PC-Glycol and Density

scott_wainer · April 5, 2009

Hi All -

I'm just getting back to film photography after several years of digital, am new to this forum, and look forward to any and all help you can give. I apologize in advance as this will be a long post.

I plan on shooting a mixture of 35mm, 120, 4x5, 5x7, and 8x10 and was looking for a general developer that is easy to mix, sharp, fine-grained, and provides long life. After searching the net, I have decided on Patrick Gainer's PC-Glycol film developer. I ordered fresh chemicals, mixed up a variation (see below), and ran several speed tests. The problem is that it seems to be lacking speed and density compared to D-76.

PC-Glycol Formula -

Solution A:

Ascorbic acid 10 gm

Dimezone S .36 gm

Propylene Glycol 100 ml

Note: The increased amount of Dimezone S is because I read that it is not as active as Phenidone. To maintain the same level of activity, it was recommended to use 1.4x the amount of Phenidone.

Solution B:

Sodium metaborate 30 gm

Distilled water 100 ml

I ran a speed test on 2 rolls of ISO 100 35mm film by exposing a white card at EI 100, 50, and 25 on the same roll. I centered the exposures on Zone V at 1/15 second:

ISO 100 exposure example:

0 - 1/500 - F/16

1 - 1/250 - F/16

2 - 1/125 - F/16

3 - 1/60 - F/16

4 - 1/30 - F/16

5 - 1/15 - F/16

6 - 1/8 - F/16

7 - 1/4 - F/16

8 - 1/2 - F/16

9 - 1/2 - F/11

10 - 1/2 - F/8

I did the same for ISO 50 and 25 opening up 1 stop for each increase in exposure.

For the PC-Glycol, I developed in a small tank at a 1+1+100 dilution for 12.50 minutes at 70F. Agitation was continuous for the first 30 seconds plus 10 seconds every minute thereafter. The film was rinsed for 30 seconds, fixed for 3 minutes in TF-3, washed for 10 minutes, given a 30 second dip in photoflo, and hung up to dry.

I did the same for the second roll but developed it in D-76 1+1 for 10.50 minutes at 70F as a control.

I took densitometer readings and plotted the curves:

Zeroed the densitometer.

Read film base (fixed, undeveloped) at 0.34.

Read film base+fog at 0.37.

Zeroed the densitometer at film base+fog.

PC-Glycol 1+1+100 (12.50 at 70F) Zone 0 - X readings:

ISO 100

0.00 - 0.01 - 0.05 - 0.13 - 0.26 - 0.44 - 0.63 - 0.81 - 0.96 - 1.08 - 1.20

ISO 50

0.01 - 0.04 - 0.13 - 0.25 - 0.42 - 0.62 - 0.79 - 0.94 - 1.04 - 1.14 - 1.26

ISO 25

0.03 - 0.10 - 0.24 - 0.40 - 0.60 - 0.80 - 0.95 - 1.06 - 1.20 - 1.29 - 1.40

D-76 1+1 (10.50 at 70F) Zone 0 - X readings:

ISO 100

0.04 - 0.10 - 0.25 - 0.46 - 0.66 - 0.86 - 1.10 - 1.28 - 1.45 - 1.64 - 1.78

ISO 50

0.09 - 0.24 - 0.43 - 0.63 - 0.86 - 1.08 - 1.25 - 1.37 - 1.50 - 1.77 - 1.82

ISO 25

0.20 - 0.41 - 0.62 - 0.84 - 1.06 - 1.29 - 1.45 - 1.61 - 1.73 - 1.86 - 1.89

The target density range I was looking for was 1.00-1.10 using 0.10 for the Zone I speed point and a development point of Zone VIII. As you can see the PC-Glycol does not reach the speed point until ISO 25. Compared to the readings I got from D-76, something is off.

Searching the web, I found that most dilutions of PC-Glycol are listed as 1+50. Could the 1+1+100 dilution I used cause the speed point to be off by as much as it is? Would doubling the dilution to 1+1+50 bring me up to where I want to be? I ask this first, before further testing, as it would save time and expense if someone could point me in the right direction.

