My PC-512 Borax Developer

albada said:

I just ran across another developer similar to PC-512 Borax, and added it to the table below. What's interesting is that this formula was published in 1968.

Chemical	PC-512 Borax	PG110B	Dignan Experimental
Borax	108	15	100
Ascorbic acid	12	5	100 (ascorbate)
Phenidone	0.5	0.5	2

.
I converted all quantities to a dilution of 1:50. The new formula by Dignan (rightmost column) has a pH of about 9.0.
This Dignan formula shows us that PC developers were known in the 1960's. I found it in "150 Popular B/W Formulas" from 1977, and it states that Dignan's formula appeared in Paul Farber's column in U.S. Camera in May, 1968.

Edit: The description of the developer in "150 Popular B/W Formulas" has this paragraph:

You may wonder why we have not used Ascorbic Acid instead of Sulfite. The reason is that Ascorbic Acid is easily destroyed by heat. Note the above temperatures [for making a percentage solution of Phenidone]. It is also destroyed by alkali.​

​

Edit 2: I had no problem with dissolving AA in glycol at 85 degrees C, and I've heard no reports of heat-related problems with AA, so I don't think heat is a problem. And we're using our formulas in alkaline solutions, which is not destroying the AA, so it appears that at the pH values we use, alkalinity is not a problem either. But we know to be careful about the Fenton reaction, which folks in 1968 might not have been aware of.

​

​

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Thanks for posting that, Mark. That is a lot of ascorbate! He seems to have been trying to replace sulfite with it 1:1. I found the original article and he was aware that it was superadditive with phenidone. But still looked at it mostly as a replacement for sufite. I wonder whether that much ascorbate does anything productive.

Regarding heat: yes there is no problem heating ascorbic acid up to 80-85C at all. This is what I used to dissolve it in glycol also.

aparat said:

I am really enjoying this thread, the information, and your photographs. It seems you've created a great developer. I might actually give it a try. I have all the ingredients. Thank you for sharing your knowledge!

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Thanks for the kind words! I much appreciate that. Yes, please have a play with the developer. Interested to see what you think if you do.

Andrew O'Neill said:

Karl, I hope you don't mind me sticking my video here! I played around with your developer, comparing it to Xtol.

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5 grams of phenidone? see 2:52 Is it possible that I have a mistake in the formula?



Is there a reason to use Phenidone instead of Dimezone?



thanks for sharing your findings

Castrillo said:

5 grams of phenidone? see 2:52 Is it possible that I have a mistake in the formula?



Is there a reason to use Phenidone instead of Dimezone?



thanks for sharing your findings

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It's 0.5g of Phenidone. I believe that is what I said.. and measured out

relistan said:

Thanks for posting that, Mark. That is a lot of ascorbate! He seems to have been trying to replace sulfite with it 1:1. I found the original article and he was aware that it was superadditive with phenidone. But still looked at it mostly as a replacement for sufite. I wonder whether that much ascorbate does anything productive.

Regarding heat: yes there is no problem heating ascorbic acid up to 80-85C at all. This is what I used to dissolve it in glycol also.

Thanks for the kind words! I much appreciate that. Yes, please have a play with the developer. Interested to see what you think if you do.

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I mixed up your PC-512 Borax Developer. I am waiting for it to cool overnight and may try some tests tomorrow, if I have time. Do you think rotary processing should be okay or should I use inversion agitation? Either is fine with me.

aparat said:

I mixed up your PC-512 Borax Developer. I am waiting for it to cool overnight and may try some tests tomorrow, if I have time. Do you think rotary processing should be okay or should I use inversion agitation? Either is fine with me.

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I did rotary with BTZS tubes in my video. It's fine. If you go to the 15:55 mark in the video, you can see an example with dmin/max, b+f, etc. I developed it in BTZS tube for 7 minutes. I used 1+50, and 1+100 dilutions...

Andrew O'Neill said:

I did rotary with BTZS tubes in my video. It's fine. If you go to the 15:55 mark in the video, you can see an example with dmin/max, b+f, etc. I developed it in BTZS tube for 7 minutes. I used 1+50, and 1+100 dilutions...

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Thank you. I should have read this thread more thoroughly. I will try the same dilutions, most likely with Delta 100 and Tri-X 400.

aparat said:

Thank you. I should have read this thread more thoroughly. I will try the same dilutions, most likely with Delta 100 and Tri-X 400.

