Making some Parodinal, but would appreciate more insight...

Dear all,

This would be my first post, but I've been hovering around here for about 2 years.

I've tried my best to read up as much as I could before posting, and I have gotten quite far in creating my home brew Parodinal developer. I now need to fine tune the recipe, but my non existent knowledge of chemistry combined with all the internet posts out there (at least the ones I've found and/or understood) are failing me to get what I want...

What I have stocked:
- Sodium Sulphite (anhydrous)
- Sodium Carbonate (anhydrous)
- Sodium Ascorbate
- Ascorbic Acid
- Paracetamol Powder (Ph Eur 7.0) - I bought this from a pharmaceutical manufacturer.
- Distilled water (I have a small distiller)
- Sodium Hydroxide. (small clean white flakes form the hardware store)

I own have a jeweller's scale measuring in 0,1gr increments, with a max of 500gr.
I also have a digital thermometer with a 15cm thin metal probe.

On Saturday (Aug 25th) I made my first two batches follwing ZorkiKat's method;

Parodinal Batch 25082012-01:
1) Sodium Sulphite (50gr) was added into 125ml of water and dissolved as best as possible. Much of it didn't.
2) Sodium Hydroxide (20gr) was mixed into a separate amount of water (100ml). This, once dissolved, reached a temperature of approx 49ºC.
3) Paracetamol powder (15gr) was added to Hydroxide mixture, which quickly dissolved and took on a clear pale pink colour. This solution was stirred and cooled in a cool water bath.
4) While cooling solution in Step 3. the solution suddenly became cloudy and viscous at +/- 23ºC, at which the temperature rose by +/- 0,4ºC.
5) At this point, the saturated sulphite solution (with all precipitation) was added to the thick and cloudy Hydroxide+Paracetamol mix. The end result soon became clear and took on a light amber colour. The liquid fas filled to 250ml mark with distilled water, and bottled. (Bottle was a cleaned 500ml R09 Rodinal bottle)

Parodinal Batch 25082012-02:
This batch was made in the similar way as 01, but...
1) 50gr of Sodium Sulphite was added to 150ml of water, mixed well, and 125ml was decanted and put aside (no sediment).
2) Sodium Hydroxide (20gr) was mixed into a separate amount of water (100ml). This, once dissolved, reached a temperature of approx 49ºC.
3) Paracetamol powder (15gr) was added to Hydroxide mixture, which quickly dissolved and took on a clear pale pink colour. This solution was stirred and cooled in a cool water bath.
4) The 125ml of saturated Sulphite solution was poured into the Hydroxide+Paracetamol while still hot, and stirred. The solution, which was clear in colour, was filled to 250ml mark with distilled water, and bottled. (Bottle was a 200ml amber glass bottle, filled to the brim and the difference was disposed of)

On Monday (Aug 27th) I made two more batches.
Parodinal Batch 27082012-01:
Same Procedure as Parodinal Batch 25082012-01:, except I used half the Sodium Sulphite this time.
Solution was clear and amber in colour.
(Bottle was a 200ml clear glass bottle, filled to the brim and the difference was disposed of)


Parodinal Batch 27082012-02:
1) 50gr of Sodium Sulphite was added to 150ml of water, mixed well, and 125ml of this was decanted.
2) The Paracetamol was mixed into the Sulphite solution, which didn't dissolve very well.
3) Sodium Hydroxide (20gr) was mixed into a separate amount of water (100ml). This, once dissolved, reached a temperature of approx 49ºC.
4) The Sodium Hydroxide solution was added to the Paracetamol+Sulphite mix, which dissolved fairly quickly into a clear and colourless solution.
5) The level was filled with distilled water up to 250ml, and bottled.
(Bottle was a 200ml clear glass bottle, filled to the brim and the difference was disposed of)

Here is a pic of the two solutions from Monday:



Now, the observations on Monday Aug 27th:
Parodinal Batch 25082012-01: Dark red probably due oxidation in bottle. Solution had longish crystals amongst the sulphite sediment.
Parodinal Batch 25082012-02: Colour not determined, but it certainly didn't seem darker than on Saturday. Many long crystals had formed at the base, and solution was clear. (Sunday evening showed no signs of any crystals!)

On Monday afternoon, I was annoyed by seeing so many crystals in Parodinal Batch 25082012-02:, so I emptied the bottle into a small measuring jug, and slowly added up to a total of 7gr NaOH, which slowly dissolved the crystals, but a new sediment formed soon after which resembled that of a saturated sulphite solution. The solution was put back into the amber bottle. Please don't ask me why I added the extra NaOH I though it was a good idea at the time. I have probably ruined a good thing here...

