Progress on XTOL-concentrate

[richyd]

Thanks for the work on this, I've wanted to try XTOL but making 5 ltrs is impracticable. I'm about to purchase the chemicals and the Sodium Metaborate (Kodalk) I can obtain is 8 mol. Could you advise on any correction to the amount of this to use, although I did Chemistry that was over 35 years ago!

Many Thanks.

 

[albada]

I was still experimenting with my borax-carbonate version. LegacyPro 400 5.5min look ok. my other experiment is decreasing amount of sodium sulphite from 90g/l to 30g/l. amount of borax is same, but I need increase amount of carbonate for correct pH 8.3. formula:
Sodium sulfite 30g
Phenidone 0.1g
Ascorbic acid 8.5g
Borax 6.3g
Sodium carbonate 3.3g
Water 1l
pH=8.3
compared to 90g/l version this developer give less density for same time. more grainly, but sharpness is excellent. sample images for LegacyPro 400 5.5min in attach

Sulfite helps the developer to develop faster, so when sulfite is reduced, density will decrease, even at the same pH. You need to develop longer if using low sulfite.

6.3 g of Borax has the same number of boron atoms as 6.7 g of metaborate, but it has much fewer moles of molecules, so I think buffering will be worse. I suggest increasing acid and alkalis to improve buffering like this:
sulfite=90, ascorbicAcid=9, borax=10, s.carbonate=??, phenidone=0.1
Adjust s.carbonate to give pH=8.3. More than 10g of borax would be better, but it might take too long to dissolve.

The left scan in your images looks like the scanner was slightly out of focus. It is difficult to focus scanners accurately to measure grain. Can you re-scan that negative with manual focus on that part?

Mark Overton

 

[albada]

Thanks for the work on this, I've wanted to try XTOL but making 5 ltrs is impracticable. I'm about to purchase the chemicals and the Sodium Metaborate (Kodalk) I can obtain is 8 mol. Could you advise on any correction to the amount of this to use, although I did Chemistry that was over 35 years ago!
Many Thanks.

Firstly, Welcome to apug! (I notice this is your first posting).

You'll need 9.1 g of sodium metaborate 8 mol.
The ratio of the molecular weights of 8 mol and 4 mol = 137.88/101.83 = 1.354, which multiplied by 6.7 gives 9.1.
8 mol contains more water than 4 mol, so if you're mixing it into propylene glycol, I suggest letting it sit for 15 minutes at 90C to steam-out the water.
Don't let it get much over 90C or the PG itself will evaporate. Don't ask how I know.

Mark Overton

 

[albada]

Tap-water scan

Here are full-resolution (2900dpi) neg-scans of photos of a Stouffer wedge shot on TMY2. The left scan was developed in distilled water, and the right in a tap-water solution that was allowed to sit for one hour at 20C before usage. It had some cloudiness visible in specular side-lighting, which was the beginning of precipitation.

Distilled: Tap-water:

Yes these pictures are boring. But I don't see any degradation in the dark or light areas in the right scan. Nor do I see any issue in a 22X loupe on the light-table. The cloudiness appears to have had no effect. If waiting an hour doesn't hurt anything with hard tap-water, I'm questioning whether it's worth putting a chelating agent into this one-shot formula. I guess I should run more tests to see how severe the cloudiness must be before it affects image-quality.

Mark Overton

 

[Kirk Keyes]

What's in your tap water? Your local water bureau can tell you that. PE has said that Kodak had water with extra minerals found in some municiple waters on tap for use in their lab testing!

 

[albada]

What's in your tap water? Your local water bureau can tell you that. PE has said that Kodak had water with extra minerals found in some municiple waters on tap for use in their lab testing!

According to my shower, plenty of calcium. We get an annual report from the water district, and I'll look closer next time.

Last night, I let tap-water-based developer sit for an hour at 30C, which is roughly equal to two hours at 20C (thanks again for that correction). The test-strip shows no sign of speckling, despite obvious cloudiness in the dev. BTW, the precipitation was still staying in suspension, so it hadn't gotten far enough along to start settling to the bottom. This dev will be used soon after mixing, so I don't think any precipitation will progress enough to cause harm.

But remember that white cloudiness and scale in the concentrate (not water-solution) that I reported a week ago? It was triggered by mixing-in the Dimezone last, but did not occur when mixed first. Well, it even occurred in the concentrate where the Dimezone was mixed first. It just took a week to start. This also happened months ago with a highly concentrated dev I tried. But it has not happened in less concentrated samples that are six months old, nor has Alan Johnson reported it about his bottle of D316.

