Monday, July 9, 2012

Keeping Pyrogallol developers

The question of storage, and keeping an ascorbate-soda deveoper has been raised again and again.

From early on, the notion was that under no circumstance should or would a develioper like that keep in solution.

More so, from the beginning it was stated that a developer like Caffenol should be used within half an hour after being mixed.

Not only is this wrong - it has probably caused errors or opened for errors in the unnecessary rush so created.

Other posts in this blog will underline what I write here, we have used Caffenol over and our for up to 10 times from a mix, stored for weeks, employing certain tricks.

The current state of affairs and my position on this is that Caffenol can be used to develop 3 times as much as originally advised, like for instance 400 - 500 ml (you loose a little volume with every film developed) of developer can be used safely to develop 3 films, provided it is withing a short timespaan, laike say 48 hours....

This means that up until now most users have thrown out countless gallons and litres of perfectly good developer..

I cannot precisely pinpoint why this came to be, I'd just like to go back in time, before the more modern developing agents was in use, before Metol, Phenidone and Hydroquinone was used, back when "natural developers" was in use.

From early on the developing agents came from surprizing sources, like from leather industries where chemicals used for tanning leather also was found to act as developers.

The stuff used shared a lot of things in common with ascorbate and caffeic acid, and most of the time those developers also was soda-based, like Caffenol.

Not only did they share natural stuff with us, they also faced the same problems, their developer had to be fresh mixed, and steps where taken to keep them.

I'd like to publish a picture here, from a Kodak publication to give a hint on how this was done by one of the major players

Wednesday, April 25, 2012

SPUDSANOL, a potato developer!

I was making dinner for the boys the other day....
Traditional squarehead dinner, with boiled potatos, just like in the old days.
Most of the time we don't peel our potatos over here, we boil them unpeeled and serve them to be skinned at the table.

If you do it the other way around, save the peels and look at the end of this instalment.....

While standing there preparing food, it struck me: on a certain web-page they had a discussion on a lot of esoteric stuff as developing agents, among those sugar (don't believe that, off-hand......)

Potatos have a lot of stuff in them, mainly starchs, but the skin contains a lot of other stuff, just like fruits and berries (coffee for instance). So what is inside the water used to boil potatos?

Starch no doubt, but maybe other interesting stuff?

I saved the water it was semicloudy andlet is stand until cool.

Then I added 50 gram per litre of soda, disodium carbonate AKA washing soda.
Immediately the color changed, indicating that a chemiocal reaction took place, and micro bubbles covered the surface. I let it stand to subsidice, and measured pH, at pH 10.1
Thge color was now a light brown, totally transparent fluid, no bad smell at all.

I also noted that even if the air bubbles had gone, the surface was still covered by some mysterious stuff. It looked like SOAP. Apparently a reaction with fats or light wax in the solution had taken place, making a light soap (nothing wrong with soap in a developer boys!).

Into this I inserted a strip of fully exposed film, it blackened after 3 - 4 minutes. Developing action confirmed!

Spudswater with soda is a simple and cheap developer.............

I then added 15 gram per litre of ascorbic acid. There was effersescence, the light powder did float on bubbles and dissolved very quickly, AND ONCE MORE THE SOLUTION CHANGED COLOR.
The color was now a light light brown, and transparent.
pH was down from 10,1 to 9,2.

A strip of film inserted was blckened in half the time from the first test, I did this twice to ascertain my find. The strip blackened in 1,5 to 2 minutes.

maybe this could be tweaked a little more, for instance adding 35 gram Sodium sulfite per litre, or maybe a full battery of stuff like Trond does, but I prefer the simple alternative, with stuff that most people can find easily, so my tentative recipe will be:

Boil 6 to 8 potatos in a pot of water, save the potatos for dinner.

Save the water from and make sure the total volume is ca 1 litre.
Add 50 gram per litre of washing soda
add 15 gram per litre of ascorbic acid powder.

A restrainer to combat fog might be necessary, Postassium bromide is as always recommended.

I will test out this tomorrow with a testfilm (have to wait for light conditions tomorrow for the film)

I will start with development times a little less than caffenol, since the clip test indicated a little higher activity than Caffenol, but that might be wrong, time will tell.

So my time will be 12 minutes with Kodak Gold 100 C41 test film, with Ilford FP4 it will be 9 minutes.