The observations on Tuesday morning Aug 28th:
Parodinal Batch 25082012-01: Crystals seem unchanged, but solution seemed a little darker
Parodinal Batch 25082012-02: The base of the bottle was now full of long crystals again. Solution colour unchanged and still clear.
Dead Link Removed

Parodinal Batch 27082012-01: No crystals yet. Solution is a clear amber colour with very feint and very little sediment.
Parodinal Batch 27082012-02: No crystals yet. Solution is a clear, slightly yellow in colour, with very feint and very little sediment, but a little more than Parodinal Batch 27082012-01:


OK, So, thanks to all that have made it this far...

To those who know more than I do about chemistry, and also to those with greater experience in making this home-brew, is there anything I have been doing wrong or something you recommend me to change? My greatest concern is the amount of crystal volume in Parodinal Batch 25082012-02:. Are these amount of crystals that normal? Is there any ingredient I should/could increase/decrease to minimise this crystal growth to minimum? - I realise these crystals play a role, and that they are good to have, but not so many right?

I realise that my asking help may come a little early and that I may seem impatient... forgive me

I will report back when Monday's batches have developed crystals, which is something I'm expecting to see by tomorrow morning.

Thank you for your time and any help would be greatly appreciated!

Martin

Today, given the good weather, exposed 3 rolls of 35mm film on a test scene. Images were bracketed 1-stop both ways. Film was EFKE 50, with intentions to develop the film for 6min in 1:25 dilutions.

Today, I cut two strips from a test film, and developed one in commercial R09 Rodinal (From MACO Germany). The other was developed in Parodinal Batch 25082012-01:.
The negs are drying as I type, but look almost identical. Scanned results will come later after negs have dried. Any difference will be noticeable in the scan.

Don't worry about the oxidisation. All Rodinal including clones and DIY types quickly get to this colour.


Steve.

Steve,

Thank you. It's not so much the colour I'm worried about, but rather the amount of crystals that form after day 2 of a bottled batch. They seem excessive.
I'll be developing the films with every batch hopefully, so at least I'll have visual representation of what I did...

I think there are reports of deposits in most types of Rodinal too.

What do refer to as excessive? Can you post a picture of a bottle with crystal deposits in?


Steve.

It's the last image in my initial post, but here it is again.
hard to see, but they occupy a large volume of the bottle
Dead Link Removed

http://photo.net/black-and-white-photo-film-processing-forum/00UxmB
Efforts to improve PaRodinal included reducing suspended solids and also crystals.
IMO they are not entirely successful,the clear form in the link deposits crystals eventually,they may be sodium aminophenolate.
So well done for your work but I don't think you will get a crystal free solution.
Making it clear does not IMO affect the developing properties but it looks better.

Alan Johnson said:

http://photo.net/black-and-white-photo-film-processing-forum/00UxmB
Efforts to improve PaRodinal included reducing suspended solids and also crystals.
IMO they are not entirely successful,the clear form in the link deposits crystals eventually,they may be sodium aminophenolate.
So well done for your work but I don't think you will get a crystal free solution.
Making it clear does not IMO affect the developing properties but it looks better.

Click to expand...

Indeed, it does look better.
The first batch already developed some negs, so it does work... :

Right, it's Wednesday morning here, and still no crystals in both Monday's batches. Hmmm
Parodinal Batch 27082012-2 has become a little more yellow since yesterday.

Here is a comparison image of commercial Rodinal R09 One-Shot (Purchased from MACO) and Parodinal Batch 27082012-2. (Link to the full res version is HERE)


Interestingly enough, the Parodinal developer created ever so slightly denser negatives, which is something I only noticed after scanning.

The negs were scanned on my Imacon 343. The film was EFKE 50, shot with Nikon F5 and 50/1.8D, exposed at 1/400sec f/5.6 as per incident meter reading, and developed in dilution 1:25 for 6min at 20ºC.
Apologies for the dark negs, I don't work with this film very often, so film speed rating developing times are taken using recommendation by massive dev.

Please note, these images come straight out the scanner, with only cropping applied. Sharpening was set to zero, and levels were kept as is at 0, 1.0, and 255.