Thank you in advance!

trooper · April 5, 2009

FWIW, I went down the trail of Dimezone-S when using some of Ryuji Suzuki's formulas that called for it. The first time that I used it, it seemed to behave as expected. My initial supply went off very quickly. The next batch was little better and the following arrived discolored and would not function for me. When I would use phenidone, I got predictable results. My experience may have nothing to do with your current episode but I got very gun-shy of Dimezone-S from the brief set of experiences that I had.

As to your questions.... I would certainly do a follow-up at the 1:50 to see if you had been over the threshold of activity level for the Dimezone at the dilution you were at. Some years back, I recall trying a short batch of PC-Glycol and don't recall a lack of activity. I returned to darkroom activity about 5 years ago and had a lot of fun doing home-brews and seeing the different type of results available. After tons of experimenting (okay, I still mess around a bit), my go-to soup was PyroCat-MC. The various versions of PyroCat differed very, very little but the MC seemed like it may be more stable for storage, etc so I settled on that variant. The two main reasons that I found that I favored PyroCat was that the negatives scanned much easier for me and traditional darkroom prints printed with so much less manipulation because of the good shadow detail and controlled highlights. I only mention this to you as I wish someone would have done so for me early on in my testing.....

paul_verizz · April 5, 2009

Boy, that Google bot gets around! Here I am doing some research on PC-Glycol and it picked up your new post.

I mixed up some Phenidone based PC the other night; I've not had a chance to try it. I used Prestone antifreeze for the glycol. I had spent a lot of time agonizing over getting pure stuff by mail, but the Prestone specifically states no borates, no silicates, no other things which I remember being in antifreezes long ago. The only ingredients besides ethylene and diethylene (?? IIRC) glycols are two sodium salts which I presume to be the metal protectorants. From my amateur chemist perspective, neither sound photographically active.

So laying out Phen/AA/SS/Kodalk quantities from what is presumed to be the official formula for Xtol, and then PC, I discovered a major difference at working dilutions. The reason I want to stick near Xtol is that Kodak already did all of the time-temperature work, dilutions up to 1:3 on the German chart. No sense reinventing the darkroom.

If one uses the amount of ascorbic acid/ascorbate in Xtol 1:3, we find, still, 3 grams of AA. Using the 10g of AA in - and this is critical - an often quoted PC-Glycol formula, there is only .2g!

Note also that Gainer uses, at 1:50, less working chemicals and more pH, using carbonate instead of Kodalk. At 5g/l, that's a big pH difference. But hard to see it making up for 1/15 the AA.

So happening to come across - again - Gainer's original article about preservation of AA developers, he concludes that the mix should be in a glycol, and then he gives his little simple formula: .25g Phenidone (still a lot more than Xtol, in all probability) and 100g AA! Ten times as much as the formulas floating around elsewhere. That would give 2g at 1:50. The "missing" gram from Xtol might be substituted, in effect, by the higher carbonate pH.

I am gong to internet research this discrepency some more, and in all probability will add a lot more AA to my PC-Glycol! I also think that Kodalk/Sodium Metaborate/Kodalk Balanced Alkali was used in Xtol for a reason, that being a better buffered solution. Carbonate has no buffering ability.

Paul

Alan Johnson · April 5, 2009

The official version of PC-Glycol I believe uses 5g/L sodium carbonate:

<a href="http://www.unblinkingeye.com/Articles/Preserv/preserv.html">http://www.unblinkingeye.com/Articles/Preserv/preserv.html</a>

Using Delta 100 I found this gave my personal EI=100 compared to 64-80 for D-76.But it is grainy.

Grain can be slightly reduced using lower pH metaborate maybe, but if the results suggest loss of film speed ,it could be that it would be better to control grain and film speed with sulfite and ascorbate.

Xtol pre-packed or Mytol for home-brew could be worth a try,they have sulfite to control the grain and the dimezone(or phenidone)-ascorbate gives good film speed.

paul_verizz · April 5, 2009

That's the original story I mentioned. 100g AA.

If we mix up separate PC, Sulfite, and accelerator, the combinations are endless.