Those that follow my blog or have read whats been written here before will note that the general principle here is the same as with my first experiment with LIPTONOL, a thea based developer, and later followed by Trond with BARKANOL :

Chemicals should never be extracted from (formerly) living tissue by Lye or strong organic solvents like alcoholn or Tri, this will most likely decompose the very stuff we're after and minimise activity in the finished mixture.

Use only boiling water, or if possible hot water like thea, and let it stand until cool. That should be plenty enough and has given us success so far.

This principle can be used for tests with a whole range stuff, bark from different trees, leaves, small twigs run in a blender, flowers, grass etc etc....

Now what if you peel your potatos? Save the peels from at least 8 potatos and boil them in ca 1 litre of water, use the water afyter separated from the peels, and use that as above.

Report and pictures to follow in a days time.
Since this is so easy and simple to try, give it a spin yoursel!

The raw mix with soda added, it turns purplish pH ca 10.1
The ascorbic acid added, pH ca 9.2

Clip tests came out ca 2 minutes, it will be interesting to compare this with Caffenol, Liptonol and Barkanol.....
Spudsanol has a certain RING to it, hope it succeeds!

PS I got a phone call, a question :

Do you boil your 'taters with salted water?
No I don't, first because table salt will not or to almost no degree penetrate potato skin so the salt is tossed out with the water = money down the drain. Second because salt would be a nhindrance to any developer, a restrainer where none is wanted, when testing for developing action, a restrainer is to be added only if needed.

First test, film now drying, and I have images.

I developed for 12 minutes with a C41 100 ISO film, against my better judgement, caffenol gets 16 minutes, I should have given it a little longer, like 18 minutes. Box speed thin, -1 extremely thin, depending on lightning (against the light, sidelighted, flat lightning etcetcetc)

Clearly underdeveloped, but we have developing action with water from boiling potatos, soda and ascorbic acid.

However, this does not necessary mean we have superadditivity, this might be a case of just two developing agents, and I would suggest another experiment :

Same water, soda and a little phenidone, maybe the stuff from potatos would work as an opposite to coffe, at this point I don't know..... First test now would be a simpe re-test but with 18 minutes dev. time, I know that would work.....
Posted 3 days ago. (permalink | edit | delete)

Sunday, April 22, 2012

Designing a developer part 4. Testing and evaluation.

Testing the developer.
Time has come to test the developer to see if it performs like it is supposed to.

To test this developer I shot a short strip of Kodak Imagelink HQ film in a Flexaret Va TLR camera with 35mm insert.

According to information on the net, the correct EI for this fil is about EI 25.
Set your meter to 25 ISO/ASA and your meter will tell you correct exposure.

I mixed the developer according to the formula with a small change.

10g Sodium Sulfite
0.25g Hydroquinone
0.35g Phenidone
4g Borax
1g Boric Acid.
0.01g Potassium Iodide.
1g Fotoplex-2 AKA Etidronic acid

 Since I had Dimezone-S at hand, I used this instead of Phenidone. Since it has a slightly higher mol weight and has a slightly slower working, I multiplied the amount of Phenidone by 1.4.
This is the accepted multiplier to use when using Dimezone-S instead Phenidone.

The measured pH was 8.6. This is a bit more than the design and calculation goal, pH 8.2.
I am investigating why is is a bit off the target, but initial hints are that the Fotoplex-2 doesn't inflict on the pH as much as the calculation shows.
This will be investigated further.

Anyway, the pH is lower than the pH where the hydroquinone is activated, so I went ahead and made a clip-test.
The exposed fil leader clip was blackend in 3 minutes.
This indicates a development time of about 12 minutes.
Well, I put the film into the tank and developed for 12 minutes@21c.
The difference between 20c and 21c is insignificant, but if you want to correct for it, just develop for 12:30 minutes.

Constant agitation for the first minute, then for 5 seconds each minute.
Water was used as stop bath. 3 tankfuls in one minute.

Normal fixing and drying.

The film came out quite well. Good deep blacks in the highlights and details in the shadows. Absolutely no fogging.

Sample images:
Imagelink HQ @EI25. Im my opinion, the contrast is a bit on the low side.
That may make it possible to shoot at EI50 and develop for  17 minutes.
This isn't tested, so if you do so, you are on your own.

