My PC-512 Borax Developer

[relistan]

Hey everyone, I went mostly silent here for a year... life caught up. But early last year while working on two bath developers I ended up with a formula that I liked a lot for a single bath developer. It's not revolutionary at all, but I have been using it a lot and really like the results. You might, too, so I wrote up a post about it on my blog:

A Simple Phenidone/Vitamin C Concentrate Developer: PC-512 Borax

What follows is how I formulated a very nice developer that I have now used pretty much exclusively for the last year and a half. As it says in the title, I have called it “PC-512 Borax”. Creative name? No. But it is indicative of the formula. This nice developer is a secondary result of some...

imager.ie

It's a developer in the family of PC-Glycol. I have used that developer a lot and this one gives me substantially better results. It also has a much better Dmin than PC-Glycol, about 0.3 for Delta 100.

Update 28 Feb 2025: here's a page with starting times for development of various films: https://www.photrio.com/forum/resources/pc-512-borax-development-starting-times.462/

Here are some photos I developed with it (Delta 100)

 

[Donald Qualls]

Nice. I've got everything I need already in my darkroom, I may have to mix up some of this.

 

[relistan]

Nice. I've got everything I need already in my darkroom, I may have to mix up some of this.

Hey Donald, if you do, I'd be very interested in your results!

 

[Donald Qualls]

Got D-23 and DK-25R, EcoPro, and Flexicolor I need to get mixed, but I'll probably do the mix-your-own first and might manage to get this mixed this weekend. Then I have to work through twenty-plus rolls of backup, processing and scanning -- but I'll try to remember to come back and post results.

I've got the glycol, BTW, because I was going to make a phenidone stock solution for mixing FX-55 -- but this looks easier.

 

[relistan]

Got D-23 and DK-25R, EcoPro, and Flexicolor I need to get mixed, but I'll probably do the mix-your-own first and might manage to get this mixed this weekend. Then I have to work through twenty-plus rolls of backup, processing and scanning -- but I'll try to remember to come back and post results.

I've got the glycol, BTW, because I was going to make a phenidone stock solution for mixing FX-55 -- but this looks easier.

No worries, but if you get to it, I'd love to know how it went. It's definitely easy to mix. Just a lot of stiring, as per anything in glycol.

 

[BradS]

Thanks for sharing. Your results looks fabulous. Good work!

...the irony of that second photo is delicious.

 

[Donald Qualls]

If I get results that look as good as these, I might cancel plans to mix EcoPro and run replenished again.

I need to get a small bucket that can take hot water, then I'll use my sous vide to hold the water at 90 C or so to for mixing into the glycol. Might need to spring for some borosilicate beakers, too, but I've needed those for a while anyway.

Say, @relistan what are you getting for relative film speed with this (that is, lose 1/3 stop, box speed accurate, or like many PC developers, 1/3 or 2/3 stop speed gain)? "Not yet tested" is also a valid answer, of course...

 

[relistan]

Thanks for sharing. Your results looks fabulous. Good work!

...the irony of that second photo is delicious.

Haha, thanks Brad! Yeah I had titled it "Modern Color in Black and White"

 

[relistan]

If I get results that look as good as these, I might cancel plans to mix EcoPro and run replenished again.

I need to get a small bucket that can take hot water, then I'll use my sous vide to hold the water at 90 C or so to for mixing into the glycol. Might need to spring for some borosilicate beakers, too, but I've needed those for a while anyway.

Say, @relistan what are you getting for relative film speed with this (that is, lose 1/3 stop, box speed accurate, or like many PC developers, 1/3 or 2/3 stop speed gain)? "Not yet tested" is also a valid answer, of course...

That's a good idea to use for mixing. I actually put it in a glass container and microwave it about 15 seconds, then a few at a time until it gets hot enough. Be careful if you do it that way! I like your idea better.

I am shooting it at box speed and have been happy with that at the times posted. Depends on how you like your density. Delta 100 with a range of about 0.3 to 2.25 makes for pretty good prints. So far XTOL times - 15% seems to be about right.