If you define "concentration ratio" as GramsOfPowders / MlOfFinalVolume, then the failing samples had ratios of .46 and .63, and the successful samples had ratios of .35 and .33. So I'm suspecting that when concentration ratio gets much above .35, the concentrate becomes susceptible to this crystallization-problem that PE described (there was a url link here which no longer exists). If so, then I need to reduce concentration, and I have some ideas for that. One is to reduce the ascorbic acid some, which will also reduce the metaborate. Another is to replace some of the metaborate with TEA. Or one could simply add more propylene glycol. If somebody has suggestions about this, I welcome them...

Mark Overton

 

[Alan Johnson]

Just to confirm that D-316 is still clear with no precipitate at 6 months old.
It has a concentration ratio (2.2+4.5)/20 = 0.335

 

[Athiril]

Get your hands on potassium sulphite or potassium metabisulphite (and react it with potassium hydroxide beforehand) if you want to make a high-sulphite concentrate.

I've made a very high phenidone-ascorbate concentrate, but using potassium ascorbate. React the AA prior with a potassium salt like KOH. Shouldn't need as much sulphite for preservative with high ascorbate content. If you want to add salicylic acid, just use supermarket aspirin, it will hydrolyse in solution to salicylate.

If then the only role left for sulphite is to act as a fine grain solvent. You could use a very small amount of potassium thiocyanate (as in a non-highlight clearing/non-reversal amount for the process times).

My current concentrate is a bit different I made is similar, 4-aminophenol, potassium ascorbate and CD-2, still good after over a year, with some floating precipitate (saturated solution, like this since fresh). It is 1+24 to 1+49 dilution (20 min for HP5+ etc at 1+49), produces a negative that has higher local contrast with better micro details, but prints on a higher grade filter for the same black to white range (good for high contrast subjects already printing at 0), has more accentuated grain though.


If you want a very high keeping life of concentrates, if you're going to split it into a 2 part solution anyway, making the part with the developing agents pH 4-6, with potassium metabisulphite and/or ascorbic acid etc, should increase the shelf life due to lower pH.

 

[albada]

Could folks do me a favor and tell me which crop below is grainier? Even if they look the same to you, please post a note so I'll know:

XTOL:

TEA-mod:


The second is the concentrate with some TEA added, and I'm trying to decide if it's worth pursuing this modification. And please don't laugh about the water-spots and dust; I was casual about cleanliness because these are just test-strips. Here are the density-curves:



From a density point of view, the modified concentrate is identical to XTOL. But I'm trying to decide about the grain. For the curious, here's the formula. In my test, I dissolved these directly into water:

Propylene glycol .................... 22 ml
TEA85-DEA15 ....................... 3.4 g (yes, that's grams, = 3.1 ml w/ sg=1.107)
Sodium metaborate 4 mol ..... 3.5 g (dissolves in 3-5 minutes. let sit to dry) (4.9 to cnv AA)
DimezoneS/Phenidone .......... 0.2/0.105 g (DimezoneS dissolves in 3-5 minutes. turns orange)
Ascorbic acid ......................... 8 g (dissolves in 7-10 minutes; fizzes and turns clear)
Propylene glycol to ................ 33.3 ml (final volume; should need to add little)

Heat to 90C to dissolve everything and drive the water out of the metaborate.
Dissolve in the order shown, and dissolve completely before adding the next chemical.
To make one litre of developer, mix 33.3 ml of concentrate into water containing 85 grams of sodium sulfite. That's 1+29 dilution.
Times are same as XTOL. Target pH is 8.32.
Concentration ratio = 11.7/33.3 = 0.35
​

I took the prior concentrate, reduced the ascorbic acid and sulfite a little, and substituted TEA for about half the metaborate. My first test showed that, all other things being equal, TEA gives greater density than metaborate. Alkalis are not created equal. PC likes TEA.

The TEA, labelled "TEA85-DEA15" above, is from Photo Formulary, and their MSDS states that it's 85% TEA and 15% DEA (or slightly more TEA). I tried it a few months ago, and got frustrated because nothing about this TEA agreed with the spec's: specific gravity, pH in solution, and even the freezing point. Whatever is in there, I'm sure it's mostly TEA, but I think of it as "mystery TEA". I'd want to get another sample before recommending this formula. Actually, I'd prefer to use 99% TEA (and boost the 3.4g a little), but that's harder to get in the USA (but easier in Europe).

@athiril: You have an interesting developer using CD-2. Please post that to a new thread where it'll get more visibility.

