive the lousy print. But these are the lines appear on my plates, I somewhat reproduced a similar problem.

In an earlier post, I mentioned I never had the problem with food grade gelatin. I never past 40C with food grade gelatin. This makes sense why I haven't seen those lines.

I hope someone can repeat it with silver gelatin emulsion to confirm or bust it.

Regards
Serdar

Nodda Duma · Nov 21, 2018

My emulsion is held in a water bath at 40C during my coating session. Plates are held at 30C until they are placed on a 20C plate for coating, then set up at 20C. Ambient is held at 20C. I control these temperatures for batch-to-batch consistency.

I suspect that the time at temperature is important, since the gelatin begins to dissociate after some period of time. My thought is as this occurs there are pockets of gelatin that can no longer protect the silver grains from growing or clumping. So lower temperatures allow for longer working time. This includes time at elevated temps during ripening and why my swirlies pretty much went away when I reduced temperature ramping times for larger batches.

I also suspect ammonia digest emulsions don’t necessarily have this issue because the emulsion doesnt see as high a temperature.

That’s my theory. Silicone, I think, causes the gelatin to dissociate faster.

dwross · Nov 21, 2018

Hi Serdar,
That is very good news and information. Thank you. Tracks right in line with the way I settled on making my best plates. I will try to make an emulsion recipe asap, and hopefully, so will everyone else! One of the things that's most satisfying about making emulsions is that is seems the "best" way to make just about any recipe turns out also to be the easiest way. , d

Herzeleid · Nov 21, 2018

Nodda Duma said:
My emulsion is held in a water bath at 40C during my coating session. Plates are held at 30C until they are placed on a 20C plate for coating, then set up at 20C. Ambient is held at 20C. I control these temperatures for batch-to-batch consistency.

I suspect that the time at temperature is important, since the gelatin begins to dissociate after some period of time. My thought is as this occurs there are pockets of gelatin that can no longer protect the silver grains from growing or clumping. So lower temperatures allow for longer working time. This includes time at elevated temps during ripening and why my swirlies pretty much went away when I reduced temperature ramping times for larger batches.

I also suspect ammonia digest emulsions don’t necessarily have this issue because the emulsion doesnt see as high a temperature.

That’s my theory. Silicone, I think, causes the gelatin to dissociate faster.

Jason

How do you keep plates at 30C? I just put them on a stand over hot water, I have no control over the temperature of the plates, they are just warm enough for me to spread the emulsion.
Do you lay them on a stone afterwards?
Time and temperature during ripening is another variable certainly. So longer ripening at lower temperatures might help. I will keep that in mind for the next batch.

Herzeleid · Nov 21, 2018

dwross said:
Hi Serdar,
That is very good news and information. Thank you. Tracks right in line with the way I settled on making my best plates. I will try to make an emulsion recipe asap, and hopefully, so will everyone else! One of the things that's most satisfying about making emulsions is that is seems the "best" way to make just about any recipe turns out also to be the easiest way. , d

Hi Denise,

I hope it is the right track, controlling temperature appears to be even more crucial. Emulsion making gets more trickier. But I agree the best way appears to be what comes the easiest for an individual
I will try to do a simpler emulsion next time, no need to be too ambitious.

Nodda Duma · Nov 21, 2018

Herzeleid said:
Jason

How do you keep plates at 30C? I just put them on a stand over hot water, I have no control over the temperature of the plates, they are just warm enough for me to spread the emulsion.
Do you lay them on a stone afterwards?
Time and temperature during ripening is another variable certainly. So longer ripening at lower temperatures might help. I will keep that in mind for the next batch.

I have a large TEC plate that I warm them up on. The temp of the plate can be set.

Nodda Duma · Nov 29, 2018

I spoke to Nick at George Eastman Museum and he has in fact seen swirly artifscts in workshops. More importantly, he saw them where the emulsion has sat at temperature for extended periods of time, but not when he’s been able to work through the batch faster. He didn’t indicate time frames, so we don’t yet know how long is too long at what temperatures. That would require careful testing.

So I think this reinforces the correlation I was seeing between swirly artifacts and time at temperature.

Herzeleid · Nov 29, 2018

Great news, at least the problem can be narrowed to one parameter.

I recall reading cooking emulsion for hours and hours in olden days, how come they didn't have any weird problems or marks like these.

Plates coating trouble

dwross

Attachments

dwross

Attachments

Photo Engineer

dwross

Attachments

Photo Engineer

Elven Zao

Attachments

dwross

dwross

Elven Zao

Elven Zao

Nodda Duma

Photo Engineer

Herzeleid

dwross

Nodda Duma

dwross

Photo Engineer

Herzeleid

Nodda Duma

dwross

Herzeleid

Herzeleid

Nodda Duma

Nodda Duma

Herzeleid

Plates coating trouble

Attachments

Attachments

Attachments

Attachments

Privacy & Transparency

Privacy & Transparency