I've never heard anyone complain about Xtol grain or sharpness being mushy, so despite Mr. Gainer's horror at using sulphite, that's where I'm heading. If nothing else, sulfite opens up development centers in the silver bromide grains which normally translates into increased speed.

scott_wainer · April 5, 2009

Paul,

The quantities in the article are based on 1000 ml of solution. That works out to 10gm AA and 0.25gm Phenidone in 100ml of Glycol.

I tried making a glycol solution that resembles the working strength of Mytol 1+1; an X-tol clone. It had:

Solution A - Stock

Ascorbic acid - 25 gm

Phenidone - 0.36 gm

Propylene glycol - 100 ml

Solution B - Working

Sodium sulfite - 15 gm

Sodium metaborate - 1 gm

Sodium metabisulfite - 0.75 gm

Distilled water - 500 ml

Diluted 10ml of A to 500 ml of B, all I got was blank film. My film speed test showed a reading of 0.08 for Zone X. Re-reading all my notes, I think the problem is that the additional AA dropped the pH of the solution and caused it to become inactive (live and learn).

In another test, I kept the original part A (see my first post) and changed the part B to:

Solution B - Working

Sodium sulfite - 6 gm

Sodium metaborate - 15 gm

Distilled water - 500 ml

The dilution was 5ml Part A to 500ml Part B. This gave me readings of 0.07 and 1.30 for Zones I and X.

Perhaps I'll work further on this track and see where it takes me; increaseing the SS and/or the Metaborate.

scott_wainer · April 5, 2009

Oops, just caught a mistake - I should have said:

The dilution was 5ml Part A to 500ml Part B. This gave me readings of 0.07 and 1.30 for Zones I and VIII.

Sorry.

paul_verizz · April 5, 2009

Scott, I must be having a major brain synapse malfunction. Forgive me Great Yellow Father, for I have sinned. Apparently slipped a decimal cog. Thanks.

Reworking my calcs for a 1:50 dilution, that's still sort of weak. Obviously not so much as I thought, but still weak. Two grams of AA is the same as Xtol at 1:5, although the Phenidone is double what is believed to be in Xtol. (I've read the patents, but there is so much of "In a range of" that someone with greater skills and equipment must determine that actual point. A formula "for Xtol" that I copied - oh, damn, using my brain again - has 85g sulfite, 12g ascorbate, .15g Dimezone, 3g sodium metabisulfite. I don't recall the source, but it looks good insofar as the patents.) If we can say that Dimezone and Phenidone are roughly equal in activity per weight, then Patrick has doubled the Phenidone per Ascorbic Acid. Again, there is about a 90% equivalence between AA and the salt, nothing that would make quantum leaps of effectiveness.

You said, "I think the problem is that the additional AA dropped the pH of the solution and caused it to become inactive." I'm not sure sure that happens. I mixed some AA with sulfite, I think 12g and 60g accordingly, and the pH was a smidge under 7. I was shocked, I expected a lot lower. Maybe the sulfite did some coupling with the AA to make ascorbate, I dunno. But I"m down other roads now so that will just have to remain a mystery.

I'm going to take Gainer's PC-Glycol using the AA as a comparative to Xtol, and start from there. I'll use metaborate for the alkali as Kodak does for Xtol, and add sulfite to equivalence, too. Maybe I'll have chance this weak to try out. Nothing fancy, no densitometers, just eyball and an 8x loupe.

paul_verizz · April 5, 2009

"This weak...." Obviously still having brain problems!

scott_wainer · April 5, 2009

Craig,

I just took your recommendation concerning the Phenidone and ordered some. I'll re-run my tests and see where it gets me.

Back before I went digital, I tried Pyrocat-HD but could never figure out how to use it with 35mm to get acceptable results. I don't have a densitometer that reads the stain for speed and development tests so I was either under/over exposing and developing. I found it easier to use a non-staining developer; though it has meant sacrificing grain and highlight compensation.

I print my negatives with silver gelatin papers and historic processes. Using a developer like Pyrocat would be a great help in this respect with sheet film but currently I just use Lith film for inter-positives and final negatives as I am loath to sink additional money into a color/UV densitometer.

