Thornton's Two Bath

[blackmelas]

BATH A
Metol- 6.25gr
Soduim Sulfite- 85 gr
Water to make 1 liter

BATH B
Sodium Metaborate- 12gr
Water to make 1 liter

ca. 3 min each bath iso 50 films
ca. 4 min each bath iso 100 films
ca. 5 min each bath iso 400 films

The late Barry Thornton reformulated Stoeckler's Two Bath recipe for thinner modern films. Comments on this?

Do not presoak or rinse between baths. Agitate every minute or more in bath A then empty. Pour in bath B smoothly and simply give a rap on the counter to dislodge air bubbles. I give at least one inversion at the mid point in bath B.

Thornton claimed you could get at least 15 rolls out of the A and B solutions (this I've tested to be true though the B had a putrid smell at the end) and that bath A lasted for up to a year (Have not tested this).

my personal times are 2:15 in each bath for Maco ORT25, Efke 25; 2:45 in each bath for Pan F; and 3:45 in each bath for FP4+.

[davekarp]

In Edge of Darkness, Thornton gave the formula with 6.5g / liter of Metol, rather than the 6.25g / liter given in earlier formulations. I E-mailed him before he passed away, and he told me that the 6.5g / L version was his preferred version.

[oldglass]

A few questions specifically about mixing the chemicals:

1. Do I basically just measure, pour and stir? or do I need to boil/warm the water, etc.?

2. After I mixed according to the formula (in the first post of this thread), do I end up with concentrate solutions or working solutions? if concentrates, how much dilution is recommended to make the actual working solutions?

Sorry for the basic questions, but I sure can't get the answers easily by searching online.

[Dwane]

A few questions specifically about mixing the chemicals:

1. Do I basically just measure, pour and stir? or do I need to boil/warm the water, etc.?

2. After I mixed according to the formula (in the first post of this thread), do I end up with concentrate solutions or working solutions? if concentrates, how much dilution is recommended to make the actual working solutions?

Sorry for the basic questions, but I sure can't get the answers easily by searching online.

1. Yes - measure, pour and stir. Use warm (125 deg.F, 52 deg.C) distilled water.

2. You end up with working solutions. Use the solutions just as suggested by blackmelas in his first post.

[corsaaaire]

Hi all,

I did read Edge of Darkness and tried Barry Thornton two baths developer on HP5+ EI400 in 120 format last week end.
What would happen if i let the film longer or less time in each bath ? Would the highlights raise higher like in a normal developer ?

What time of development do you suggest me please for HP5 rated at 400, and for 200isos ?

Best regards,
Lionel

[Alan Johnson]

There is some info for the similar Stoeckler developer:
www.largeformatphotography.info/twobath/
I don't think similar test results are avalable for Thornton's.

[corsaaaire]

Thanks for your answer Alan.

I had tried Thornton two baths with FP4+@100 and i like much more than with HP5+. The tones are nicer.
I still find more grain than with ID11, should i add more sodium sulfite like in D-23 formula ?

I had some uneven development on my negs if i don't agitate any of the two baths.

On the link you provided, it is said to change time in first bath only if i want to increase or decrease global contrast, it sounds logical, whereas Thornton suggested to put more or less sodium metaborate in second bath to achieve N-1 to N+1 development.
Have you guys tried one of these methods ? Do you have some times for iso 100 or 50 i should start from for my tests?

[Alan Johnson]

My measured results were only for Delta 100 developed in Thornton's with 12g/L metaborate for 4 min + 4 min 70F as per Edge of Darkness (ED), agitating 2 initial inversions then 2 inversions/min. This gave EI=80 ,average metering,sun/shade.
In ED p94 sodium sulfite was reduced to cut down grain dissolving activity and increase sharpness so it would be expected that increasing sulfite again would have the opposite effect.
The link indicates longer times in A increase contrast,ED p95 notes that increasing metaborate does the same.
At a guess it seems quite likely that EI=50 or EI=100 could be obtained by varying the time,at least with Delta 100 and quite likely FP4+.If the contrast is not satisfactory it might be adjustable by varying the alkalinity,metaborate concentration, as Thornton suggests,only experiment can tell if speed and contrast can be balanced in this way, I have not seen results from others on this.

[Mark Booth]

Dave Karp is right in his observation that Barry's revised formula called for Metol 6.5 grams instead of 6.25 grams. I had dialogued with Barry on a regular basis for about 3 1/2 years prior to his untimely death. In fact, we were talking about planning some time together doing some photography in the UK. Photography really lost a master photographer and passionate teacher to all.

I have developed many hundreds of rolls of film with the Barry Thornton 2-Bath developer over the years, and have found it particularly useful for roll film processing. (IDEAL FOR: many images with variances in exposure or contrast scenes, or processing in one large tank several different film types are made easy with the 2-Bath process).

While most of my work is now done with sheet film—pyro and brush development by inspection method, I find Thornton's formula hard to beat particularly for anyone not requiring (or desiring) a tanning and staining developer. If one desires a little added sharpness without inducing grain, one can add 6-9 grams of sodium ascorbate (vitamin-C buffered) to bath A and develop as usual with little change in contrast. But, in reality this developer is just so nicely balanced that tweaking it too much defeats its purpose in my way of thinking. Simplicity is such an important key in the quality and elegance of a good developer. Simplicity of formulation also allows one to learn more easily the behavioral characteristics and cause relationships (influences) between developing agents and constituents. While I like the use of sodium metaborate because of its balance with contrast and grain combination, one can use borax for finer grain or sodium carbonate for increased sharpness. But for all intent and purposes, all images will work very well with sodium metaborate as the activator in bath B.

[Jonathan R]

This is my one and only developer these days. I started with Tetenal's Emofin, but after some years on that with 35mm Tri-X I found myself disatisfied with a mid-tone muddiness. So I switched to the Thornton 2-bath. I like it best with HP5+, second best ith FP4+, but it also works very nicely with Tri-X and Delta 100. I see no reason to search further.