Plates coating trouble

[Herzeleid]

I hope a solution is found to this problem. I had those wavy lines on various plates. This particular plate has no chrome alum.


I pre-heat the glass over hot water, emulsion is sitting in hot bath of 40C constant. I carry some emulsion into a small beaker to coat exact amount.
I coat by hand wearing gloves (waiter method in collodion), I tilt the glass to coat it. Rarely I use a glass rod to push emulsion in order to fill the gaps.
These marks appear after drying.

I have tried Osterman's formula, Denise's modified AJ-12 formula and PAGI 3.2 from SPSE book. I use thymol, chrome alum (little or none) and ethanol in all my emulsions.
After looking at some plates I have noticed I have no lines on plates which I have used food grade gelatin (bloom 220-240).
They have no steigman solution, and they are not heated for long periods. They have no photo flo. Maybe it was a beginner's luck, later I turned to photo grade gelatin.

Regards
Serdar

 

[dwross]

Hi Serdar,

Thank you for the detail-rich post. It's a puzzle. I've been chewing on it (love puzzles). I haven't made plates in a couple of years since I settled on film and paper negatives for my own photography, but I'm feeling the urge to nail down the cause(s) of the swirlies. I'm making it my next project. Maybe all the plate makers here can do the same thing and we can compare notes. Have yours appeared in all the recipes you've made? What recipe did you use for the plate in your illustration? I hope you don't mind the questions! This forum seems like the perfect place for us to pool our work and observations. Time to end the conjecture and try to figure out the facts. d

 

[Nodda Duma]

Denise, that's a great idea. Here is the thread I started when I was having trouble early on.

https://www.photrio.com/forum/threads/emulsion-seems-to-react-with-nitrile-gloves.156966/

I did a lot of troubleshooting at the time which I documented in that thread. That included glass prep, cleaning methods, addition and non-addition of finals, coating method (syringe and glass rod, pour and tilt, etc), and coating with / without subbing layer. Silicone as used for lubrication of the syringe seemed to be a cause, but I can't say what the actual failure mode is .. i.e. what the silicone interacted with to change the sensitivity of the silver halide. In any case, I still saw the artifact with a fancy all-glass syringe (no silicone anywhere). The only believable correlation I found was scaling (4x) of the emulsion recipe... from 1L to 4L ...and the real change there was the time it took to heat/cool the emulsion batch due to the different thermal mass. Once I saw that I characterized the cooling / heating times for smaller batches and replicated the small batch temp times for a 2L batch. The swirlies completely went away, however recently I've seen the artifact come back occasionally on very thin developed plates. I haven't really found that I'm doing anything significantly different from what you, Mark, Ron, or others have been doing except my emulsion making equipment is a bit more advanced now for batch-to-batch repeatability .. it's similar to the level of control that Ron shows in his book. To summarize my recipe:

Iodine-bromide emulsion. 10 minute precip, 14 minute hold, chill to 40C over 30 minutes (mimics the smaller batch cooling times where I never saw the swirlies), dump the add gelatin, then set. Even my batch size is smaller than Jim Browning's matrix formula: https://www.photrio.com/forum/threads/making-a-dye-transfer-matrix-film.29949/
ACS grade silver nitrate from Chemsavers, LLC. Starting next batch I'll be using silver nitrate sourced from Kodak's supplier.
ACS grade KBr & KI
Photo grade Ossian gelatin, from B&S (I have somewhere in my notebook where they get theirs from)

The one thing I haven't really tested is correlation against the source of chemicals or the gelatin. It would be good to compare where we get our chemicals. After I tackle the silver nitrate I was going to look at potential correlations vs. gelatin by getting some from Photographer's Formulary which I believe they source from Kodak.

-Jason

 

[dwross]

Excellent. I'm very glad you'll be on our little adventure! I will carefully read the link you sent.

Gelatin is certainly at the top of my list of variables to look at. That's where I'm starting. I've got just about every photo gelatin there is, left over from writing a book on paper making. (Paper is SO easy compared to negative emulsions )

 

[Herzeleid]

Hi Denise,

This plate was done with Mark Osterman's formula, I was having problems with development so I removed chrome alum to test if it was a ripening or overhardening problem.
It appeared in all the formulas I have tried.
One exception which I used food grade gelatin it was the first emulsion I made so it was your modified AJ-12. So I refrained from overheating the emulsion with food grade gelatin.

I hope I will have time to try making new emulsion later, I was not able to do any emulsion during summer.

 

[Nodda Duma]

It'd be interesting to see if you can replicate it. The gelatin I use has been a constant since I started making plates for others. When I made plates solely for my own use, I bought from both photographer's formulary and B&S. It'll be interesting to hear what Serdar and Elvan Zao use for photo-grade gelatin.

 

[Herzeleid]

I have been using this gelatin
http://shop.silverprint.co.uk/Gelatin-250g-Inert-Photo-Quality/product/11187/11187/

 

[dwross]

Thanks Serdar. Very interesting. You say that my modification of AJ-12 worked with food grade gelatin, but not photo gelatin (is that correct?) Did you make the KBr or the Ammonium Br variation? I've never had swirlies with the AmBr recipe with Photographers' Formulary gelatin. However, I'm still using gelatin I stocked up on about three years ago. The gelatin they are selling now is different (finely granular, rather than coarse).

I have high confidence we'll get this figured out! We'll have to keep a running summary of data-to-date.