Imagelink HQ @EI25. In my opinion, the contrast is a bit on the low side.
That may make it possible to shoot at EI50 and develop for  17 minutes.
This isn't tested, so if you do so, you are on your own.
This image also shows the downside of this film. It is easily scratched. This scratches is from the film transport in the camera.

 Triplet image shot with the Imagelink HQ film.
First one is according to meter, second is -1EV, third is +1EV.
In reality, the one shot at -1EV looks best, meaning that EI-50 is more correct for this film and development time.

 I also souped a PolyPan-F film exposed at EI-100 in the developer. This is a film with normal contrast, not a high contrast film like the Imagelink HQ or the Technical Pan.

It was developed for 15 minutes@21c. 
The result was just like expected. A bit low contrast indicating it may be developed for a slightly longer time. This will bring out more details in the shadows, enabling it to be shot at a even higher EI without blocking up the highlights in the developer.

Sample images:
Polypan-F at EI-100.
15 minutes@21c. 
The image has a bit low contrast.
The image is shot in bright sunlight.

Same image with increased contrast and a bit of unsharp mask to counter for the loss of sharpness in the scanning process. This image looks a bit better.

Another image that shows a bit low contrast.
The image is shot in bright sunlight.

Same image. Contrast adjusted a bit and some unsharp mask.

100% crop from another image on the PolyPan-F film.
Extremely fine grain.

Even if the pH is a bit higher than calculated, the developer works as planned.

The developing agents are calculated to be enough for more than 10 films, but I won't specify that you can develop more then 10 films in one liter of this developer.
Since Phenidone and it's derivative, the Dimezone-S is very little affected by bromide ions in the developer, the accumulated bromide in the developer will not slow down the activity much. In addition to this, selecting Potassium iodide as restrainer works against increased time because some of it is lost when developing a film, and some bromide is gained. 
The combination of Phenidone and Hydroquinone is also a factor. The Phenidone in this PQ developer is regenerated more effectively than Metol in a MQ developer by the Hydroquinone. This means that the level of Phenidone is fairly stable in the developer.
The net result is a fairly stable developer where almost no correction in development time is needed.

Because of that, I will not present a table of development times for each consecutive film.
Just use the same time and correct it only if the developer shows signs of slowing down.

Shelf life.
This is a PQ developer. PQ developers are a bit more stable than MQ developers like D76. You can expect this developer to last as long as a bottle of D76, if not longer.
Since it isn't an ascorbic developer, it can't suffer from the sudden death syndrome that seems to hit randomly at ascorbic developers.
It even contains a chelating agent to protect it from oxidation accelrated by metal particles from the water or impurities in the chemicals.
Stored correctly, this will last at least six months.
If you don't develop 10 films in six months, try to store it in a cool dark place. This will slow down oxidation.

The phenomena with pH being a bit higher than expected is under investigation.
It doesn't matter for this developer, but it is interesting to know why the calculation and pH meter shows different values.

Lets summarize the design goals:

  1. Low contrast developer for document films.
  2. Fine grain developer.
  3. Working solution, reuseable developer.
  4. Shelf life og more than three months.
The design goals seems to be met.
It is a low contrast developer suitable for document films.
It is a fine grain developer for said films.
It is a working solution developer. No need to mix anything when you need to develop a film.
It is reuseable for up to 10 films for a liter.
Shelf life should be no less than other PQ developers with sulfite as a preservative. It even contains an additional chemical to increase shelf life. There is no reason to belive this developer to have shorter shelf life than D76 or ID-11. They have a shelf life of six months or more.

It's a wrap!

Tuesday, April 17, 2012

Designing a developer part 3. Getting chemicals and mixing the developer.

Chemicals, where do we get them?

In order to mix this or another developer, we obviously need some chemicals.

We need the developing agents,  the sulfite, the alkali, the acid to adjust pH, the restainer and the chelating agent.

Many chemicals can be bought from specialists in photographic chemicals, but a lot can be found on e-bay.

Most photographic chemicals can be bought from Silverprint in the UK or Photographers' Formulary in the US. In addition to them, Fototechnik Suvatlar in Germany has a lot of chemicals in store.

