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Benzotriazole is added to keep fogging on old outdated films to a minimum level.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.

No comments:

Post a Comment