Jason, do you think you should ask for more input on your Facebook page (people who aren't buying your plates, of course!)?
d

 

[Nodda Duma]

It's been discussed in the Dry Plate Photographers FB group in the past, and I've asked Nick and Mark about it. They had never seen any issues either, and I presume they use Kodak's gelatin. These folks here are the only other people I've come across with this artifact, other than one old Ilford plate that had a similar artifact. Really I think this subforum here is the best place to solve the problem: Three different people having the same issue (with fresh eyes looking at the problem) is really helpful... it stands to reason that the root cause will be something our emulsion making has in common. I can make a table to track the similarities and differences between our three emulsions.

I was going to make a big batch with Photographer's Formulary gelatin and also do the same using Ammonia Bromide instead of KBr .. I want to change one variable at a time but using the same process that caused the problems with my emulsion to see what helps. I just haven't had time to do so.

 

[Herzeleid]

Hi Denise,

I am confident I never had problems with food grade gelatin. I tried the modified AJ-12 with photo grade, same swirlies. Sometimes they are not a big problem but sometimes they sit right in the center of the image.
I do not have ammonium salts, I never tried AmBr variations.
Silverprint's product is identical to formulary's product? Gelatin I have is quite coarse.

EDIT:

Although I did not have problems with food grade gelatin, my experience in emulsion making using food grade is quite little. I might have made 2-3 small batches. Some fogged and never used, some had other problems.

 

[Nodda Duma]

Silverprint's product is identical to formulary's product? Gelatin I have is quite coarse.

I looked and it doesn't specify the gelatin type on their page, so we don't know if it's the same or not. The chemical register numbers (CAS / EC) don't differentiate between gelatin types. We'd want to know the source (ossien vs pig) and the bloom, which Silverprint might be able to say if asked.

 

[Photo Engineer]

The Formulary was using Kodak gelatin from the plant in Peabody Mass. They ran through quite a bit and when they reordered, Kodak had sold the plant to Rousselot.

I have to assume it is the same or very similar. Mark and Nick use the same gelatin I do. I have checked, and I have one plate with this problem. It is a demo coated with a coating blade designed for plates. The plate was cleaned with Dichromate / Sulfuric acid and rinsed with DW.

PE

 

[Nodda Duma]

Ron, was your plate with that artifact an ammonia digest emulsion or made without ammonia?

 

[Photo Engineer]

I don' t remember OTOMH, but I have many others that were and were not both and there is no problem.

I do know that Mark and Nick use Dawn Detergent to wash the plates and have NEVER had a problem. I think it is a "prep" problem.

PE

 

[Herzeleid]

I wash the plates in dishwasher with hypochlorite, rinse with isopropyl before coating.

 

[Nodda Duma]

Either sonic bath with alcojet, followed by water rinse, or hand wash with dawn dish soap. Saw it with both methods when I was trying to determine the cause.

 

[dwross]

It's going to be very interesting to see what the cause is. It's not impossible that there is more than one way to "achieve" swirlies, and the problem might not be with the emulsion. I agree with Ron that cleaning could be a cause. Processing is a possible cause. An insufficiently mixed developer could do this. Uneven agitation in the developer is another. It might be an issue with the glass. Float glass might have minute imperfections on the surface that could pool teeny, tiny rivers of emulsion.

Question: What's everyone's opinion on how to best organize our data and observations? d

 

[Nodda Duma]

Denise I was going to generate a table to cross-reference between all the aspects of emulsion coating and our individual methods. That will highlight differences and similarities to help troubleshoot. This borrows from engineering failure analysis methods and is useful for methodically tracking down root causes. Since there isn’t an obvious root cause (I’ve been working on cracking this nut for months) I think the problem requires this approach

 

[dwross]

Excellent. Thank you.

 

[removed account4]

i scrub plates with a plastic bristle brush and washing soda and just rinse well with tap water haven't had a problem in years.
( with hand made and mostly store bought LSE)

 

[peter k.]

A bit off topic:
Love shooting Dry Plate, in two speed Graphics, by having modified a 4x5 and a 3x4 Graphic film pack adapter. Also use a 1930's 9 x12 folder, that has a slow shutter and needs a CLA, but which does not effect the exposure when shooting in seconds. Those film holders take both reg film or plates. But that's the full depth of my experience as a newbie. So could you explain:.

( with hand made and mostly store bought LSE)

Thanks... p.

 

[Photo Engineer]

Denise, Jason, I have seen the swirlies on unprocessed plates. In fact, my one example is an unprocessed demo plate.

PE

 

[removed account4]

Thanks... p.

yeah i did home made years ago and then seeing
i wasn't able to get help ( and i was a broke college student 30+ years ago )
i opted for store bought until recently when i started making from scratch again ..
people doing this are way better off now seeing there was no internet &c back then ..

 

[dwross]

I'm out of 4x5 plates and I won't have time to make any until after Christmas. I will wash them like I did after I stopped having any problems with my plates: paste of dye-free/perfume-free dish detergent (Seventh Generation) and whiting powder (calcium carbonate), applied with soft nail brush all over both sides of a plate. Very thorough tap water rinse, followed by a dip in distilled water and Everclear, 1:1, and air-dried in a dish rack.

My first set of tests will be with my AmBr recipe, using a different gelatin with each batch. Within a given batch, I'll use different developers. If I can figure out the logistics, I think I'll try to coat each batch in a couple of different ways.
fingers crossed, d

 

[Nodda Duma]

Denise, the plates I sent you long ago probably have that artifact, so you can see what they look like.