Links to this companies at the bottom of this article.
BTW, Fototechnik Suvatlar is the only one that I have found that sells the Fotoplex-2 or Dequest 2010 in europe. He has the 60% solution in stock, not the 99% powder as I got.

Well, after buying a lot of white powder, and hopefully got it through the customs without being incorrectly arrested for importing drugs, we are ready to start mixing the developer.

Not quite! To mix this developer we need wery small amounts of some chemicals. We can't miss on this. Using twice the amount of specified, may result in a non working developer.
It's obvious that we need a precise scale.
If you haven't got one, buy one and don't continue until you have it in your hands.

They don't cost an arm or a leg, just a few dollars.

Try this search on e-bay:

e-bay search for 0-300g electronic scale

The first one:0-300g scale is good enough for our use.

Next you will need some small bottles. 100ml is good.
You will also need some methylated spirits or denaturated alcohol to dilute developing agents and restrainers in.

Start with mixing a 1% solution of phenidone in 100ml methylated spirits.
Dissolve 1g phenidone in 100ml methylated spirits. This is your 1% phenidone solution.
Label it as Phenidone 1%.

Mix a 1% solution of potassium iodide. Following the same procedure, dissolve 1g KI in 50ml methylated spirits and 50ml water. Label it as Potassium iodide, KI, 1%.

Mix a 1% solution of hydroquinone. Following the same procedure, dissolve 1g hydroquinone in 100ml methylated spirits.

Why do we mix it in alcohol?
Because it doesn't contain water to any degree, so there is almost no free oxygen to destroy our developing agents.

Why the water in the KI solution? because it's easier to dissolve that way, and it doesn't go bad anyway, so water here is ok.

At this moment we can start mixing the developer.

Mixing the developer.

Let's summarize what we have decided to use.

10g Sodium Sulfite
0.25g Hydroquinone
0.35g Phenidone
4g Borax
1g Boric Acid.
0.01g Potassium Iodide.
1g Fotoplex-2 AKA Etidronic acid

If your tap water is clean, without chemical additives and with a neutral pH, boil 1.5 liter of it and let it cool down to no more than 30c.

If your water is alkalic or contains large amounts of clorine or other additives, use distilled water.

Start with 700ml water in your 1L graduated beaker.
Add the 10 grams of Sodium Sulfite to the water and stir until it's completely dissolved.
Add the 4 grams of Borax decahydrate and stir until it's completely dissolved.
Add 1g Boric Acid and stir until it's completely dissolved.
Add 1 g Fotoplex-2 or Dequest 2010 if you have the powder version.
If you got the 60% solution from Suvatlar, use 1.67ml of it.
To measure small amounts like this, it's best to use a  small syringe. Use a 5ml or 10ml size.
Add 35ml of the 1% Phenidone solution.
Add 25ml of the 1% Hydroquinone solution.
Add 1ml of the 1% Potassium iodide solution.
Top up with water to 1000ml.

How did I come up with the number of milliliters for the different solutions?
Lets take the 1% KI solution. It contains 1 gram in 100ml.
Each ml contains 1/100 of the one gram, 0.01 gram.

Why not just use the scale to weigh out 0.01gram since it has 1/100 gram resolution?
Well, if the scale displays 0.01 gram, it may be 0.0051 gram or even 0.0149 gram. The scale will display the same. In addition to this we have something we call precision. It is possibly 1/100 gram plus minus one digit. Take that into concideration, and you may even have 0.0249 grams and the scale still displays
When you weigh out 1 gram, the error may still be the same, but instead of disrupting our precision completely, it is 2.5% at most.
When you take 1ml of the solution, you will get somewhere between 0.0098 gram and 0.0102 gram.
That's more than close enough.

Fill the 1000ml of developer in a glass bottle. It should store ok, but if you want to increase shelf life, fill some lighter gas in the bottle on top of the developer. This will displace any air so it won't oxidize our developer.

When it has cooled down to 20c it's ready to be tested.

Testing wil be delt with in the next posting.
I have to keep you on your toes you know. :-)

Where to buy chemicals:

Silverprint in the UK.

Photographer formulary in the US

Fototechnik Suvatlar, on the homepage for Moersch Photochemie in Germany
Click the link "Preisliste Rohchemie" for a PDF pricelist.