Looking at the full res images it's hard to tell them apart.
The original liberated Rodinal formula used potassium not sodium though:
(there was a url link here which no longer exists)
It is said the sodium version is slightly softer working.
The PaRodinal that is sold in the Phillipines uses potassium.
In the clear version of Parodinal the crystals may take months to appear but disappear again in hot weather.
IDK if the potassium version avoids the crystals,but many potassium salts are more soluble than sodium salts.

Alan Johnson said:

Looking at the full res images it's hard to tell them apart.
The original liberated Rodinal formula used potassium not sodium though:
(there was a url link here which no longer exists)
It is said the sodium version is slightly softer working.
The PaRodinal that is sold in the Phillipines uses potassium.
In the clear version of Parodinal the crystals may take months to appear but disappear again in hot weather.
IDK if the potassium version avoids the crystals,but many potassium salts are more soluble than sodium salts.

Click to expand...

Yeah, I read that post before.
I can only get Potassium Hydroxide and Potassium Metabisulphite here, but I'm not sure what the minimum purchase quantities would be.

Is there a recipe I could follow with the Potassium Hydroxide and Potassium Metabisulphite?
(I'm going to start searching for one now...)

... OK.

Is this right?

Potassium Metabisulphite (32,2gr) + Potassium Hydroxide (25,8gr) + Paracetamol (15gr) + distilled water (250ml total finished volume)

One mole K2S2O5 (222.3g) plus 2moles KOH (112.2g) gives 2 moles K2SO3 (316.6) plus 1 mole water (18.0g)
Sorry I don't have time to do the complete calculation at the moment.
AFAIK the potassium version of Parodinal formula is not published,you have a research project.

Fantastic! Thank you.
I will get onto procuring the chemicals first, and then doing the necessary calculations.
I hope the supplier is willing to sell me the materials in 1 or 2kg packets!

Hi Martin,

I make this formula using Panado capsules and potassium hydroxide, and call it Panadonal-K (just for the fun of it - it really is only Parodinal with potassium instead of sodium, of course). The formula is:

Water: 100 ml
Sodium sulfite: 40 g
Dissolve at roughly 50 degC (122 degF)

Water: 60 ml
Potassium hydroxide: 17.9 g
Dissolve the hydroxide, then add 15 g (30 capsules) of paracetamol while the hydroxide solution is still hot. Stir in the powder thoroughly and break any clots. It will turn reddish and murky, which is fine.

Once the two parts are cool, combine. Use the sulfite solution to wash out all the paracetamol solution. Make the final volume up to 200 ml (not 250!). Any undissolved sulfite can be added as crystals to the final container - it will dissolve over time. The brew is ready to use within two to three days. It is important that the cap of the bottle seals really tightly, as air leaks will eventually destroy the developing agent (4-aminophenol). Do not be alarmed if it turns redder everytime you open the bottle - that is natural, and it will still be active even if it looks like cola concentrate. The Parodinal formula of Zorkikat and others is short on the active ingredient by about 20%, if you compare it to other rodinal formulas. I believe that is the reason why it does not last long. My Panadonal-K lasts now for more than a year as a half-full bottle, without any signs of deterioration.

Hope it works for you.

Regards,
Jaco

Hi Jaco!

Thanks for that!

I have just got off the phone with a chemical company here in Cape Town.
I can get Potassium Hydroxide and Potassium Metabisulphite next week.
I had to enquire about the Potassium Sulphite at another company, who has not yet replied to my email.

If you ever want the Paracetamol powder I use, let me know and I can send you some!
It's cheaper than panado, and it's completely pure.



Parodinal Batch 27082012-01 and Parodinal Batch 27082012-02 have still not crystallised by this morning (30 Aug).
I'll use them on my test film later today or over the weekend!

Hi Martin,

Are you planning on ordering from BM Scientific? I got some of my chemicals from them, including enough KOH to share. You can also try Minema - they are generally cheaper and will have stock, but don't buy as yet. Rather PM me your postal address and I'll send you some KOH, as well as another surprise or two. My stocks are all in 500 g + quantities, and for things like developers that is usually more than one needs for a long time. Yes, for certain I would like some paracetamol, but I will trade you for it.