Alan,

I noticed several people had the same comment with respect to the carbonate/grain issue. That was why I went with the metaborate. The other concern I had was in adding sulfite to the mix for finer grain but at the sacrifice of sharpness. I am probably too concerned with sharpness and grain for my own good, but I strive for the best of both worlds.

I tried both X-tol and Mytol but had both go bad overnight. I liked the negatives and prints I got with them so I went looking for a developer that was similar but with a longer shelf-life. I like what I have read about PC-Glycol but as they say, the proof is in the execution.

Paul,

I don't think you have much to worry about from the Great Yellow Father. I think he turned his back to those not completely, 100% embracing the "Digital Age". Did I say that? SHAME ON ME.

Seeing that Glycol replaces Sulfite as the preservative, the only reason to add it to the mix is in an attempt to reduce the grain; but at the sacrifice of sharpness. Saying this, I'll admit to having a 50 lb pail of sulfite in the darkroom. On the other hand, I read somewhere that sulfite also helps with film speed by uncovering latent image sites for development.

I hope it works and ask that you post the results as I may try it if it works. I don't think I'll have time this week for more testing but there is always the weekend.

larrydressler · April 5, 2009

I use HC-110 it is much cheaper... but then again some day I won't be able to get it so I will look to your results.

Alan Johnson · April 6, 2009

Scott,

It is mentioned that Xtol and Mytol went bad overnight.

If you wish to pursue this, I would say they keep OK in absence of air.

I have re-used Xtol stored in a full 500ml glass bottle 5 times before throwing it out,over a period of 2 months.Unused, the full glass bottles of Xtol kept for 22 months.

I put it back in the bottle after it has done its developing thing and top up with inert gas.

scott_wainer · April 6, 2009

OK folks,

I did a little research today and ran speed tests on Arista.edu 100 and Efke KB25 films using the following formula:

Sol A - Stock

Ascorbic acid - 10 gm

Dimezone S - 0.36 gm

Propylene glycol - 100 ml

Sol B - Working

Sodium sulfite - 6 gm

Sodium metaborate - 5 gm

Distilled water - 750 ml

The dilution was 10 ml of Sol A + 750 ml of Sol B at 70F. Agitation was continuous for the 1st 30 seconds and 10 seconds every 2nd minute thereafter (almost minimal agitation) for both films. I processed the Arista.edu for 12.50 minutes and the Efke for 8.50 minutes.

I am happy to report that doubling the Sol A from 5 to 10 ml worked wonderfully. I was able to get EI 80 for the Arista.edu and EI 20 for the Efke with a DR of 1.10.

I think I'll be able to get N-1 development when needed simply by changing Sol B to 1000 ml (same chemical quantities) with another minute or two of development without having to change the EI rating. Has anyone tried this?

Thanks for all the help; it's much appreciated!

scott_wainer · April 6, 2009

Larry,

With the way Kodak is moving, that day might just be soon.

I don't have any experience with HC-110 so I really can't comment on it. I moved away from store bought chemistry more than 10 years ago as I prefer to mix my own; I enjoy the mixing.

If you do move away from HC-110 I hope my information helps.

larrydressler · April 6, 2009

I understand I have the darkroom cook book .... thank you it is just that the stuff you were making reminded me of HC-110 with the glychol in it.

Thank you

scott_wainer · April 6, 2009

Alan,

My last experience was with Mytol. I mixed a liter and used 500 ml to develop 2 rolls at 1+1 one-shot. The remaining 500 ml was stored in a 550 ml glass bottle with a very tight cap. I developed 2 rolls the next day and ended up with extremely thin negatives. That was very surprising.

After reading Patrick Gainer's article "Preservation of Ascorbate Developers" on unblinkingeye.com and not wanting to tempt fate again, I decided to go the Glycol route. I even make my stock solutions of Phenidone/Dimezone S with it. Since I have the Glycol on hand, as well as Ascorbic Acid for my print developers, the next step was to try PC-Glycol.