Keten Chemicals in Poland 


Friday, April 13, 2012

Designing a developer part 2. Alkali and restrainer

This time we are going to look at the accelrator, the alkali in the devloper, and the restrainer.

The accelrator.
Looking at our design goals, it specifies that we want to make a low contrast developer for using document films for pictorial purposes.

To get to this goal, we need to make sure that only the Phenidone part of the developer does any devloping job. The hydroquinone must not under any circumstance be activated. Hydroquinone produces way to high contrast for our design goal.

That means that we have to stay below pH 9 to make sure that doesn't happen.
Phenidone produces low contrast when the pH is low, so let's place the pH even lower on the scale. Let's place it at about the same level as XTol. That is pH 8.2.

What commonly available alkali is suitable for that? Not carbonate for sure. Neither Kodalk. Both are way to high in pH.
Borax may be suitable, but a 10% borax solution is pH 9.2 to 9.3.
How can we get from that level and down to 8.2?

Well, Sodium Sulfite will help, so will Boric Acid.

We want this develper to have some buffer capacity, but not too much since that will reduce the acutance.

Some Sodium Sulfite is required to preserve the developer, but too much will reduce sharpness. Since this is a developer for extremely fine grain films, we don't need to use large amounts of Sodium Sulfite to get the solvent action for reducing grain.

Let's use 10g Sodium Sulfite.
How much Borax?
Well, since we don't want a large buffering capacity, lets use a small amount, about 2 to 4g.
Let's start with 2g.
So far we have settled for this formula:

10g Sodium Sulfite
0.25g Hydroquinone
0.35g Phenidone
2g Borax

In addition to this, we introduce a chelating agent to keep metal ions from water and chemicals  out of the picture.  Metal ions increases oxidation rate and shortens shelf life.
Fotoplex-2 is very effective for chelating iron and other metal particles without disturbing the development process. It does shift the pH, so we need to introduce it on an early stage so that we don't have to recalculate all of it at a later stage.

To calculate the pH for this mix we need to know some data for the ingredients that may inflict on the pH.

This data looks like this:
Hydroquinone pka=10.35 mol=110.11g/mol
Sodium Sulfite pkb=6.81 mol=126.04274 g/mol
Borax (decahydrate) pkb=4.74 mol=381.37g/mol
Boric Acid pka1=9.237 pka2=12.74 pka3=13.8 mol=61.83g/mol
Fotoplex-2 pKa1=1.35  pKa2=2.87 pKa3=7.03  pKa4=11.3 mol=206,28g/mol

Phenidone doesn't inflict on the pH, so we don't need to include it in the calculation.

The dissosiation constants, pka and pkb is used to calculate how each chemical inflicts on the pH.
The mol weight is a measure of how much of this chemical is required to make a solution with with 1 mol of the chemical. By using this, we can calculate with a known relative amount of molecules in the solution.
A 1 mol Borax solutiuon contains the same amount of molecules as a 1 mol Boric Acid solution.
The pH solver needs this information to work.

To find the concentration in mol for each ingredient, we have to divide the amount of the ingredient with the mol weight for the ingredient.
Borax 2g= 2g/381.37g=0.005244 mol

So let's set up the required parameters for the solver.

Hydroquinone pka=10.35 c=0.002271
Borax pkb=4.76 c=0.005244
Sulfite pkb=6.81 c=0.07934
Fotoplex-2  pKa1=1.35 pKa2=2.87 pKa3=7.03 c=0.004848

The solver can't use more than 3 pKa values, but since the pH is in the area 7 - 9, the last value isn't used for the Fotoplex-2.

Entering this data into the solver results in the ansver pH= 8.0700

This is a bit lower than we wanted.
Let's increase the amount of Borax a bit to bring it up to the level we want.
Let's use 4g.

The parameters with 4g Borax is like this:
Hydroquinone pka=10.35 c=0.002271
Borax pkb=4.76 c=0.010488
Sulfite pkb=6.81 c=0.07934
Fotoplex-2  pKa1=1.35 pKa2=2.87 pKa3=7.03 c=0.004848
This results in pH=8.3555

This is a bit more than wanted, but since we want some buffering capacity, let's introduce some Boric Acid to bring the pH a bit down and increase the buffering capacity.

Let's use 1g Boric Acid.

