Progress on XTOL-concentrate

[albada]

As I mentioned last week, I'm trying variations of a baseline developer. Here are six developers I recently tested:

Sodium sulfite ............... 35, 40, 45, 47.5, 50, 55 g
Sodium metaborate ...... 2.4, 2.2, 2.0, 1.9, 1.8, 1.6 g
Ascorbic acid ................ 4.5 g
Phenidone .................... 0.05 g
Propylene glycol ........... 15.5 ml (includes %-solution for Phenidone)
pH = 8.02 for all of these.
​

All were developed to the same contrast (slope) as stock XTOL for TMY2.

The experiment was to see what effect various levels of sulfite had, keeping pH constant. I'll identify each developer by its sulfite content (e.g., "the 40 developer").
The grain looks identical for the 40 through 55 developers, and is a hint better than XTOL. Grain is a hint coarser than XTOL for the 35 developer. The lower sulfite developers might be a tad sharper than the highest sulfite developers.

The dev-times were: 15.3, 14.25, 14.1, 14.0, 13.83, 13.58 minutes. Here's a graph of those dev-times:



The pH is constant, so the time-differences are solely due to the synergistic effect of sulfite on the developer. Notice that dev-time shoots up when sulfite drops below 40.

Here's the most interesting graph. This shows loss of true speed (Y-axis) versus sulfite-content (X-axis):



For each developer, I calculated the difference in EI (i.e., effective film-speed) using speed-points determined by densities of .1 above B+F and .2 above B+F, and calculated the loss of speed compared with XTOL. I averaged the number-pairs to help smooth the results, resulting in this chart.

Yes, XTOL is always faster than these developers, I suspect because it uses DimezoneS instead of Phenidone. But the loss is insignificant up to 45 -- only 0.08 stops of speed lost; that's only 1/12th of a stop. But above 45, the loss shoots up. So adding sulfite over 45 reduces true speed and gains nothing that I can see.

Evaluating trade-offs: There's no advantage in going above 45; all that does is reduce speed and possibly sharpness. And 35 gives worse grain with an insignificant speed-boost (and longer dev-time). That leaves 40 and 45. Suppose the user of this developer is not accurate in measuring sulfite. Then selecting 40 means risking thin neg's if too little sulfite is supplied. OTOH, 45 is more tolerant of too little, but risks a small speed-loss if too much sulfite is supplied. However, in this case the higher pH will partly compensate by increasing density. So the risk of disappointment is lower with 45 than 40. So I think 45 wins. That happens to be the baseline developer I described here: (there was a url link here which no longer exists).

Any comments about all this?

I'm thinking of boosting metaborate to boost pH and see what happens. The low pH of 8.0 concerns me because DS-10 had trouble with some slow films, and its pH was 8.0, which might be the cause. The amount of ascorbic acid seems a little high, as the ascorbic/phenidone ratio is 90. Gainer's graph leveled off at 80. That suggests either decreasing my ascorbic acid or increasing the phenidone. Any suggestions about other variations to try?

Mark Overton

 

[Rudeofus]

Mark,

first let me express my amazement and my gratitude that you go through all this effort and document not only the final results but also all these important intermediate steps which got you there. There are two variations to this experiment which would interest me personally and which might be of interest to others:

• Effect of using Borax instead of Metaborate. The latter one is more difficult to get and with a pH of around 8 Borax should be more than alkaline enough to work. It will take a tad more Borax than Metaborate which means we will get better buffering, which in turn means possibly reduced sharpness. Since we turn a lot of wheels here when changing from Metaborate to Borax, a practical experiment could be most helpful.
• Effect of PG on dev performance. Quite often I see stock developer recipes (think Pyrocat HD, PC-TEA, ...) but need only one or two rolls of film processed, so I'd like to skip the solvent for the concentrate. This would be poor advice with TEA, of course, but what about PG? PG is neither a silver solvent nor an alkali, so leaving it out should have less effect, but from what I read it does interact with the Metaborate. A quick experiment could shed some light on this.