About Parodinal: I would advise against metabisulphite and/or carbonates as they affect the pH and you would then have to tweak your total balance to get things right, and it is not really necessary in the first place. You really only need three things: hydroxide, sulphite and paracetamol. If the hydroxide is potassium hydroxide, the solubility of sulphite is improved because of the "common ion effect", where fewer sodium ions compete to stay in solution. Potassium salts are as a general rule more soluble than sodium salts on a molar (and hence also mass) basis, and this is why if you use NaOH you will battle to get the sodium sulphite dissolved, but if you use KOH all eventually dissolves. You can use potassium sulphite with sodium hydroxide too, based on the correct molar (not mass) quantities. I'd be happy to do the calculations for you if you do not know how. Basically you divide the mass by the molar mass of the specified chemical, and multiply by the molar mass of the one you substitute. So for KOH substituting for NaOH the correction is 56.1/40.0 = 1.40. The same principle will apply to sulphite but the factor would be different (1.26) etc. I reverse-calculated the Panadonal-K formula against two other formulas - the pre-war Rodinal formula (which differs in containing EDTA and KBr) and the formula for Rodinal published in The Darkroom Cookbook. Those two formulas have the same 4-aminophenol content (within 1 %), and the Zorkikat formula is about 80 % of that. I think that is because ZorkiKat used only sodium chemistry and couldn't get everything into solution as is supposed to be the case. If you filter the Zorkikat formula, you will be in trouble, because the excess sulphite is necessary to protect the aminophenol from oxidation. The TDC and original formulas both employ potassium as well as sodium but in different ways. However, the end product has more or less the same composition in either case, and my adaptation matches that fairly well. The difference between various formulas lies in the byproduct which is usually derived from the way in which the aminophenol is introduced. In the case of TDC it is chloride, in the Parodinal formulas it is acetate, and in metonal it will be something like sulphate. I think at the concentrations after dilution 1:50 these byproducts do not affect the developing much, but I would appreciate if someone with more insight can comment. NaCl does affect some developers, but typically at higher concentrations than what one finds in Rodinal.

Regards,
Jaco

Hi Martin,

For metabisulphites (they are acidic) you have to do the following correction:

2KOH + K2S2O5 => 2K2SO3 + H2O

So if you use metabisulphite, part of your hydroxide is consumed to convert to sulphite, and you have to make a correction or the pH will not be correct. Hope that is clearer now than I stated above. Not in principle a problem, but the quantities have to be correct.

Jaco

dorff said:

Hi Martin,

Are you planning on ordering from BM Scientific? I got some of my chemicals from them, including enough KOH to share. You can also try Minema - they are generally cheaper and will have stock, but don't buy as yet. Rather PM me your postal address and I'll send you some KOH, as well as another surprise or two. My stocks are all in 500 g + quantities, and for things like developers that is usually more than one needs for a long time. Yes, for certain I would like some paracetamol, but I will trade you for it.

Click to expand...

Thank you. Theres a company just a few km away that can get me almost all I need. I have ordered 1kg of KOH from them. For technical grade KoH, it costs R23/kilo ex VAT. So no complaints. It'll ready for collection on Monday or Tuesday. I need to get more paracetamol and Sodium Sulphite next week as well. How much do you want of the paracetamol? Other surprises ?
Don't worry about the KOH, they are easily available here. I want to make some Parodinal for friends to try, so eventually I'll be making larger batches.

dorff said:

About Parodinal: I would advise against metabisulphite and/or carbonates as they affect the pH and you would then have to tweak your total balance to get things right, and it is not really necessary in the first place. You really only need three things: hydroxide, sulphite and paracetamol. If the hydroxide is potassium hydroxide, the solubility of sulphite is improved because of the "common ion effect", where fewer sodium ions compete to stay in solution. Potassium salts are as a general rule more soluble than sodium salts on a molar (and hence also mass) basis, and this is why if you use NaOH you will battle to get the sodium sulphite dissolved, but if you use KOH all eventually dissolves. You can use potassium sulphite with sodium hydroxide too, based on the correct molar (not mass) quantities. I'd be happy to do the calculations for you if you do not know how. Basically you divide the mass by the molar mass of the specified chemical, and multiply by the molar mass of the one you substitute. So for KOH substituting for NaOH the correction is 56.1/40.0 = 1.40. The same principle will apply to sulphite but the factor would be different (1.26) etc. I reverse-calculated the Panadonal-K formula against two other formulas - the pre-war Rodinal formula (which differs in containing EDTA and KBr) and the formula for Rodinal published in The Darkroom Cookbook. Those two formulas have the same 4-aminophenol content (within 1 %), and the Zorkikat formula is about 80 % of that. I think that is because ZorkiKat used only sodium chemistry and couldn't get everything into solution as is supposed to be the case. If you filter the Zorkikat formula, you will be in trouble, because the excess sulphite is necessary to protect the aminophenol from oxidation. The TDC and original formulas both employ potassium as well as sodium but in different ways. However, the end product has more or less the same composition in either case, and my adaptation matches that fairly well. The difference between various formulas lies in the byproduct which is usually derived from the way in which the aminophenol is introduced. In the case of TDC it is chloride, in the Parodinal formulas it is acetate, and in metonal it will be something like sulphate. I think at the concentrations after dilution 1:50 these byproducts do not affect the developing much, but I would appreciate if someone with more insight can comment. NaCl does affect some developers, but typically at higher concentrations than what one finds in Rodinal.