The parameters with 1g Borc acid added looks like this:
Hydroquinone pka=10.35 c=0.002271
Borax pkb=4.76 c=0.010488
Boric_Acid  pka1=9.237 pka2=12.74 pka3=13.8 c=0.01617
Sulfite pkb=6.81 c=0.07934
Fotoplex-2  pKa1=1.35 pKa2=2.87 pKa3=7.03 c=0.004848

Entered into the solver it looks like this:

The answer looks like this:

The pH is 8.253750. In reality, we don't use more than 2 decimals anyway, so pH is 8.25
This is what we wanted, so let's settle for the formula that looks like this:

10g Sodium Sulfite
0.25g Hydroquinone
0.35g Phenidone
4g Borax
1g Boric Acid.
1g Fotoplex-2 AKA Etidronic acid

We can leave out the Fotoplex-2 if we want, but the pH will be higher.
To counter this, you have to increase the amount of Boric Acid to 8-10g

I don't reccommend this as this increases the buffering capacity and by this reduces the sharpness of the developer. If you don't increase the amount of Boric Acid, the pH will be about 9.1 and you are in the vincinity of the pH where the Hydroquinone gets activated and the contrast will be too high.

The restrainer.
Almost every developer needs a restrainer to prevent buildup of fog.
Common restrainers are Potassium Bromide, KBr and Benzotriazole, BZT.
A less common restrainer is Potassium Iodide, KI.

BZT doesn't work very well at this low pH level, so we can rule this out.
KBr works well, but in a developer intended for re-use, the amount of Bromide in the developer will increase when the developer is used. This will increase the development time from film to film.
This is not an ideal situation.
Selecting KI as restrainer has a positive side-effect. It is less soluble in water, so when used in a developer, part of it will still be in the film emulsion when we pour out the developer. Because of this, the amount of KI will decrease for each film developed. At the same time, the amount of Bromide will increase. This counters the effect of loosing some KI for each film developed.
The net sum of the effect of the restrainers will be more or less the same for the first and the film developed. There will be some difference, but less than with just using KBr as a restrainer.

The amount of KI needed is about 1/100 of the amount of KBr to get the same effect.
Instead of using 1g KBr, let's use 0.01g KI.

The complete formula is like this:
750ml Water
10g Sodium Sulfite
0.25g Hydroquinone
0.35g Phenidone
4g Borax
1g Boric Acid.
1g Fotoplex-2 AKA Etidronic acid
0.01g Potassium Iodide.
Water to 1000ml.

Since this isn't tested yet, I can't be sure it will work, but in theory it will.

Next posting will contain practical information of mixing the developer and possibly first tests.


Data about chemicals may be found on the net. Just do a search. You will find both PKa, PKb and mol weight for chemicals.

Wednesday, April 11, 2012

Designing a developer. Part one.

When you are going to design a developer, you have some work to do.

First you have to define your goals.
  • Is it going to be a fine grain developer?
  • Is it going to have high accutance?
  • Is it going to give normal, high or low contrast?
  • It it going to be one-shot, or reuseable?
  • Is it going to have long shelf life?
  • It is going to be mixed as a concentrate?

All this questions must be answered before you start the design process.

Well, this time I am going to design a low contrast developer giving reasonable contrast and reasonable fine grain. It is supposed to be used for developing fine grain, high contrast document films.

I want the developer to be reuseable, and is will be mixed as a working solution. A shelf life of three months is enough for my use.

To meet this goals I have to make some choices.
First, what developing agent or agents to use.

Obvious choices are Metol or Phenidone.
Both makes a soft working and fine grain developer alone at low pH.

Both suffer from rapid oxidation without any chemical to protect them.
Adding Sodium Sulfite to a Metol developer will protect the Metol, but will also increase the acivity of the developer so the contrast may build to quick.

Phenidone will oxidize quickly even with some Sodium Sulfite present, but adding a minute amount og Hydroquinone will protect it quite well without increasing the contrast too much.

That leaves us with another problem. How do we keep the pH low enough that the Hydroquinone doesn't get activated as a developer?

Selecting the correct alkali will take care of that.
The buffering action of the alkali mustn't be to good, because this will reduce the acutance or sharpness.

So let's settle for Phenidone as the developing agent and a small amount of Sodium Sulfite and Hydroquinone  to protect it from going bad.