PS: There are a few tricks which could reduce the cost of dev capacity testing: If you use fully exposed test rolls instead of step wedges, you put a lot more strain on the dev, since more silver halide gets reduced. Second, from what I read, T-grain films have less silver than traditional films, so traditional films might again need more dev than TMY2. For testing dev capacity, I'd go with the cheapest traditional 400 speed film you can find.

PPS: Since you design a dev here for very casual home developers, I'm not sure whether we need to squeeze the last penny out of its raw materials. One might as well err a bit on the high side without much financial effect.

 

[albada]

Rudi,

Thanks for the kind posting. I'm glad not everybody is bored with this detailed engineering-work.

I think Borax would work fine. My reluctance in using is (1) it carries much water with it (10H2O IIRC), which would need to be steamed out of the concentrate, and (2) a greater quantity would be required to raise pH to the desired level, requiring that more concentrate be used per litre. I know it's difficult for relayer to find in Ukraine, but can't Europeans buy metaborate easily from the UK and Germany? For mixing directly into water, Borax dissolves slowly. So if metaborate is unavailable, I'd suggest trying TEA instead of Borax.

PG reduces pH slightly and slows development a bit. It can be omitted from direct-to-water brews by reducing development-time slightly.

Good point about T-grain films containing less silver. I'll do my capacity-tests using the brick of Tri-X I have in the freezer.

Mark Overton

Mark,

first let me express my amazement and my gratitude that you go through all this effort and document not only the final results but also all these important intermediate steps which got you there. There are two variations to this experiment which would interest me personally and which might be of interest to others:

• Effect of using Borax instead of Metaborate. The latter one is more difficult to get and with a pH of around 8 Borax should be more than alkaline enough to work. It will take a tad more Borax than Metaborate which means we will get better buffering, which in turn means possibly reduced sharpness. Since we turn a lot of wheels here when changing from Metaborate to Borax, a practical experiment could be most helpful.
• Effect of PG on dev performance. Quite often I see stock developer recipes (think Pyrocat HD, PC-TEA, ...) but need only one or two rolls of film processed, so I'd like to skip the solvent for the concentrate. This would be poor advice with TEA, of course, but what about PG? PG is neither a silver solvent nor an alkali, so leaving it out should have less effect, but from what I read it does interact with the Metaborate. A quick experiment could shed some light on this.

PS: There are a few tricks which could reduce the cost of dev capacity testing: If you use fully exposed test rolls instead of step wedges, you put a lot more strain on the dev, since more silver halide gets reduced. Second, from what I read, T-grain films have less silver than traditional films, so traditional films might again need more dev than TMY2. For testing dev capacity, I'd go with the cheapest traditional 400 speed film you can find.

PPS: Since you design a dev here for very casual home developers, I'm not sure whether we need to squeeze the last penny out of its raw materials. One might as well err a bit on the high side without much financial effect.

 

[albada]

I got thinking more about the speed-loss graph, and realized that it might be more widely applicable if the X-axis were changed to the ratio of sulfite to Phenidone. Here's the modified graph:



When the sulfite/Phenidone ratio is over 900, the speed-loss shoots up. When it's below 800, grain gets worse. So the range 800-900 is ideal. But is this true of other developers? XTOL was carefully designed, and I've found that .105 g of Phenidone substitutes for .2 g of DimezoneS. So XTOL's sulfite/Phenidone ratio would be 88/.105 = 838, which is in the ideal zone.

Note that speed (EI) increases as you go left on the graph. What happens if you decrease the sulfite/Phenidone ratio to around 200? I tried that in January by semi-accident, and got a developer that yields high speed and more grain. If you develop with it to a low contrast (i.e., under develop), you get normal shadow-detail (i.e., box speed) and wide dynamic range for high contrast scenes. Rudeofus: This is the low contrast dev you used a few months ago.