I say if it works for you, go for it. As for me, now that I've pretty much figured out PC-Glycol, I'll stick with it and see how it does with actual images. I can always modify it to get what I need.

scott_wainer · April 6, 2009

Larry,

The Darkroom Cookbook is my Bible.

Have you read Patrick Gainer's article "Preservation of Ascorbate Developers" on unblinkingeye.com? There is a interesting part about stock HC-110 not developing film unless water is added.

jordan_w. · April 6, 2009

PC-Glycol is near and dear to my heart and I used it almost exclusively for quite a while before moving on to other developers. I always liked the results I got, though I did find that I lost some film speed with certain films, and the images -- while sharp -- came out somewhat grainy in my hands.

The grain is partly a result of the high alkalinity of working solutions of PC-Glycol. As Paul pointed out earlier in this thread, working solutions of PC-Glycol are comparable (though not identical) in ascorbate and phenidone concentrations to XTOL at its 1+3 dilution. However, PC-Glycol working solutions are also much more alkaline (pH > 10 If I recall correctly, vs. pH ~ 8 for stock XTOL, slightly lower when diluted). PC-Glycol thus tends to make up for a low developing agent concentration with high alkalinity. One side-effect of this is that it's easy to exhaust the developer, which I suspect is what happened in Scott's 1+100 working dilution experiment. There was probably just not enough developing agent in the solution to build up sufficient density (think "XTOL 1+7").

Using metaborate (or triethanolamine, as in PC-TEA) as an activator in place of sodium carbonate gives a lower working pH (around 9, still higher than XTOL) so developing times tend to be longer, but in my experience the resulting grain is finer. (The pH values are approximate -- I did measure them with a good pH meter, but it's been a couple of years and my notes are buried somewhere).

There seem to be an almost infinite number of permutations of the ascorbic acid / phenidone / base system out there (with or without sodium sulfite). You can take the PC-Glycol stock solution and get to something close to XTOL by mixing it at more than double strength and adding sodium suflite. pH control is key if you want to use XTOL times and film speeds. I find it easier just to use something I call "Instant MYTOL", a four-component simplified version of MYTOL. My original post describing it is at <a href="http://www.photosensitive.ca/wp/archives/50">http://www.photosensitive.ca/wp/archives/50</a> or you can just Google around and find other places where I've described it. It's worked quite well for me so far -- quick to mix and I've used XTOL times and dilutions with great success on a variety of films.

paul_verizz · April 6, 2009

I wonder why you aren't getting full ISO with a developer type that often gives greater than box speed.

Another possibility is that despite many lovers of no-sulfite PC, sulfite remains useful to open up development centers in Xtol and maybe is not so much a silver solvent. Especially at dilutions which would put sulfite in the working strength of about 20g at 1:3. Not sure why you put 6g in your Part B at all.

Let me throw into this discussion the patent formula, verbatim: (I've noticed that many patents have missing commas and other formatting issues. Like this one, why would the "0.2g" of Dimezone be inserted into the chemical name????? Ditto the acetic acid.

Part A (Dry Formulation) Sodium sulfite 10 g, Diethylenetriaminepenta- 1 g acetic acid (water softener???), pentasodium salt Sodium metaborate (8 mol) 4.0 g, 4-Hydroxymethyl-4-methyl-1- 0.2 g phenyl-3-pyrazolidone (Dimezone) Part B (Dry Formulation): Sodium sulfite 75 g Sodium metabisulfite, 3.5 g Sodium isoascorbate 12 g

End result:

85 g Sodium Sulfite 3.5 g Sodium Metabisulfite 12 g (Sodium) isoascorbate (Sodium Erythorbate) .2 g Dimezone S 4 g Sodium Metaborate (Kodalk)

I presume the Sodium Metabisulfite is a pH adjuster. While a preservative like its sulfite cousin, at this amount it doesn't matter. I believe Dimezone is used instead of Phenidone for easier dissolving. Or maybe Kodak has the patent!

jordan_w. · April 6, 2009

The diethylenetriamine-pentaacetic acid is a chelating agent, a cousin of EDTA. Its purpose is to prevent premature oxidation of the ascorbic acid by chelating metal ions (usually iron(II)) that catalyze this reaction.