 The Hydroquinoine gets activated at a pH above 9 somewhere, so we want to keep the pH below that.

How much Phenidone do we need?
Let's settle for a reuseable developer where we want to be able to develop 10 films in one liter.
Developing one film requires about 0.016g Phenidone.
If we don't take the regeneration of Phenidone by the Hydroquinone into concideration, we will need 0.16g Phenidone in our liter of developer.
That's about 1/10 of the amount in the POTA developer.
This is the minimum amount. To have some headroom and avoid total exhaustion, let's double that amount to 0.3g Phenidone.
Since the Hydroquinone regenerates the used Phenidone, this may be enough for our task.
How much Hydroquinone do we need?
Since it only are used to regenerate the Phenidone, we don't really need much. 0.25g may be enough for the task.
We have to regenerate 0.016g Phenidone or 0.0000986 mol Phenidone per film. That isn't very much!
Let's see how much Hydoquinone that is if we accept that we need one molecule Hydroquinone to regenerate one Phenidone molecule.
We need the same amount of molecues, 0.0000986 mol Hydoquinone. That is 0.0108g Hydroquinone per film, or 0.11g Hydroquinone per liter developer.
So 0.25g HQ is more than enough.

To protect this from oxidation we need some Sodium Sulfite.
How much? 10g is enough for this task.

So far we have arrived at this formula.
Sodium Sulfite 10g
Hydroquinone  0.25g
Phenidone        0.3g

What do we need in addition to this?

Well, we need some kind of alkali as an accelrator and a restrainer to avoid fog.

This will be discussed in the next postings.

Friday, March 23, 2012

Taking PC-glycol one step further.

The basic PC-glycol developer is easy to mix.
70ml glycol.
12.5g sodium ascorbate
0.25g phenidone.
Top up with glycol to 100ml.

I used concentrated engine coolant. This is ethylene glycol with a few additions
that doesn't inflict on the workings of the developer.
This concentrate has a shelf life of several years.
This concentrate is to be used in a 1:50 dilution.
Make a liter of water containing 5g washing soda or 1.7g of sodium hydroxide and 6.1g of borax.
This is part B.

For a 300ml tankful take 6ml of the concentrate and 294ml of part B.
For a 500ml tankful take 10ml of the concentrate and 490ml of part B.
Starttime is 8 minutes for 100 ISO B&W film.

This is a bit awkward. It is easier to just dilute with water.
Reading about borax and why borax is used in antifreeze,
I started to wonder if it is possible to add borax to the PC-Glycol solution.
Well, it is. Ethylene glycol can dissolve more than 40% borax at 25c.
It can also dissolve a small amount of sodium hydroxide.  That lead me
to this recipe.

Glycol 70 ml (Ethylene glycol in the form of concentrated engine coolant)
Sodium ascorbate 12,5 g = about 10g ascorbic acid.
Phenidone 0,35 g
Borax 20 g
NaOH 4 g

Top up with glycol to 100ml.

Heating the glycol a bit made it possible to dissolve the ingredients.

Use concentrated anti-freeze for car engines.
Use the blue ethylene glycol stuff. Not the "green" or non-toxic or low-toxic versions. Do not use the red long-life version either. The blue old-fashioned concentrated ethylene glycol works ok. You can use the cheapest you can find. They contain less "snake oil".

Diluting 1:20 with water gives a developement time of 6.5 minutes
for ISO 100 B&W film.
pH is 10.9 in the working solution.
Diluting 1:50 with water gives a develoopment time of 8 minutes
for ISO 100 B&W film

pH is just below 10.9

It is possible to add sodium sulfite to the developer when diluting.
Use 60-100g/L for a solvent action.

Sample images:
 Shanghai GP-3@100 ISO
 Shanghai GP-3@100 ISO

Tuesday, March 20, 2012

Creating a XTOL clone.

I have been reading about XTOL and the clones with names like MyTol and Instant MyTol.
The concept is interesting, but none of them except XTOL has any substantial shelf life.

There is some recipes that specifies mixing a concentrate in TEA, but TEA isn't available over here, so we have to either make a concentrated developer in ethylene glycol AKA concentrated engine coolant, or just mix the working solution in a bottle.