Anyway, this is something for designers of PC-type developers to be aware of.

Mark Overton

 

[albada]

Here's a question for chemists:

Does alkalinity or acidity affect the propensity of a non-aqueous (PG-based) concentrate to crystallize?

I've seen two kinds of crystallization: (1) the white kind described in earlier postings, where the concentrate separates into a white cream and the PG solvent, and (2) some clear cubical crystals growing on the bottom and low-sides of the bottle (not precipitate). DimezoneS in PG, or very high concentrations have caused (1). A fairly high concentration-ratio of 0.46 caused (2) in one bottle. BTW, I define "concentration-ratio" as WeightOfPowdersInGrams/VolumeOfConcentrateInMl. Now, the bottles that have crystallized have also been rather alkaline (giving higher pH when mixed with water), whereas the stable ones have lower pH. So I'm wondering if high pH makes a concentrate more prone to crystallization.

TIA for any clues about this.

Mark Overton

 

[Photo Engineer]

Mark;

There are many crystal habits from cubes to octahedra to needles to plates and etc. Each chemical has a typical crystal habit which is partly based on the solvent from which it precipitates. The pH is not directly related to crystal formation. Crystal formation is related more to the concentration of all of the materials present.

PE

 

[albada]

Mark; There are many crystal habits from cubes to octahedra to needles to plates and etc. Each chemical has a typical crystal habit which is partly based on the solvent from which it precipitates. The pH is not directly related to crystal formation. Crystal formation is related more to the concentration of all of the materials present. PE

Ron, thanks as always for the help! It looks like I'd better keep those concentration-ratios down.

Also, I haven't forgotten DimezoneS. My tests show that, compared with Phenidone, it gives slightly higher speed (EI) and lower fog, with the same grain. I'd like to take your suggestion from many months ago and use TEA instead of metaborate in the DimezoneS-based formula that crystallized. The resulting formula will be similar to the organic solvent version of Instant Mytol (Jordan Wosnick). I plan on doing this work after finishing the Phenidone formula described in recent postings. Plus I want to work on a low contrast developer. Plus C-41 developers. There are too many things I want to do! This hobby is making retirement sound good.

Mark Overton

 

[Gerald C Koch]

I think Borax would work fine. My reluctance in using is (1) it carries much water with it (10H2O IIRC),

Anhydrous borax is available commercially. You could also make your own.

 

[albada]

Anhydrous borax is available commercially. You could also make your own.

I didn't know an anhydrous form was available. Thanks for pointing that out. And a bit of searching showed that making it myself means heating Borax to near the melting point of steel. Wow! Or would heating it in an oven actually drive out all the water? There's a long posting near the bottom of this page that's interesting: http://www.bladeforums.com/forums/showthread.php/202717-anhydrous-borax

Yet more questions...

Regarding crystallization: Does temperature affect the rate of growth of crystals? I would expect higher temp to increase the rate, but higher temp also boosts solubility, which might hinder crystal-growth. I'd like to do an accelerated test for crystallization, and was wondering if keeping the bottle hot would help or hurt.

Regarding TEA: I know that TEA is a solvent for silver halide, but how does it compare with sodium sulfite? 1 ml of TEA has the solvent-effect of how many grams of sulfite? When I add X ml of TEA, I'm wondering how many grams of sulfite to reduce to keep the same net solvent-effect. (I know sulfite does other things too, so it's all trade-offs).

TIA,

Mark

 

[Photo Engineer]

Mark;

Temperature has a profound effect on crystallization with the rate generally going up as temperature goes down.

TEA, AFAIK, is much less of a silver halide solvent than Sulfite.

PE

 

[Kirk Keyes]

Great find on the pH meter! That should give much better results than your old one. Keep looking for a temp probe. It may be cheaper to get a second electrode with a built in temp sensor than buying the sensor outright.