@Alan Johnson: Thanks for the confirmation. I'm becoming leery of a concentration ratio over 0.35. Maybe I should mix a 0.40 to see if it crystallizes. I'm wondering what the threshold is.

Mark Overton

 

[Photo Engineer]

Mark;

The second strip is much less sharp than the first one for whatever reason. Thus it is hard to judge graininess.

PE

 

[albada]

Mark; The second strip is much less sharp than the first one for whatever reason. Thus it is hard to judge graininess. PE

The camera was misfocussed a little in the second strip, so the boundary lines are soft. But that has no effect on graininess, and the scanner was carefully focussed in both scans, so the grain should be equally sharp in both.

Mark Overton

 

[Photo Engineer]

I would have to say they are close, but perhaps #2 is grainier.

PE

 

[Athiril]

@athiril: You have an interesting developer using CD-2. Please post that to a new thread where it'll get more visibility.

Will do so when I get more reliable internet.

 

[john_s]

I'll answer instead of Mark: Photo Formulary sells sodium metaborate which according to their MSDS is sodium metaborate 4 mol. This MSDS lists the formula NaBO2·2H2O [Na2B2O4·4H2O]

Likewise there is a reference on http://www.borax.com which lists both 4 mol (NaBO2·2H2O) and 8 mol (NaBO2·4H2O) sodium metaborate. So for all practical purposes I would assume that Mark means the 4 mol compounds as defined by these references: NaBO2·2H2O

The confusing names seem to come from the double compounds Na2B2O4·4H2O and Na2B2O4·8H2O

Confusing naming indeed. More confusing than the usual question of the degree of water of crystallization in compounds like sodium carbonate where at least if it's labeled correctly we get only one version, e.g. monohydrate, decahydrate etc.

So confusing, in fact, that www.borax.com have made a mistake in their product data sheet for the 4-mol. See page two, top right, where 4H2O should read 2H2O.

I wonder which version my sodium metaborate is (bought at Vanbar Melbourne). It didn't matter much with PMK because Part_B was pretty much a saturated solution and some people varied the relative amounts of Part_A and Part_B anyway. But in this interesting concentrated Xtol-like developer I would guess that the pH would be sensitive to errors in the exact amount of metaborate.

 

[Photo Engineer]

If the pH is correct, then the developer should work properly. The major difference is the buffering capacity. If you figure out the number of moles of boron you want present, then you can make the right mix from boric acid and Sodium Hydroxide.

PE

 

[Gerald C Koch]

Actually, I'd prefer to use 99% TEA (and boost the 3.4g a little), but that's harder to get in the USA (but easier in Europe).

The Chemistry Store www.chemistrystore.com sells 99% TEA. Since their main clientele use it to make soaps and lotions it cannot contain any DEA or MEA. You can check out the MSDS for the chemical on their site. One gallon sells for $16.84 plus shipping.

 

[albada]

The Chemistry Store www.chemistrystore.com sells 99% TEA. Since their main clientele use it to make soaps and lotions it cannot contain any DEA or MEA. You can check out the MSDS for the chemical on their site. One gallon sells for $16.84 plus shipping.

You bring up a subject I've been wondering about.
At PhotoFormulary, one gallon of TEA (85%-15%) costs $49.95.
At ChemistryStore, one gallon of TEA (99%) costs $16.81.
That's a much lower price for a better product.
So I suspect that the 99% in the ChemistryStore's MSDS is a mistake.
Or how could they sell a high-grade product so cheaply? What do you think? Have you found that their TEA behaves like 99%? If so, I'm buying some now!

@PE: I feel silly asking this, but is buffering capacity determined by the number of boron atoms, or by the number of molecules of borate? If it's by the number of boron atoms, we could substitute one fourth the moles of borax (vs metaborate) because one borax molecule contains four boron atoms (vs one boron atom in metaborate). Relayer would be interested in this.

Mark Overton

 

[Gerald C Koch]

Mark

A bought a gallon awhile back and it is indeed 99% pure. You can tell by the lack of smell. As far as PF is concerned, I won't buy from them. They are expensive and I wonder about the actual purity of the chemicals they sell. As I said the Chemistry Store's TEa is intended for topical use in lotions and so cannot contain DEA or MEA. The liquid is viscous, water white and has the correct Sp Gr for TEA 99%. I used it to make up an ascorbic acid developer (Dimezone, ascorbic acid, TEA, propyelene glycol) and it worked fine. They also sell several other chemicals that are of use in photography such as hypo. sodium sulfite, sodium carbonate, propylene glycol, Triton X-100, etc. They also sell PET bottles. Their prices are more reasonable than most other suppliers.