Would definitely be interested in other people's results and times!

 

[Andrew O'Neill]

Excellent! I will give this a try. I do have a bottle of Glycol under the sink. Thank you for your hard work.

 

[BradS]

any suggestions for a good place to buy Proplyene Glycol?

 

[Donald Qualls]

any suggestions for a good place to buy Proplyene Glycol?

Amazon.

 

[relistan]

Excellent! I will give this a try. I do have a bottle of Glycol under the sink. Thank you for your hard work.

Hi Andrew, great, and thanks! If you try it out, let us know how it goes.

any suggestions for a good place to buy Proplyene Glycol?

Amazon is where I got it, but you can also find it at any place that sells supplies to people making their own vape mix I found out. It can also be found at suppliers of aromatherapy stuff.

 

[Andrew O'Neill]

Hi Andrew, great, and thanks! If you try it out, let us know how it goes.



Amazon is where I got it, but you can also find it at any place that sells supplies to people making their own vape mix I found out. It can also be found at suppliers of aromatherapy stuff.

Will do... and since it's in the same family as Xtol, I will have to compare them together

 

[Jay Schrotenboer]

Will do... and since it's in the same family as Xtol, I will have to compare them together

I sense another video coming!

 

[Andrew O'Neill]

I sense another video coming!

Stick another one on the list! It's like my never ending pile of negatives!

 

[John Wiegerink]

Pyrocat HDC-glycol and Xtol -R are my two main and favorite developers. PC-512 sound like it would be nice to have on hand for a one-shot Xtol type developer. Later this winter, when things are slow, I just might give it a try, but I think I’ll play with sodium metaborate instead of borax. Why? Well, it might be because I have a Kodak cardboard drum marked Kodak Kodalk with about 20lbs. of the stuff In it.

 

[albada]

Pyrocat HDC-glycol and Xtol -R are my two main and favorite developers. PC-512 sound like it would be nice to have on hand for a one-shot Xtol type developer. Later this winter, when things are slow, I just might give it a try, but I think I’ll play with sodium metaborate instead of borax. Why? Well, it might be because I have a Kodak cardboard drum marked Kodak Kodalk with about 20lbs. of the stuff In it.

If you have sodium metaborate lying around, and you're willing to dissolve chemicals into hot propylene glycol, you might try making some Mocon, which the OP references in his article. The Mocon article is here and here. Mocon was designed to give Xtol quality in a concentrate that lasts years when refrigerated or frozen. For both PC-512 and Mocon, you (1) create a PG-based concentrate, and (2) create a separate water-solution of an alkali. Mocon was tested on 11 films, all of which were measured with a densitometer and graphed, so films are known to attain box-speeds and have well-behaved H-D curves. One warning: I'm biased, because I am the inventor of Mocon.

@relistan : sodium metaborate will dissolve in PG, and borax has a similar composition, so it might dissolve in PG as well. If borax does not dissolve, you could try sodium metaborate in your formula instead, as John asked about. By dissolving one of those, you might be able to create a single concentrate to be used like HC-110 that yields D-76 quality. Folks would like that.

 

[Raghu Kuvempunagar]

@relistan : borax has a similar composition, so it might dissolve in PG as well. If borax does not dissolve, you could try sodium metaborate in your formula instead,

Blackandwhiteology

Blackandwhiteology (Blak-ən-wīt-tä-lə-jē) noun – 1. The study of photographic techniques in black and white. 2. The pursuit of rendering the world in grayscale. 3. The subtle and interpretive practice of capturing form and subject in monochrome. Black and white photos. Of anything. Of...

www.flickr.com

 

[albada]

@Raghu Kuvempunagar , thanks for posting the link to Jay DeFehr's PG110B. I didn't know that existed. The table below compares the formulas for PC-512 and PG110B. Both yield 100ml of PG-based concentrate, although PC-512 has not yet been mixed that way:

Chemical	PC-512 (@relistan)	PG110B (Jay DeFehr)
Borax	108	30
Ascorbic acid	12	10
Phenidone	0.5	1
Dilution	1:50	1:100

The 108 is 5 times the 21.7 g of borax in one liter of borax solution, because consuming 100 ml of concentrate at 1:50 will also consume 5 liters of borax solution. Is this calculation correct? That's far more borax than PG110B, and I doubt that much borax will dissolve in 100 ml of PG.

 

[Raghu Kuvempunagar]

I doubt that much borax will dissolve in 100 ml of PG.

No idea, but it would be interesting to compare results from the two developers at the same dilution, i.e. 1:50.

 

[relistan]

Pyrocat HDC-glycol and Xtol -R are my two main and favorite developers. PC-512 sound like it would be nice to have on hand for a one-shot Xtol type developer. Later this winter, when things are slow, I just might give it a try, but I think I’ll play with sodium metaborate instead of borax. Why? Well, it might be because I have a Kodak cardboard drum marked Kodak Kodalk with about 20lbs. of the stuff In it.

Give it a shot, John. You will want to match the pH since the low pH seems to be essential to grain outcome. But anything is worth a try! I don't know what further differences you might see.

@relistan : sodium metaborate will dissolve in PG, and borax has a similar composition, so it might dissolve in PG as well. If borax does not dissolve, you could try sodium metaborate in your formula instead, as John asked about. By dissolving one of those, you might be able to create a single concentrate to be used like HC-110 that yields D-76 quality. Folks would like that.

Thanks Mark. There are two issues with dissolving the borax in the Glycol (I did try). The first is that the amount of it that I'm using is too much for the volume of glycol, so you would need a lot more glycol and to use the developer less diluted. That might work, but having the water/borax solution is easy enough. The second possible problem is that borax and propylene glycol do form compounds together and I am not sure whether that is a desirable outcome photographically. I suspect that heating them together to get the borax to dissolve would speed that up and increase the amount that has reacted. But I never got that far to test because of the first problem.

Blackandwhiteology

Blackandwhiteology (Blak-ən-wīt-tä-lə-jē) noun – 1. The study of photographic techniques in black and white. 2. The pursuit of rendering the world in grayscale. 3. The subtle and interpretive practice of capturing form and subject in monochrome. Black and white photos. Of anything. Of...

www.flickr.com

Ah yeah, thanks Raghu. You always know all the nooks and crannies of the photographic Internet! I remember reading that a long time ago. Looks similar in intent. Quite a different arrangement of ingredients.

@Raghu Kuvempunagar , thanks for posting the link to Jay DeFehr's PG110B. I didn't know that existed. The table below compares the formulas for PC-512 and PG110B. Both yield 100ml of PG-based concentrate, although PC-512 has not yet been mixed that way:

The 108 is 5 times the 21.7 g of borax in one liter of borax solution, because consuming 100 ml of concentrate at 1:50 will also consume 5 liters of borax solution. Is this calculation correct? That's far more borax than PG110B, and I doubt that much borax will dissolve in 100 ml of PG.

I am pretty certain you can't dissolve all that borax. The reason I am using so much borax is because there is so much ascorbic acid. I added and mixed until I got to the pH I was looking for. I adjusted that a bit over time and landed pretty much back where I started. There were two things that drove that thinking, rightly or wrongly:

1. I read Gainer's work some years ago and he was pretty convinced that ascorbic acid has a solvent effect. I used PC-Glycol a bunch and while I like it, it has quite noticeable grain and noticeable base fog. In my two baths I tried just using more ascorbic acid, but then wasn't pleased with the results. Better base fog, and better grain but not good shadow detail. Adding more phenidone really helped with shadow detail.
2. To get the solvent effect with ascorbic acid (not ascorbate), you end up with a fair bit of it. Then you need either a strong alkali or a fair bit of weaker alkali. They don't seem to be all interchangeable. The borax seems to do something for grain beyond just adjusting the pH. I don't know if this is a compound between borax and ascorbic acid that is photographically pleasing or if it's just the borax itself.

I am glad that people are interested in what I did. If someone wants to try it out, or compare with Jay's formula, I would love to see the results. The same goes for other films or other dilutions. I worked until I was happy with what I had, but as others have shown, there are a lot of possibilities.

 

[relistan]

For what it's worth, here's a set of Delta 100 negatives developed yesterday, hanging to dry.

 

[John Wiegerink]

Give it a shot, John. You will want to match the pH since the low pH seems to be essential to grain outcome. But anything is worth a try! I don't know what further differences you might see.



Thanks Mark. There are two issues with dissolving the borax in the Glycol (I did try). The first is that the amount of it that I'm using is too much for the volume of glycol, so you would need a lot more glycol and to use the developer less diluted. That might work, but having the water/borax solution is easy enough. The second possible problem is that borax and propylene glycol do form compounds together and I am not sure whether that is a desirable outcome photographically. I suspect that heating them together to get the borax to dissolve would speed that up and increase the amount that has reacted. But I never got that far to test because of the first problem.



Ah yeah, thanks Raghu. You always know all the nooks and crannies of the photographic Internet! I remember reading that a long time ago. Looks similar in intent. Quite a different arrangement of ingredients.



I am pretty certain you can't dissolve all that borax. The reason I am using so much borax is because there is so much ascorbic acid. I added and mixed until I got to the pH I was looking for. I adjusted that a bit over time and landed pretty much back where I started. There were two things that drove that thinking, rightly or wrongly:

1. I read Gainer's work some years ago and he was pretty convinced that ascorbic acid has a solvent effect. I used PC-Glycol a bunch and while I like it, it has quite noticeable grain and noticeable base fog. In my two baths I tried just using more ascorbic acid, but then wasn't pleased with the results. Better base fog, and better grain but not good shadow detail. Adding more phenidone really helped with shadow detail.
2. To get the solvent effect with ascorbic acid (not ascorbate), you end up with a fair bit of it. Then you need either a strong alkali or a fair bit of weaker alkali. They don't seem to be all interchangeable. The borax seems to do something for grain beyond just adjusting the pH. I don't know if this is a compound between borax and ascorbic acid that is photographically pleasing or if it's just the borax itself.

I am glad that people are interested in what I did. If someone wants to try it out, or compare with Jay's formula, I would love to see the results. The same goes for other films or other dilutions. I worked until I was happy with what I had, but as others have shown, there are a lot of possibilities.

The reason I'm interested in PC-512 is that I would like to have a one-shot developer equal to Xtol-R with long keeping properties. I like and use Xtol-R a lot, but sometimes I just want to use a one-shot developer. It would be great to keep at my cottage instead of trying to lug Xtol-R up there.

 

[John Wiegerink]

If you have sodium metaborate lying around, and you're willing to dissolve chemicals into hot propylene glycol, you might try making some Mocon, which the OP references in his article. The Mocon article is here and here. Mocon was designed to give Xtol quality in a concentrate that lasts years when refrigerated or frozen. For both PC-512 and Mocon, you (1) create a PG-based concentrate, and (2) create a separate water-solution of an alkali. Mocon was tested on 11 films, all of which were measured with a densitometer and graphed, so films are known to attain box-speeds and have well-behaved H-D curves. One warning: I'm biased, because I am the inventor of Mocon.

@relistan : sodium metaborate will dissolve in PG, and borax has a similar composition, so it might dissolve in PG as well. If borax does not dissolve, you could try sodium metaborate in your formula instead, as John asked about. By dissolving one of those, you might be able to create a single concentrate to be used like HC-110 that yields D-76 quality. Folks would like that.

I remember all the posts on Mocon, but never tried it myself. From everything I read, you have a right to be biased. Xtol-R is about the only non-staining developer I use. I like the grain, mid-tones and box speed I get with it. If I could get box speed with dilute Perceptol I'd use that for almost everything and Pyrocat for the rest.