 

[Gerald C Koch]

I didn't know an anhydrous form was available. Thanks for pointing that out. And a bit of searching showed that making it myself means heating Borax to near the melting point of steel. Wow! Or would heating it in an oven actually drive out all the water?

In a pinch you can prepare small quantities of anhydrous borax with the help of a Meker burner. The borax must be fused to drive off all the water. A Meker burner produces a flame of 1500oC which is hotter than a Bunsen burner can produce. But fortunately this form of borax is cheap.

 

[Kirk Keyes]

Jerry - what do you fuse the borax in? And then how do your get it out??

I'm guessing that you'll need a ceramic crucible. And from making borax beads in Qualitative Chemistry class, then when the fused borax cools, it's going to make a rather hard block in the bottom of the crucible. And hard to get out without breaking the crucible...

I used to analyze plant matter for fluoride (they were testing down-wind from an aluminum refining plant) by dissolving it in sodium hydroxide using zirconium crucibles. (You could not use ceramic as the glazing on the ceramic dissolved, and you could not use a platinum crucible as the platinum would dissolve - a rather expensive mistake if one tried it!!) The hydroxide would set up so hard in the crucible that you could not chip it out without it flying all over the place, causing you to ruin the sample, so I came up with the trick of swirling the hot, molten hydroxide around until it chilled and set to the sides of the crucible. Then when fully cool, I could toss them in a beaker and rinse them with dilute HCl until the hydroxide dissolved. You can't do that when you're trying to make anhydrous borax...

 

[albada]

Great find on the pH meter! That should give much better results than your old one. Keep looking for a temp probe. It may be cheaper to get a second electrode with a built in temp sensor than buying the sensor outright.

Yes, that thing is going to spoil me. But I figured out a trick for getting a temperature into the meter: apply a resistance to the ATC connector using a potentiometer. That way one can simply dial-in the temp seen on the thermometer. This evening, I tried various resistors and got a table of corresponding temperatures from the meter, so now I know what kind of resistor-network to solder together. That's another electronic hack until I find a temp probe (and I like your idea of an electrode with built-in temp sensor).

I also brewed another concentrate this evening. Tests done by Alan Johnson and myself show that a concentration-ratio of 0.34 is stable. A recent concentrate at 0.46 is crystallizing a little. So I just mixed one halfway between them, at 0.40. Here's hoping...

Mark Overton

 

[Rudeofus]

by dissolving it in sodium hydroxide using zirconium crucibles.
[...]
so I came up with the trick of swirling the hot, molten hydroxide around until it chilled and set to the sides of the crucible. Then when fully cool, I could toss them in a beaker and rinse them with dilute HCl until the hydroxide dissolved.

I was not aware of the difficulties in dissolving NaOH ... or did I miss something ?

 

[Photo Engineer]

Kork said noting about NaOH being difficult to dissolve. He was describing a lab technique that allowed one to prevent formation of big chunks of NaOH. Instead, by swirling, he formed a thin film of NaOH.

PE

 

[Gerald C Koch]

Jerry - what do you fuse the borax in? And then how do your get it out??

I would not allow the borax to cool in the crucible but rather pour it out immediately after the fusion. I would use the unglazed side of a tile. The solid will have to be ground up in a mortar. However as I said before it's easier just to buy the stuff. Years ago on a weekend when everything was closed I had to make some anhydrous sodium metaborate by fusing borax and sodium hydroxide.

 

[Alan Johnson]

After more experimenting, I've come up with the formula below. Its grain is slightly better than XTOL, sharpness is the same, and dev-times are longer. The 1-litre formula for mixing directly into water:

Sodium sulfite ................. 45 g
Sodium metaborate ........ 2 g
Ascorbic acid .................. 4.5 g
Phenidone ...................... 0.05 g
Target pH = 8.05 to 8.10.
13:40 minutes for TMY2.
​

For a concentrate, mix everything except sulfite into 16 ml of propylene glycol.

