Thornton's Two Bath - shelf life?

Jeff Bannow

Member
Joined
Mar 1, 2007
Messages
1,755
Location
Royal Oak, M
Format
Medium Format
I'm having trouble finding a shelf life for Thornton's Two Bath - anyone know, or want to hazard a guess? I would imagine it's fairly long, but I'm not sure.

I'd hate to not trust it - I've had D-76 go bad and ruin film before.

Here's the formula for anyone not familiar:

Part A:
750ml Distilled water
6.5g Metol
85g Sodium sulfite
Distilled water to make 1L

Part B:
750ml Distilled water
12g Sodium metaborate
Distilled water to make 1L

Use: Use solutions undiluted.
 

Ole

Moderator
Moderator
Joined
Sep 9, 2002
Messages
9,245
Location
Bergen, Norway
Format
Large Format
Very very long.
Metaborate is stable for years, and in an almost neutral solution the Metol should last as long.
 

Ole

Moderator
Moderator
Joined
Sep 9, 2002
Messages
9,245
Location
Bergen, Norway
Format
Large Format
What I really ought to do now is to shuffle up to my darkroom and dig out the bottles I mixed up three years ago. But it's winter, and my darkroom is unheated...

I'm quite sure mu chemicals are still good, though. you could risk a small peek with subdued light at the end of the processing; if it looks underdeveloped, just rinse and repeat until satisfied!
 

Alan Johnson

Subscriber
Joined
Nov 16, 2004
Messages
3,284
My Thornton's 2 bath stored in full sealed bottles was about 3 yrs old when I threw it out due to the negs apparently becoming less dense.I daresay the metol slowly hydrolyses though there is nothing in my books about this.
If kept in part full bottles the sulfite will react with oxygen from the air and the shelf life of the A solution will probably be about the same as that of D-76 under these conditions.
 

el wacho

Member
Joined
May 12, 2007
Messages
433
Location
central anat
Format
Medium Format
hi,

i've mixed up the 50g/L and 35g/L sodium sulfite versions of this developer and used them consistently for at least a year each without noticable difference in density. i was working with a condenser enlarger ( old axomat iia 6x6 ) so my negs were thinner than normal. i'm currently experimenting with a 20g/L sodium sulfite version. its about 2 months old and shows no signs of weakening so far - considering that i'm making the A bath to the grunt work - 10 minutes, inversion every minute and then 6 minutes in a B bath of 20g/L sodium carbonate (negs for diffuser colour head). it is suprisingly low in fog compared to my usual pyrocat hd ( metol version ) and sodium hydroxide - the film that i've been going through that was giving me problems with fog was 6 year old fuji acros. very little with this variation of thornton's two bath. hope this helps.
 
Last edited by a moderator:

georgegrosu

Member
Joined
Oct 15, 2007
Messages
434
Location
Bucharest, R
Format
Multi Format

Formula Barry Thornton - Two Bath - is tap water.
Dead Link Removed

I do not know if distilled water will contribute to a longer life of the developer.
Chemically speaking, the developer is quite stable.
I personally would not use any old developer more than a month. Photographic effect of developer can change over time.
Comfortableness often has a price.
If you love your films not try to use very old developer.
George
 

georgegrosu

Member
Joined
Oct 15, 2007
Messages
434
Location
Bucharest, R
Format
Multi Format
Usagi
I haven't used older than one year. But it should keep long. The color may vary a lot during usage, depending on the films
Fomapan 100 sheet film gives nice green tone to both baths.
Click to expand...
What do you think happens with to the 4-7 ml of developer (solution A) to be transported in solution B by film?
After the first, second, .... film?
Borax is so cheap that I do not think it worth the risk.
George
 

el wacho

Member
Joined
May 12, 2007
Messages
433
Location
central anat
Format
Medium Format
7ml of bath A works out to about 0.045 g of metol being carried over... but i fail to see the relevance. does it change the main function of providing an activating alkaline environment to finish development? you wouldn't use borax for this one because as Thornton stated in 'edge of darkness' , borax is a little soft working. he designed this one with a sodium metaborate B bath. when you use this developer as your main developer and 'tune in' to its nuances, it rewards with a particular look - nice S curve, nice local contrast in the mids. its a different way of working to the BTZS/jobo rotary processing - not better, just different. Tri_x 120 looks amazingly fine grained and very sharp.
 

georgegrosu

Member
Joined
Oct 15, 2007
Messages
434
Location
Bucharest, R
Format
Multi Format
I think that after going 10 films from developer would come about 0.45 g of metol. If we count the amount of developer absorbed from emulsion, I think we can reach almost 1 g of metol.
I appreciate that solution B is close to a developer composition.
For this reason I think it is good that the solution B is changed.
The film transition from developer in borax solution (without washing) is a less controllable phase and may lead to different photographic results.
I have not used this developer, but the principle on which it is built is good.
My personal suggestion is related to the regular change of solution B.
Use of sodium carbonate instead of borax, you probably have other results.
George
 
Last edited by a moderator:

el wacho

Member
Joined
May 12, 2007
Messages
433
Location
central anat
Format
Medium Format
experience trumps speculation...

since this was my main developer for at least 2.5 years i did get to see what happened to a B bath when it saw 20 - 30 rolls of film. the colour changes due to the build up of oxidized A bath BUT NO CHANGE İN ACTİVİTY. that means no change in contrast or speed. glad to be of any help Jeff.
 
You must log in or register to reply here.
Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…