Regards,
Jaco

Click to expand...

Good to know that using KoH will help with solubility. Potassium Sulfite is impossible to find by comparison to Sodium Sulfite, which is also quite cheap.

Goodness! Thanks for all the insight. Invaluable!

With regards to the byproduct, how does your Panadonal-K results differ from Rodinal at 1:25?

Do you filter your solution or is it not necessary?

OK, Please excuse if this is wrong...

If I were to use Potassium Metabisulfite, would the following formula be correct?

28,1 gr Potassium Metabisulphite
14,2 + 17,9gr KOH
15gr Paracetamol powder
Water to make 200ml

I'm likely going to take your advice by using the KOH and Sodium Sulphite recipe, but since the Potassium Metabisulphite is so cheap, I'm likely to give it a try...just because I'm curious.

Do I need to get Kbr also? I can't find that on the current product lists I have.

Hi Martin,

Paracetamol: about 100 g I suppose (that will make 1.3 liters by quick calc)

Panadonal produces acetate instead of chloride. Paracetamol is a 4-aminophenol with an acetyl functional group attached - when that is removed by the hydroxide it produces an acetate. That reaction is slowish, and the reason why it has to ripen for two or three days. Glycin and metol are also related molecules, and I suspect they may also be transformed into Rodinal.

Don't filter, just put in everything and let it simmer. If any crystals form, it may be aminophenol in equilibrium with aminophenolate, which is part of the buffering necessary to preserve the developer. Let things settle, and use a dropper to extract the developer. If one uses capsules they form a fine muck that is probably binder, but using pure paracetamol that shouldn't happen, in theory at least.

You do not need KBr for this developer, I think initially it was added because without it the older film emulsions tend to fog heavily, just as our experience with RPX400. It may help if you add KBr specifically for such emulsions, but I haven't tested and don't know for sure. In that case, add it to the diluted developer, not to the concentrate. I have plenty of KBr, will send you some. It is used in Caffenol C-L too, so useful to have around, and I would say consider using it for stand development in general if you get streaky developing.

Will check your calcs tonight, and will PM you my calculation sheets.

Jaco

Fantastic, thank you.

I just got a quote from BMScientific. Their prices are very high.
R89/500gr Sodium Sulphite
R39/500gr KOH

The suppliers I use sell the Sodium Sulphite for R13/kg and the KOH for R23/kg. Anyways.

Looking forward to your PM.
I'll send you the paracetamol next week, when I have purchased more paracetamol and hopefully also have my own car back...

I developed a roll of film yesterday with monday's Parodinal batch 27082012-02 (The clear one)
At the time of opening, it was still clear, but more yellow in colour. After developing, the first crystals started appearing, and by this morning the colour is slightly pink-ish.

Here is another scan comparing it to the Rodinal R09 One-Shot I have:
The full res version is available for download HERE


With thanks to Jaco, I will be changing the formula and will be using KOH instead of NOH. Also, I will give a go at using a Potassium Metabisulphite based formula, just to feed my curiosity. I will continue with the scanned comparisons once those solutions are ready for use! Hopefully by monday I will have made these new batches!

dorff said:

Hi Martin,

Are you planning on ordering from BM Scientific? I got some of my chemicals from them, including enough KOH to share. You can also try Minema - they are generally cheaper and will have stock, but don't buy as yet. Rather PM me your postal address and I'll send you some KOH, as well as another surprise or two. My stocks are all in 500 g + quantities, and for things like developers that is usually more than one needs for a long time. Yes, for certain I would like some paracetamol, but I will trade you for it.