Mark Overton

A plastic Tablespoon was dipped into sodium sulfite,wiped off level with a card.Consecutive weights (grams) were:
25.3,23.5,23.5,23.7,23.3,24.5,24.3,24.3,23.6,24.0; Average=24.0g
I daresay 2 level plastic Tablespoons of sodium sulfite would be OK for this formula.
I am in favor of spoons because I remember Crawley's FX-55 developer, great developer, nobody AFAIK uses it because it calls for ingredients to be weighed out each time to make the working solution.
As there is no international spoon users would need to calibrate their spoon first.
And remember to use the multiplying factor if use 8-mol sodium metaborate,the formula above is for 4-mol.

 

[Photo Engineer]

Alan;

Back to the old argument. Well, tablespoons vary a bit in the US, and chemicals vary in crystal habit from batch to batch and even in one batch. I have found a variation of greater than 20% just due to crystal habit. This is often not accurate enough. It depends on the effect of the chemical in question.

PE

 

[albada]

Alan's posting made me think again about how to measure. Teaspoons and tablespoons make it easy.
What do folks think of this idea?:

The problem is: To make some one-shot developer, you need to measure some sulfite powder and concentrate liquid.
My idea is to use plastic medicine cups, like these:
http://www.amazon.com/`Medicine-Cup...7561939&sr=8-5&keywords=plastic+medicine+cups
That low price is for a package of 100, so the individual cups cost almost nothing.

Step 0: Before measuring anything, you draw two horizontal lines at the correct fill-levels on a cup using a black felt-tip marker. You only need to do this once, and the black lines make it easy to see the fill-levels.

Step 1: Measure the sulfite powder, tapping the side of the cup to flatten the surface of the powder (and to compact it).
Step 2: Pour into the empty beaker.
Step 3: Measure the concentrate liquid.
Step 4: Place the medicine cup in the beaker (on the powder).
Step 5: Add the correct amount of water to the beaker.
Step 6: Stir until the powder is dissolved, and remove the cup from the beaker.

The advantage of this approach is it can handle any quantities, such as 225 ml for 35mm SS tanks, or 550 ml for 120-film in Paterson, or anything else. But are the above steps too much of a hassle?

Mark Overton

A plastic Tablespoon was dipped into sodium sulfite,wiped off level with a card.Consecutive weights (grams) were:
25.3,23.5,23.5,23.7,23.3,24.5,24.3,24.3,23.6,24.0; Average=24.0g
I daresay 2 level plastic Tablespoons of sodium sulfite would be OK for this formula.
I am in favor of spoons because I remember Crawley's FX-55 developer, great developer, nobody AFAIK uses it because it calls for ingredients to be weighed out each time to make the working solution.
As there is no international spoon users would need to calibrate their spoon first.
And remember to use the multiplying factor if use 8-mol sodium metaborate,the formula above is for 4-mol.

 

[Cor]

Just today I came across above thread, I do not stop by APUG that often. Cannot pretend to have it read completely nor understand everything, but it is truly a heroic and determined effort Mark !

I am test driving InstantMytol now for about 6 months, and have been very satisfied with it, so I wonder why you did not give that formula a try (or perhaps you did).

Just FYI I'll post my procedure below, but really Jordan Wosnick should be credited for this developer !

Best,

Cor

InstantMYTOL

Stock solution in propylene glycol / triethanolamine:
Start with 13.4 ml hot triethanolamine (hotplate at 100degC)
25 ml hot propylene glycol
11.5 g ascorbic acid
0.15 g phenidone

Stir until all solids have dissolved (it will take quite a while, and may require the addition of 1-2 ml of water). Dilute with hot propylene glycol to a final volume of 50 ml.

Solution turns brown after about 6 months!

Make 15% Sodiumsulphite (anhyd.) solution and distribute to smaller bottles with either 60 ml (35mm) or 100 ml 15% sulfite solution. Fill completely with MQ ( that is destilled water, actually Millipore filtered) to avoid oxidation.