The sodium metabisulfite is a silver solvent / preservative like sodium sulfite, but in "acid" form. Sulfite and metabisultie together form something of a buffer system.

paul_verizz · April 6, 2009

Gosh, maybe I was right. According to this thread Dimezone is indeed a Kodak product. http://leica-users.org/v31/msg02476.html

The poster also says 20% less active than Phenidone, I guess your mileage may vary.

paul_verizz · April 6, 2009

I just tried to make a simple post and when I submitted it, this is what I got. Oh yeah, clear as mud:

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We had a problem processing your entry:

<ul>

Because of abuse by spammmers, we can't accept submission of any HTML containing any of the following tags: <code>applet area base body button div embed fieldset font form frame frameset head html iframe ilayer input layer link marquee meta object option pre script select span style textarea /applet /area /base /body /button /div /embed /fieldset /font /form /frame /frameset /head /html /iframe /ilayer /input /layer /link /marquee /meta /object /pre /script /span /style</code>

</ul>

Please back up using your browser, correct it, and resubmit your entry.

scott_wainer · April 7, 2009

Jordan,

Your site was one of the first I came across when I started researching for a developer. I thought about the Mytols but dismissed them due to my failures with X-tol/Mytol (as I stated above). I liked what I read about PC-Glycol and decided to pursue that avenue. One of the reasons I went this way was hearing that it was similar to X-tol/Mytol and I really liked the images I got from them. That, combined with the shelf-life, was just too much to pass up.

The funny part about the 1+1+100 dilution is that I read a post on APUG by Sandy King where he was getting ES 1.40 with that dilution on ISO 100 film at 10 minutes, 72F using rotary development. Looking back, I see that he didn't specify solution quantity. You are probably right in that I didn't have enough Sol A (I used 5 ml in 500 ml). Sandy may have used 10 ml in 1000 ml for his test which would account for the difference between my first and last tests.

I may try TEA in the future as I am all about grain-less images but for now I want to see how the images look with the current formulation.

scott_wainer · April 7, 2009

Paul,

The difference in EI vs. ISO could just be my meter as I'm only off by about 1/3 stop. I don't TTL meter, I use a spotmeter and I haven't had it calibrated.

As for the sulfite issue, it was my understanding that it opened up the development centers because it was a silver solvent. I would rather not have it in the soup because it is said to impair sharpness to a degree and I want as much sharpness as I can get. I only included the 6 gms because I when I first started to use Mytol I diluted it 1+2 and use 300 ml per roll one-shot and I liked the images I got though the negatives took forever to develop. I later changed to a 1+1 dilution and used 500 ml one-shot. I thought adding 6 gms (what was in the 1+2 dilution) might help the film speed without harming the sharpness. Not having a chemistry background, my thinking could be flawed (it might not be enough to make a difference).

The quantity being listed in the middle of the chemical might just be a typo that wasn't caught.

jordan_w. · April 7, 2009

Scott -- You can mix up Instant MYTOL in an organic solution by dissolving the phenidone and ascorbic acid in a mixture of triethanolamine and ethylene or propylene glycol. The instructions are in the first post at <a href="http://www.apug.org/forums/forum223/33880-instant-mytol.html">http://www.apug.org/forums/forum223/33880-instant-mytol.html</a> This approach gets around the shelf life problem quite nicely and was the way I used Instant MYTOL for the first year or so.

After I ran out of my Instant MYTOL organic stock solution I started mixing it straight in water, as needed. With only four ingredients (I pre-dissolve the phenidone as a propylene glycol stock solution -- the other three ingredients go into water effortlessly) it's very fast to mix.

I did get very nice results with both PC-Glycol and PC-TEA, but I never understood why people say that they're similar to XTOL (or MYTOL). They really aren't, as my earlier post describes; they both use ascorbic acid and phenidone as developing agents, but the developer concentrations and working pH values are very different. All three developers give nice images, but MYTOL takes the "edge" off the grain (while still being very sharp) and I found it easier to get clean scans for that reason. But "your mileage may vary", as they say!

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