Jerry

 

[john_s]

You bring up a subject I've been wondering about.
At PhotoFormulary, one gallon of TEA (85%-15%) costs $49.95.
At ChemistryStore, one gallon of TEA (99%) costs $16.81.
That's a much lower price for a better product.
So I suspect that the 99% in the ChemistryStore's MSDS is a mistake.
Or how could they sell a high-grade product so cheaply? What do you think? Have you found that their TEA behaves like 99%? If so, I'm buying some now!
.........
Mark Overton

Retail prices are set at their levels for all sorts of reasons. Even here in Australia, where nearly everything costs more, 5L of 99% TEA cost me $20 (Aust dollars, at the time less than US dollars). I had to bring my own container. The vendor was a firm specializing in specialized lubricants for industry.

 

[Gerald C Koch]

Mark

Boric acid B(OH)3 and borates are a bit of a problem since boron likes to make B-O-B bonds. So the actual structures may be more complicated than the stochiometric formulas would indicate. If boron behaved normally you wound expect something similar to the following series of compounds which phosphorous exhibits; PO(OH)3, NaO2(OH)2, Na2O3POH, Na3O4P. As one goes from phosphoric acid to sodium dihydrogen phosphate to disodium hydrogen phosphate to trisodium phosphate the pH rises so that the trisodium salt is a very strong alkali almost as strong as sodium hydroxide. For borates with complex structures you simply cannot base alkalinity on the number of boron atoms in the molecule.

In the titration of boric acid you would expect to see a three step curve as each of the three OH groups is neutralized. However what is seen is a somewhat smooth rise in pH as NaOH is added. To see the steps clearly the simple sugar mannitol is added to the solution to break any B-O-B bonds. The boric acid then behaves more like a normal acid and exhibits a three stepped curve like phosphoric acid.

Jerry

 

[Photo Engineer]

To add to what Jerry said, buffer capacity can be looked at as the total number of moles of alkali present in a solution. Thus, water has zero buffer capacity and lets say that it is at pH 7 (protected from CO2 in the air of course). So, if we add a pH 7 buffer, then the buffer capacity rises but the pH stays constant.

Addition of dilute acid or base to plain DW will change the pH rapidly, but adding dilute acid or base to the buffered DW will cause a slower change if any takes place at all.

PE

 

[albada]

Jerry and john_s:
You've convinced me! I'll be buying some 99% TEA from ChemistryStore this evening, and I'll adjust the developer formula.

And thanks for the postings about the interesting behavior of borates and buffering. The more I learn about chemistry, the more I appreciate how many things need to be determined (or at least verified) by experimentation.

Here's a modification of the TEA-based concentrate versus XTOL:



Notice the slight elbow at 1.5 on the X-axis. I've seen that before, and I suspect it's due to rotating developer in the tank developing the outside of the test-strip more than the center. So I'll be making baffles to stop movement of liquid and run more strips. As Michael R pointed out, we're down to such slight differences that a micro-densitometer is needed, and I don't want to distort things with uneven liquid-flow.
Here are crops of the latest TEA-type concentrate:

Xtol: , TEA con:
Xtol: , TEA con:

The densities aren't quite the same due to hassling with exposure on the scanner, but these should give you a good idea of the grain.

Mark Overton

 

[Photo Engineer]

Your TEA concentrate looks sharper and less grainy.

Good work.

PE

 

[albada]

Your TEA concentrate looks sharper and less grainy.
Good work. PE

Thanks for the encouragement. I guess the next step is to mix it as a concentrate and make sure it doesn't crystallize. And then comes the boring tests that must be done.

It occurred to me that since the crystallized stuff (with the high concentration ratio) has cream-like viscosity, it might be dispensed out of a squeeze-tube like lotion. But one would get controlled amounts of it by dispensing one of more strips onto the left portion of a ruler. Then one would use the ruler as a stirring-paddle when mixing the developer. This scheme has the advantages of very high concentration and ease of use, but I wonder if the cream will be subject to separation. In the bottle, due to excess PG, the top third is liquid and the bottom two thirds is cream. I don't know if the cream alone would separate into more liquid. Oh great, another idea to explore...

Jerry and john_s: The deed is done! I just gave $116.39 to the ChemistryStore.com for several chemicals. One third of that total is cross-country shipping.

Mark Overton

 

[Rudeofus]

Just curious: Jerry mentioned that (poly)borates react with mannitol which breaks up polyborates. Upon further investigation this reaction is not specific to mannitol, in fact many polyalcohols do this. Is there a chance that PG also does this? Could this mean that Mark's formulation already takes advantage of this effect?