About Parodinal: I would advise against metabisulphite and/or carbonates as they affect the pH and you would then have to tweak your total balance to get things right, and it is not really necessary in the first place. You really only need three things: hydroxide, sulphite and paracetamol. If the hydroxide is potassium hydroxide, the solubility of sulphite is improved because of the "common ion effect", where fewer sodium ions compete to stay in solution. Potassium salts are as a general rule more soluble than sodium salts on a molar (and hence also mass) basis, and this is why if you use NaOH you will battle to get the sodium sulphite dissolved, but if you use KOH all eventually dissolves. You can use potassium sulphite with sodium hydroxide too, based on the correct molar (not mass) quantities. I'd be happy to do the calculations for you if you do not know how. Basically you divide the mass by the molar mass of the specified chemical, and multiply by the molar mass of the one you substitute. So for KOH substituting for NaOH the correction is 56.1/40.0 = 1.40. The same principle will apply to sulphite but the factor would be different (1.26) etc. I reverse-calculated the Panadonal-K formula against two other formulas - the pre-war Rodinal formula (which differs in containing EDTA and KBr) and the formula for Rodinal published in The Darkroom Cookbook. Those two formulas have the same 4-aminophenol content (within 1 %), and the Zorkikat formula is about 80 % of that. I think that is because ZorkiKat used only sodium chemistry and couldn't get everything into solution as is supposed to be the case. If you filter the Zorkikat formula, you will be in trouble, because the excess sulphite is necessary to protect the aminophenol from oxidation. The TDC and original formulas both employ potassium as well as sodium but in different ways. However, the end product has more or less the same composition in either case, and my adaptation matches that fairly well. The difference between various formulas lies in the byproduct which is usually derived from the way in which the aminophenol is introduced. In the case of TDC it is chloride, in the Parodinal formulas it is acetate, and in metonal it will be something like sulphate. I think at the concentrations after dilution 1:50 these byproducts do not affect the developing much, but I would appreciate if someone with more insight can comment. NaCl does affect some developers, but typically at higher concentrations than what one finds in Rodinal.

Regards,
Jaco

Click to expand...

My K-Parodinal mixed according to Jaco's instructions has cured and I shot a sheet today in strong [15 EV] sunlight. There is a large difference in shadow illumination at this time of the year and normally shooting anything at midday is problematic. I used exactly the same dilution and times for Rodinal. The K-Parodinal was slightly more contrasty with very similar shadow density. I metered with an incident meter as a single reading back towards the camera at 160 iso [Foma 200] I measured the negatives with my densitometer and the DR for both Rodinal and K-Parodinal sits at about 1.08 which is just right for a grade 2 print. 1.07 Rodinal 1.08 for K-Parodinal. The slight difference is irrelevant. I would say more due to me than the developers.

Is it the same as Rodinal? I have a test set up I use regularly and I ended up only shooting the one neg but have many Rodinal negatives to compare characteristics shot under the same light. I would have to say the mid and upper mid tones on the K-Parodinal neg are superior. Very smooth handling of highlights also. The blacks are clean and the whites clear and creamy. I think the K-Parodinal negs have the edge in sharpness and definition. Processed in a Jobo rotary system the sharpness and acutance is just wonderful. Most people are making the Parodinal with Sodium Hydroxide but considering I have enough Potassium Hydroxide to leave for any relatives I have I opted for KOH as that is also used for Rodinal.

Following exactly Jaco's instructions and dilutions based on the 200ml not 250ml final volume gave absolutely remarkable results.

My verdict -- K-Parodinal certainly takes the pain out of film development and I really feel it has enormous potential. I would certainly not loose sleep now if Rodinal suddenly disappeared.

Thanks, Steve. Good info I must also agree that Jaco's formula is working gloriously.

So, to get everything up to speed...

I've made a few batches of Jaco's formula, and am very pleased with the results. There has consequently been a lot of email correspondence since.

The current Parodinal family:


On the left (they yellow/amber colour solutions) are my early batches I made when I started this thread.
Batches 25082012-01 (the small bottle), and batches 27082012-01 and 02

In the middle, the two 250ml blue capped bottles, are batches I made with Jaco's recipe. Batches 03092012 and 07092012.
Batch 03092012 was made with 10% extra KOH, since the technical grade KOH had a minimum ASSAY of 89,5%.
After making this, Jaco assured me that the 10% compensation was too much, and that his recipe would have sufficient KOH required.
This lead me to make batch 07092012, which was made as instructed. I still haven't tested this batch
Of the two, I have only developed film with batch 03092012, which worked as advertised. (See comparison bellow)


The large bottle on the right is Batch 11092012, which was made with KOH + K2S2O5. This stuff needs to cure for two more days before I can test it.

All in all, I'm incredibly happy about the very clean and clear end product. So many thanks Jaco!

Some real world images instead of boring test shots: