Potassium Hydroxide in Parodinal?

[Olympus17]

I read on a blog that potassium hydroxide increases contrast. Is this possible?

 

[Donald Qualls]

Potassium alkali generally has a slightly higher pH than the analogous sodium compound (10.8 vs. 10.6, that I recall off the top of my head for carbonates) -- higher pH will increase developer activity, possibly enough to notice or measure with some films or developing agents.

 

[Olympus17]

In this case, potassium hydroxide can be used in the developer for contrast? If possible, could this be the same as grams of sodium hydroxide?

 

[Alan Johnson]

In this case, potassium hydroxide can be used in the developer for contrast? If possible, could this be the same as grams of sodium hydroxide?

I am not sure the hydroxide would give sufficient contrast.
Usually the contrast is attributed to hydroquinone in print developer:
http://www.pictorialplanet.com/advanced_photography/ansco-130.html
:

 

[Olympus17]

Metol is impossible, hydroquinone is close to it.

 

[Olympus17]

Is there any chemical that can be substituted for the metol? ??? If this were possible, all problems would be solved.

 

[Alan Johnson]

See post 8, you could try PaRodinal at 1+9 first.
https://www.photrio.com/forum/threads/easy-classic-paper-developer-recipe.88948/
If not happy add some hydroquonone to up the contrast.
Metol and p-aminophenol, the active developer in PaRodinal are chemically similar.

 

[Olympus17]

I think I will prepare my first Parodinal next week and try it on both film and paper. Thank you all so much for your patience and help.

 

[hol571]

@Olympus17 My potassium based para-rodinal formula (was clear initially but over time has developed a few small crystals - currently 3 yrs old):

based on 50mL scale (adjust your amounts accordingly)
3g - Acetominophen (I have access to pure acetominophen, but would recommend capsules over tablets)
8.89g - Potassium Metabisulfite
10.1g - Potassium Hydroxide
Distilled water to 50mL

(hydroxide amount was adjusted for the molar conversion of metabisulfite to sulfite)

 

[Donald Qualls]

And my Parodinal, based on an original acetaminophen developer recipe I found (most likely via a reference from APUG or Photo.net):

Parodinal LF: Low Fog Variant, fourth version, 22 September 2008


75 ml Water (110° F)
12 tablets @ 500 mg Acetaminophen (aka paracetamol, n-acetyl p-aminophenol)
20 g Sodium Sulfite (anhydrous)
8 g Sodium Hydroxide (anhydrous)
5 g Potassium Bromide

Water to make 100 ml

Note that this is a tenth of a liter -- and I may have misunderstood the request a few posts ago. It might have been asking for "clear" as in a transparent solution with no precipitate, rather than "clear" as in easy to understand and free from ambiguity.

Experience shows that this developer will keep quite well, and still works when there's just about enough left in the bottle to make your working solution, the color of cola, and despite the "rocks" of what i believe to be sodium sulfite crystals that form on the bottom as the concentrate ages. I've made it in batches as large as 500 ml, but counting and crushing the tablets is annoying. Too bad the only way to get acetaminophen in powder form in the USA seems to be to buy it in single-dose packets (Goody Powder and competitors) for Way Too Much, or set up an account with an overseas chemical supplier and import it by the tens of kilos; I'd like to make this in 500 ml batches all the time, but I'd rather weigh powder than count and crush sixty tablets...

The potassium bromide is optional; I jacked up the level over several iterations in an attempt to reduce the fog in my film, but p-aminophenol just isn't going to do that; there wasn't much difference between this version and the original with no KBr.

 

[Olympus17]

Thank you Donald Qualls. In the first message, what I meant was "clear " meaning easy to understand. But your explanations are very clear. What do you think the solution's shelf life is? Could it be a few years? Also, I wish I had the opportunity to see a few of the photos you prepared with this solution. I am really curious. I am a philosophy teacher and I want to teach analog photography to my students. Of course, if schools can be opened. As you know, corona has closed schools. I bought several enlargers and I can print up to 6x9. For now, I can print 18x24 cm from 35mm negative.

 

[Olympus17]

@ Hol571. Thank you for your calculations. I will keep this formula in my mind as well. As I purchase the necessary chemicals, I think of making developers with different formulas and comparing them with each other. Still, it seemed to me that the amount of potassium hydroxide for 1 liter would be high. Or this thought is about not knowing chemistry

 

[Alan Johnson]

Some of the old links to usenet, later google groups, are broken. Here is one I dug up regarding the apparent origin of this synthesis in 2004. There may be others.
https://groups.google.com/g/rec.photo.darkroom/c/RSXUMhD3sEQ/m/BQnHyfwJ8kMJ
It is thanks to Donald Qualls later work that PaRodinal became more widely known.

 

[hol571]

It's just a chemistry thing. For the 100mL scale, my formula and the formula posted by @Donald Qualls have the exact same final molar equivalents of sulfite, hydroxide, and acetominophen. We just arrive there through different counter ions of K or Na and metabisulfite vs sulfite.
First KOH is 1.4x more mass than NaOH at the same molar equivalent, ie 14g KOH and 10g NaOH are both 0.25mol.
Second, in my formula I start with metabisulfite which must be converted to sulfite (K2S2O5 +2KOH -> 2K2SO3 + H2O) hence the higher initial amount of hydroxide needed.

If you were to use potassium sulfite instead of metabisulfite, for 50mL it would be 5.61g KOH and 12.66g of potassium sulfite

As far as stability, I just used mine again a few weeks ago and it worked fine (made it in 2017), and I've just had it stored in a clear polypropylene tube at room temp.

Also, while not explicitly mentioned, you should let the developer sit for a bit before use to make sure the conversion of acetominophen to 4-aminophenol has gone to completion (most recipes suggest a few days to a week)

Hope this makes enough sense, and once you get your chemicals, if you need help converting the formula between chemicals with the different counter ions (like using potassium metabisulfite with NaOH or sodium sulfite with KOH) feel free to reach out

 

[Olympus17]

@ hol571 I wish I had followed the chemistry lesson more carefully in high school. The information you provide will be important reference. I hope I can share the solution and the negatives with you here as soon as possible. I will keep my notes very carefully while preparing the solution.

 

[Raghu Kuvempunagar]

Does anyone have a clear parodinal formula?

If you can get para aminophenol base at your place, you may want to try Gainer's EZ Rodinal.

 

[grain elevator]

Thank you Donald Qualls. In the first message, what I meant was "clear " meaning easy to understand. But your explanations are very clear. What do you think the solution's shelf life is? Could it be a few years? Also, I wish I had the opportunity to see a few of the photos you prepared with this solution. I am really curious. I am a philosophy teacher and I want to teach analog photography to my students. Of course, if schools can be opened. As you know, corona has closed schools. I bought several enlargers and I can print up to 6x9. For now, I can print 18x24 cm from 35mm negative.

Cool that you're so free to teach what you want!
But with kids, it would be better to use a developer with lower pH, i.e. not containing hydroxide. Or do you have goggles and gloves for all of them?
Maybe you can talk to the chemistry teacher about ingredients and safety?

 

[Murray Kelly]

Just a note for those interested, the bottle of Agfa Rodinal (10 y/o) I purchased here has an extra sticker for the Australian market. Inter-allia it states that it contains 41g/L of KOH.

 

[Olympus17]

Cool that you're so free to teach what you want!
But with kids, it would be better to use a developer with lower pH, i.e. not containing hydroxide. Or do you have goggles and gloves for all of them?
Maybe you can talk to the chemistry teacher about ingredients and safety?

Hi. Of course, we will work with the necessary security measures. The opposite is not possible.

 

[Raghu Kuvempunagar]

Just a note for those interested, the bottle of Agfa Rodinal (10 y/o) I purchased here has an extra sticker for the Australian market. Inter-allia it states that it contains 41g/L of KOH.

Interesting! That's almost the same amount of Potassium hydroxide in Gainer's EZ Rodinal! Gainer used 38.4g/l.

 

[Donald Qualls]

What do you think the solution's shelf life is? Could it be a few years? Also, I wish I had the opportunity to see a few of the photos you prepared with this solution. I am really curious.

I'm not at home; I have scans stored on my home computer from at least three different films in Parodinal, and I'll try to remember to post some tonight. My experience is that the 100 ml batch size, stored in a 1 pint mason jar (pretty large diameter and lots of trapped air for the volume of concentrate) lasted at least six months. Stored in a container that would allow excluding air, it might well last multiple years, but it's easy enough to mix I wouldn't make more than you expect to need.

 

[Anon Ymous]

Just a note for those interested, the bottle of Agfa Rodinal (10 y/o) I purchased here has an extra sticker for the Australian market. Inter-allia it states that it contains 41g/L of KOH.

Interesting, thanks for sharing. Does it also list p-aminophenol concentration?

 

[Olympus17]

I'm not at home; I have scans stored on my home computer from at least three different films in Parodinal, and I'll try to remember to post some tonight. My experience is that the 100 ml batch size, stored in a 1 pint mason jar (pretty large diameter and lots of trapped air for the volume of concentrate) lasted at least six months. Stored in a container that would allow excluding air, it might well last multiple years, but it's easy enough to mix I wouldn't make more than you expect to need.

I wonder the photos. I ordered the chemicals today. It will reach me in a few days. While preparing the solution, I can ask you again for help. Thank you.

 

[Donald Qualls]

Okay, here are a couple examples developed in Parodinal.

Pentax Spotmatic SP, Super Takumar 50mm f/1.4, Tri-X, Parodinal 1:50

Canonet 28, .EDU Ultra 100, EI 400, Parodinal 1:50

Zeiss Ikon Ideal, 13.5cm f/4.5 Tessar, Fomapan 100, Parodinal 1:50

 

[Nige]

And my Parodinal, based on an original acetaminophen developer recipe I found (most likely via a reference from APUG or Photo.net):

Parodinal LF: Low Fog Variant, fourth version, 22 September 2008

75 ml Water (110° F)
12 tablets @ 500 mg Acetaminophen (aka paracetamol, n-acetyl p-aminophenol)
20 g Sodium Sulfite (anhydrous)
8 g Sodium Hydroxide (anhydrous)
5 g Potassium Bromide

Water to make 100 ml

Based on a formula that referenced Donald’s page (that is no longer available?), I ran around the house and found the following (which was a ‘half’ batch)

125ml tap water (forgot to use distilled)
15x 500mg Panamax tablets (Paracetamol)
25g ‘Sparkle’ Dishwashing powder (amazingly I couldn’t find actual composition but found one image of the label it contains Sodium Carbonate & Sodium Metasilicate, ratio unknown. The label of my tub doesn’t have this info.)
20ml ‘Drain Clean’ liquid (16% Sodium Hydroxide W/W)

I mixed as specified and let sit for 3 days. Liquid was very dark brown but no precipitates. I diluted some 1:9 and dipped some very old Ilford P400 film in (in room light). It developed some density after about 7mins so I grabbed some FP4 and stuck that in. After 10mins it had good density. Next I rolled some of the FP4 into a cassette and ran it through a camera. I decided to dilute that 1:29 for a more ‘rodinal’ like dilution, and extended the development time to 15mins. Got very faint negatives. Rolled another and developed it at 1:9 for 10mins. Negs came out with nice density. Next test was a roll of J&C Pro100 I’ve had for a long time. I had developed a roll of this in original Rodinal a few days earlier and it had come out fine (although has many defects) . Decided to dilute 1:14 and develop for 15mins. Absolutely nothing. No edge markings what-so-ever. At this point I threw some paper (MGIV RC) in this solution and it developed somewhat (quite wishy-washy and maybe 1/3 of what would be max black)

So… is this an indication I can’t dilute more than 1:9? Doesn’t contain enough developing agent? The ‘Sparkle’ is one ingredient I was very dubious about but I haven’t found anything ‘local’ with sodium sulphite as the ingredient but have Sodium Carbonate as a pool chemical. Would this be better? In Stage 4 lockdown so can’t go anywhere except the grocery store to get anything (and we don’t have the range America seems to sell)

I have the following pool chemicals if any of them are useful substitutes?

Soda Ash (Sodium Carbonate 1000g/kg)
Stabiliser (Isocyanuric Acid 1000g/kg)
Hardness Increaser (Calcium Chloride 990g/kg)
Outdoor Cleaner (Sodium Hypochorite 50g/L)
Algacide (Benzalkonium Chloride 150g/L)
Calcium Hardness Decreaser (Hydroxyethylidene Diphosphonic Acid comple 370g/L)

I also bought some Caustic Soda in powdered form as suggested in original receipe.

Any thoughts appreciated…