For 35 mm film, equal to Xtol 1:1 (end volume 300ml):

7.5 ml InstantMytol + (15 gr sulfiet);
Small 100 ml bottle with 60 ml 15 % sulfiet, fill with MQ.
(to prevent oxidation to sulphate)

For 120 film, equal to Xtol 1:1 (end volume 500ml):

12.5 ml InstantMytol + (9 gr sulfiet);
Small 100 ml bottle with 100 ml 15 % sulfiet, fill with MQ.

(btw dispensing the viscuos liquid is not easy, I use a very small 10 and 20 ml graduates for that, and even than it take effort and thorough rinsing of teh graduate)

 

[albada]

I am test driving InstantMytol now for about 6 months, and have been very satisfied with it, so I wonder why you did not give that formula a try (or perhaps you did).

Welcome back, Cor!

Yes, I tried Instant Mytol a while ago. But I noticed some problems with it:

* Using TEA from Photographer's Formulary (85% pure), the pH was too high. In fact, I mixed Instant Mytol three times, but the high pH produced negatives that were too dense and grainy. Using a 99%-pure TEA available elsewhere might have helped. But the problem remains: TEA is different depending on where people buy it.

* It oxidizes quickly. Here's what mine looked like after two months:


* It uses 50 ml of concentrate per litre (1+19 dilution). I wanted higher concentration.

* As you point out, its viscosity is high (it's thick), making it hard to pour and measure.
​

While experimenting with concentrates, I made two discoveries:

1. Sodium metaborate dissolves in propylene glycol. Normally, inorganic salts don't dissolve in organic solvents, but sodium metaborate is an exception.

2. Ascorbic acid is easier to dissolve in propylene glycol if you have dissolved some sodium metaborate in it first. The metaborate helps the ascorbic acid to dissolve faster.
​

So I've been researching concentrates that take advantage of these two discoveries. The concentrate that Alan quoted above is my best so far that uses Phenidone. It only uses propylene glycol as the solvent, so it's easy to pour and will not suffer the inconsistency of TEA. It is diluted 1+49 (use only 20 ml per litre), and my tests so far show that it matches XTOL. This type of formula looks promising, which I call SMAP -- Sulfite/Metaborate/Ascorbic/Phenidone.

Mark Overton

 

[albada]

Alan; Back to the old argument. Well, tablespoons vary a bit in the US, and chemicals vary in crystal habit from batch to batch and even in one batch. I have found a variation of greater than 20% just due to crystal habit. This is often not accurate enough. It depends on the effect of the chemical in question. PE

+1
Electronic gram scales are available for only $10 to $15!
Search for "gram scale .01" on amazon.com. Here they are:
Dead Link Removed

Cost cannot be an objection at such a low price, and it solves all measurement issues. Weighing powders is more accurate. I prefer to weigh liquids as well, as it's more accurate and convenient.

Mark Overton

 

[kb3lms]

You've gotta watch those electronic scales from Amazon. I bought one a year or so ago and later found that it is exactly 1.5 grams off across the board. Haven't found a way to zero it although you would think there would have to be one. The electronic scales can work but you have to make sure you get a good one. Some are and some are not. I got a brand called AWS. Probably not the best. Thankfully I did not pay much for the scale although I messed up a few concoctions with it.

For a few dollars more, careful shopping on the auction site will get you a used Ohaus triple beam balance. There are other brands that likely work just as well for our purposes. I paid right around $30 for mine. Little cleaning and it is just like new and right on the money every time.

If you want to mix developers and such you really want a respectable scale. Top of the line is not necessarily needed though.

 

[Photo Engineer]

You can buy sets of weights in English or Metric values. These can be used to either calibrate or verify the calibration of your scales.

I have two digital scales and several sets of calibration weights. With mine, I just put a weight on the scale and then press the calibrate button.

You press the button and it does the rest. Hmmm, that sounds familiar!

PE