I have tried with ethylene glycol engine coolant and it works great, besides that sodium sulfite can't be dissolved in EG.

This time I choose to mix in clean water.
The goal is a developer that performs close to XTOL.

Mix as this:

Water 700ml
Sodium sulfite 75g
Ascorbic acid 12g
Dimezone-S 0.3g
Borax 25g
Boric acid 12,5g
Fotoplex-2 1g AKA Fotoplex-2 or Dequest 2010
Kbr 0.1g
Benzotriazole 0.03g
Water to 1000ml

The resulting pH should be 8.2

This recipe contains Dimezone-S instead of Phenidone. I have to use 1.4 x the phenidone amount to get the same activity. 0.3g Dimezone is about the same as 0.21g Phenidone.
The rationale for using a bit more Phenidone/Dimezone-S than the MyTol recipe is that developing one roll of film uses up about 0.015g phenidone. I want to have the possibillity to develop more than 10 films in one liter of developer without running into exhaustion problems.
I also use a bit more sulfite than MyTol. This to push it into the solvent developer segment. It also helps keeping the grain fine.
Benzotriazole is added to keep fogging on old outdated films to a minimum level.
If fog still is s problem, the amount may be increased to 0.05g, but not more without loosing film speed.
Using benzotriazole reduces the need for KBr, but including 0.1g helps the contrast a bit and helps avoiding bromide drag.
Etidronic acid, 1-Hydroxyethylidene-1,1-diphosphonic acid, CAS.Nr. 2809-21-4 AKA Fotoplex-2 or Dequest 2010 is added to avoid the XTOL sudden death syndrome.
According to experts, this is THE ingredient to stop the sudden death of ascorbic developers.

Tests so far shows an activity level on par with D76.

Shanghai GP-3 needs 8.5 minutes @22c, Agfa APX-100 needs 8 minutes @22c.
100 ISO B&W films like Fomapan 100 needs about 6 minutes@22c
Use as D76. Either reuse and add 6% time for each film or dilute 1+1 to 1+3 and use as one-shot.

Sample images.

 Shanghai GP-3 @100 ISO. 8.5 minutes @22c. No adjustments other than rescaling to smaller size.

100% crop from previous image. The image is scanned at 4800DPI.
There is hardly any grain visible. No adjustments, no sharpening.

Agfa APX 100. 8 min @22c. Contrast increased a tad due to overcast weather and very flat light that day.

Tuesday, February 21, 2012

Kodak imagelink HQ in the Lomad developer.

Kodak imagelink HQ is a high contrast micro-film made for automatically photographing checks and other documents in dedicated photo machines.

It is available from sellers on e-bay from time to time at a reasonable or not so reasonable price.

It has some drawbacks. High contrast and low speed two of them.
In addition it isn't perforated and it is easily scratched in the camera or in handling.
It is also very stiff and difficult to handle. It has to be taped to the takeup spool to make it work.

To use this film you have to use a camera that can use unperforated film. Some 35mm cameras and some 35mm kits for TLRs have this possibillity.

Well, what is positive about this seemingly hopeless film?
Two things:
1: Extremely sharp.
2: Extremely fine grain.

I received 10 meters of this film to experiment with a couple days ago.
Since I have a Flexaret Va with a 35mm kit, I had to test it. This camera have no sprocket wheel for film perforation, so it can use unperforated film without any modifications.

I loaded up a cassette with film and loaded the camera with it. I had to tape the film to the takeup spool to stop it from slipping out of the spool when tightening the film.
This was just as expected.

I shot the film at ISO 25 as indicated by others that had tested this kind of film.

To develop the film I selected  my LOMAD developer.
Since this is a two-bath developer with some compensating qualities this will do the job.
I developed for 5+6 minutes@22c.

The results are good. A bit high contrast, but with a long grayscale. Adjusting the scanner software to this kind of image gave me quite nice images.

To be sure to make the job for the developer as difficult as possible I shot some test images in bright sunlight on snow with objects in the sun and in the shadows.

Sample images.
Ine of the neighboring houses. The house is in the shadows, but the clouds in the sky are in bright sunlight.

My snowblower. Yes, we have plenty of snow! Note the details in the shadows in the bucket and the details in the sun-lit snow.

A 100% crop from the previous image. The limiting factor for sharpness is the lens in the camera.