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Looking forward to seeing your results, especially with Tri-X!

aparat said:

Thank you. I should have read this thread more thoroughly. I will try the same dilutions, most likely with Delta 100 and Tri-X 400.

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The grain I think is likely to be worse with constant agitation and higher dilution. I am guessing these may be partly why Andy didn’t get results like mine. I recommend 1+50 and inversion once a minute. But you of course should feel free to try any experiments!

relistan said:

Thanks for posting that, Mark. That is a lot of ascorbate! He seems to have been trying to replace sulfite with it 1:1. I found the original article and he was aware that it was superadditive with phenidone. But still looked at it mostly as a replacement for sufite. I wonder whether that much ascorbate does anything productive.

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Where did you find the original article? In a library?
Regarding ascorbate and phenidone, the author might have been thinking of parallels with sulfite and metol.


However, ascorbate is not a halide solvent, and without that, EI (speed) will probably be lower and grain will be worse.
It would be interesting to add small amounts of thiocyanate or sodium chloride or DTOD to PC-512 Borax and watch what happens to speed/sharpness/grain.

Mark

I tested it with CatLABS 80 II, not Delta 100. The grain between the two films are so different. I also did tray development in the video...Semi-stand. The difference in grain was subtle between continuous and Semi-stand. I like the developer more when a wee bit of Benzo was added. Overall, PC-512 is a very good developer. I still need to try it with other films...

I just finished my preliminary test of the PC-512 Borax film developer. I processed Ilford Delta 100 (exposed at EI 100) and Kodak Tri-X 400 (exposed at EI 400). To make any kind of conclusion, I would have to do a lot more testing. I plan to do that. I have run out of film, so it'll have to wait, but I hope to finish testing in a few weeks. Sorry about that!

My impressions are very positive. The developer is very easy to mix and seems economical. The only potential issue is the price and availability of borax in different parts of the world. Mixing was very easy. It took me about ten minutes to dissolve the ascorbic acid and Phenidone in glycol, reheating in my microwave a couple of times.

I diluted it 1+49, processed in a Jobo 1510 tank with 250 ml of total solution volume. I developed for seven minutes. I used inversion agitation, continuous for the first thirty seconds and then five seconds every minute, at 20C. I used an indicator stop bath and Clayton Rapid Fixer, followed by a quick rinse in water and one minute in Kodak Hypo Clearing Agent. I dried the samples in my film cabinet and read the densities into my program. Here are the results.

Ilford Delta 100
The developer produced full box speed, a typical near-linear Delta curve, and a CI of 0.64. In other words, a perfect result. Accounting for average lens flare, this would be a great "normal" development time. Graininess is exceptionally smooth and fine. The B+F density was 0.34, which is about average.

delta100_pc512borax by Nick Mazur, on Flickr

delta100_pc512boraxDetail by Nick Mazur, on Flickr

delta100PC512Borax by Nick Mazur, on Flickr

Kodak Tri-X 400
The developer produced the estimated speed of ISO 160. However, this is a predicted value based on a hypothetical curve with the G=0.62. It's quite possible that, had I developed for, say, eight minutes, the film might have reached ISO 200, which is typical for this film. So please, do not put too much stock into the ISO 160 value per se. The curve was also near-linear, with the CI of 0.53. Personally, I would have preferred another minute or so in the developer, but this might work for a lot of people, especially with a hybrid workflow where lower contrast can be a good thing. Grain is, understandably, more coarse than Delta 100, but it is still very fine and sharp. The B+F density was 0.27, which is about average.

trix400_pc512borax by Nick Mazur, on Flickr

trix400_pc512boraxDetail by Nick Mazur, on Flickr

400TX_PC512Borax by Nick Mazur, on Flickr

It's been a pleasure working with this developer and participating in this thread. My congratulations to @relistan !

@aparat , can you compare these results (curves and photos) with Xtol or D-76?

Andrew O'Neill said:

It's 0.5g of Phenidone. I believe that is what I said.. and measured out

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I will have to keep insisting, in addition to what you say there is a picture and what you see in the picture is not half a gram of Phenidone, it is much more.

0.5 grs is half of 1 gr.

albada said:

Where did you find the original article? In a library?

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It looks like it's slightly later than the one you had, but same formula. I found it here after you posted and I went looking: https://www.filmkorn.org/150-dyi-black-and-white-formulas-dignan/?lang=en

albada said:

Regarding ascorbate and phenidone, the author might have been thinking of parallels with sulfite and metol.

Sulfite regenerates metol. Ascorbate regenerates phenidone.​

Sulfite preserves metol. Ascorbate preserves phenidone.​

However, ascorbate is not a halide solvent, and without that, EI (speed) will probably be lower and grain will be worse.

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As you know from other discussions, I am not sure if it will or not. I have started to doubt the old adages about solvency and speed, and solvency and grain. There is definitely an opportunity for improvement by using solvents.

albada said:

It would be interesting to add small amounts of thiocyanate or sodium chloride or DTOD to PC-512 Borax and watch what happens to speed/sharpness/grain.

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I very much agree and am waiting for a shipment from Suvatlar that has both potassium thiocyanate and ammonium thiocyanate. I am not sure why it has been three weeks and not arrived yet...

Andrew O'Neill said:

I tested it with CatLABS 80 II, not Delta 100. The grain between the two films are so different. I also did tray development in the video...Semi-stand. The difference in grain was subtle between continuous and Semi-stand. I like the developer more when a wee bit of Benzo was added. Overall, PC-512 is a very good developer. I still need to try it with other films...

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Sorry Andy, I wasn't saying you did anything wrong. I was just cautioning that if Nick was going to test it, he should also make sure to test it the way I have used it. I appreciate you testing out semi-stand and 1+100 and with benzo added as well. It's all helpful to all of us in making progress!

aparat said:

I just finished my preliminary test of the PC-512 Borax film developer. I processed Ilford Delta 100 (exposed at EI 100) and Kodak Tri-X 400 (exposed at EI 400). To make any kind of conclusion, I would have to do a lot more testing. I plan to do that. I have run out of film, so it'll have to wait, but I hope to finish testing in a few weeks. Sorry about that!

My impressions are very positive. The developer is very easy to mix and seems economical. The only potential issue is the price and availability of borax in different parts of the world. Mixing was very easy. It took me about ten minutes to dissolve the ascorbic acid and Phenidone in glycol, reheating in my microwave a couple of times.

I diluted it 1+49, processed in a Jobo 1510 tank with 250 ml of total solution volume. I developed for seven minutes. I used inversion agitation, continuous for the first thirty seconds and then five seconds every minute, at 20C. I used an indicator stop bath and Clayton Rapid Fixer, followed by a quick rinse in water and one minute in Kodak Hypo Clearing Agent. I dried the samples in my film cabinet and read the densities into my program. Here are the results.

Ilford Delta 100
The developer produced full box speed, a typical near-linear Delta curve, and a CI of 0.64. In other words, a perfect result. Accounting for average lens flare, this would be a great "normal" development time. Graininess is exceptionally smooth and fine. The B+F density was 0.34, which is about average.

delta100_pc512borax by Nick Mazur, on Flickr

delta100_pc512boraxDetail by Nick Mazur, on Flickr

delta100PC512Borax by Nick Mazur, on Flickr

Kodak Tri-X 400
The developer produced the estimated speed of ISO 160. However, this is a predicted value based on a hypothetical curve with the G=0.62. It's quite possible that, had I developed for, say, eight minutes, the film might have reached ISO 200, which is typical for this film. So please, do not put too much stock into the ISO 160 value per se. The curve was also near-linear, with the CI of 0.53. Personally, I would have preferred another minute or so in the developer, but this might work for a lot of people, especially with a hybrid workflow where lower contrast can be a good thing. Grain is, understandably, more coarse than Delta 100, but it is still very fine and sharp. The B+F density was 0.27, which is about average.

trix400_pc512borax by Nick Mazur, on Flickr

trix400_pc512boraxDetail by Nick Mazur, on Flickr

400TX_PC512Borax by Nick Mazur, on Flickr

It's been a pleasure working with this developer and participating in this thread. My congratulations to @relistan !

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@aparat, thank you! I really, really appreciate you testing this out so thoroughly! Very good to have your work to compare against all the other configurations of film/developer you have tested. Much appreciated.

The Delta 100 result has me very pleased as this is the film I worked with in formulating this developer. That is a very interesting result with Tri-X. This makes me think I somewhat under-developed the two rolls that I did. They were expired and the density was harder to gauge because there was a little fog. When I get a chance I will try running 8 minutes on a fresh roll and see how it goes. In the meantime I will update my blog post to point to you results here for both films, if you don't mind.

albada said:

@aparat , can you compare these results (curves and photos) with Xtol or D-76?

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Mark, he has a lot of stuff on his Flickr feed, including Delta 100 grain photos with HC-110 and Thornton's Two Bath. He has H&D curves of

Delta 100 in XTOL: (Nick Mazur on Flickr)

Delta 100 in D-76: (Nick Mazur on Flickr)

Castrillo said:

I will have to keep insisting, in addition to what you say there is a picture and what you see in the picture is not half a gram of Phenidone, it is much more.

0.5 grs is half of 1 gr.


View attachment 329906

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And I will have to keep insisting that what I measured out was HALF a gram... 0.5. I was there. I measured it out
You should see how much Phenidone there is in one gram when I make 500ml stock solution A, Pyrocat-HD

Castrillo said:

Is there a reason to use Phenidone instead of Dimezone?

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Phenidone is cheaper and is what I have. Photogrpahically they should be equivalent. Dimezone's main advantage AFAIK is better life in aqueous solution, but it doesn't apply to this developer because it's only in aqueous solution one-shot. If you substitute Dimezone mol for mol I think you will get the same results.

Here's another, recent under-the-bridge shot.

Pentacon Six TL with Carl Zeiss Jena Flektogon 4/50mm on Kentmere PAN 400 at box speed. PC-512 Borax 1+50 for 8m40s at 20C.

relistan said:

Here's another, recent under-the-bridge shot.

Pentacon Six TL with Carl Zeiss Jena Flektogon 4/50mm on Kentmere PAN 400 at box speed. PC-512 Borax 1+50 for 8m40s at 20C.

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It's beautiful. There's subtlety to light and shadow here that's just outstanding.

aparat said:

It's beautiful. There's subtlety to light and shadow here that's just outstanding.

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Thanks a lot!

...and at box speed too. That alone is pretty impressive.

relistan said:

Phenidone is cheaper and is what I have. Photogrpahically they should be equivalent. Dimezone's main advantage AFAIK is better life in aqueous solution, but it doesn't apply to this developer because it's only in aqueous solution one-shot. If you substitute Dimezone mol for mol I think you will get the same results.

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Phenidone is quite a light powder, so 0.5g does look like a lot. My Dimezone-S is in granules, so it's far less bulky.

I have mixed Pyrocat-HDC with both phenidone and Dimezone-S and have found results to be indistinguishable. I used equi-molar amount of Dimezone-S plus 10% because I had read years ago that that was necessary.

Andrew O'Neill said:

...and at box speed too. That alone is pretty impressive.

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I suspect the reason PC-512 Borax reaches box speed is the ascorbic/phenidone ratio is 24, which is around half of the common ratio of >=40. Patrick Gainer ran tests on ascorbate developers long ago, and found that development-rate has little increase above a ratio of 40x, which is probably why most developers use high ratios. Another reason for a high ratio is improved longevity: If some ascorbate is oxidized, it's more likely that enough will remain to develop at about the normal rate.

Dr. Blood did the opposite when he created the following speed-enhancing developer. Here is the formula for one liter of working solution:

Sodium Metaborate (Kodalk)	8.75 g
Ascorbic Acid	1 g
Phenidone	0.1 g

.
A posting about this developer is here. It's in this thread.
He claims a film-speed increase of 100-150 percent! I'm skeptical, but it's likely to increase film-speed because the ratio is only 10, causing a higher fraction of phenidone to be exhausted in dense areas compared to shadow areas, causing shadows to develop more. The ratio of PC-512 Borax is 24, so I wouldn't be surprised to see a small film-speed increase, or at least no loss of speed.

Mark

aparat said:

It's beautiful. There's subtlety to light and shadow here that's just outstanding.

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That’s true, and all credit to Karl for that. But - without wishing to detract anything from Karl’s successful formulation - can we honestly say it’s due to the developer?
The curves you posted above are not substantially different from the same film in some other developers. Are we in the realm of subtle aesthetic effects that cannot be measured? And if so, are they real?

snusmumriken said:

That’s true, and all credit to Karl for that. But - without wishing to detract anything from Karl’s successful formulation - can we honestly say it’s due to the developer?
The curves you posted above are not substantially different from the same film in some other developers. Are we in the realm of subtle aesthetic effects that cannot be measured? And if so, are they real?

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I believe you are right. Once the overall sensitometric performance has been evaluated, we still have a few quantitative tools left. We could measure the film's spectral response (unlikely to vary by developer), Modulation Transfer Function, adjacency effects, graininess, etc. Lacking those, we are left with qualitative descriptions, such as those in this thread.

If I were to use words to describe the differences between Delta 100 and 400TX in the PC-512 Borax developer, I'd say that Delta 100 looks "creamy" in the sense of George E. Todd (Elements of Black and White Photography, Amphoto Books, 2001) and 400TX looks "sharp" in the sense of Barry Thornton (Edge of Darkness, Amphoto Books, 2001), but such words are much harder to interpret due to their subjectivity.

What I look for in my tests of the developer is curve shape, with the degree of shadow, mid-tone, and highlight linearity, film speed, B+F density, etc. Most conventional developers (D-76, XTOL, ID-11, etc.) are going to give somewhat similar performance in that regard, but may vary with regard to agitation, temperature, duration.

I don't know if I would call PC-512 Borax a conventional developer, but it does not have anything exotic or idiosyncratic in it, so we would expect good performance, overall. There are all these adages and stereotypical descriptions of developers floating around, but @relistan decided to chuck many of them and go ahead with his design. Of course, it's very difficult to formulate such a solid all-around developer, and I feel I need to congratulate @relistan on succeeding to do so. Further testing is required to see how this developer works with other films, other dilutions, agitation methods, etc.

albada said:

I suspect the reason PC-512 Borax reaches box speed is the ascorbic/phenidone ratio is 24, which is around half of the common ratio of >=40. Patrick Gainer ran tests on ascorbate developers long ago, and found that development-rate has little increase above a ratio of 40x, which is probably why most developers use high ratios. Another reason for a high ratio is improved longevity: If some ascorbate is oxidized, it's more likely that enough will remain to develop at about the normal rate.

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Gainer was interested in economy as well, and was trying to find a ratio that worked well and was sufficiently cheap. I wasn't concerned with economy at such low amounts of agents. I tried various ratios when working on the two bath developers from which PC-512 Borax evolved. I found that the ratio makes a difference in the density and image output, even accounting for time. I started with 40:1 and found images that I subjectively liked best around 24:1. I think this does play a part in reaching box speed: there is a lot of phenidone in comparison to some of the other dilute developers. But I also think that borax has something to do with it. I have been trying to figure out if that's true and what that might be. I certainly never got box speed with PC-Glycol and carbonate, despite the pH being much higher.

Normally reaching box speed (in theory) involves some solvent to expose buried latent image centers, but I was surprised to find with this developer that I could shoot at box speed and get great negatives without loss of shadow detail. @aparat has kindly done the work to confirm, with much better precision than I have, that this is correct.

Thinking through as much theory as I can, and lacking any proof that borates are special (though notice most of the successful ascorbic acid developers seem to have it?), the only other idea I have is that the low-ish pH may prevent any real gelatin swelling. I would think that swelling would prevent the gelatin from remaining adsorbed to the surface of the grain, but perhaps it's the opposite. Perhaps the swelling actually further blocks development from reaching all surfaces of the grain. If that's true (I need more reading) then it could perhaps partly explain reaching box speed with minimal swelling. This is also around the pH of XTOL.

albada said:

Dr. Blood did the opposite when he created the following speed-enhancing developer. Here is the formula for one liter of working solution:

He claims a film-speed increase of 100-150 percent! I'm skeptical, but it's likely to increase film-speed because the ratio is only 10, causing a higher fraction of phenidone to be exhausted in dense areas compared to shadow areas, causing shadows to develop more. The ratio of PC-512 Borax is 24, so I wouldn't be surprised to see a small film-speed increase, or at least no loss of speed.

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I'm skeptical of that claim as well. This is the same ratio as PG-110B, and a similar pH is likely as well. Given that 0.01g of phenidone with virtually *any* amount of ascorbic acid present will heartily develop film—though not nicely, for sure—I don't know if I can believe in exhaustion happening, either. I tested this out when trying to formulate a two bath with ascorbic acid. It's almost impossible to keep the second bath from becoming a good developer because the phenidone/ascorbic acid pair is so active in even tiny amounts.

snusmumriken said:

That’s true, and all credit to Karl for that. But - without wishing to detract anything from Karl’s successful formulation - can we honestly say it’s due to the developer?
The curves you posted above are not substantially different from the same film in some other developers. Are we in the realm of subtle aesthetic effects that cannot be measured? And if so, are they real?

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I had taken this as a compliment of my photography and not really a statement about the developer. The developer needs to support whatever artistic expression you are trying to achieve, and to that extent some credit is due, but you could achieve similar results by other means. It's fun with B&W that you have some control over the image produced by messing with chemistry. Finding an expression you like by starting from film and raw materials and getting images out at the end is rewarding, and that is enough for me.