sodium metaborate - temperature sensitive?

[gonzalo_echeverria]

hi,

 

could anyone clarify whether sodium metaborate as 'b' bath, in combination with metol

and sodium sulfite as the 'A' bath, is affected by temperature variation?

 

i'm in Australia and its starting to get cooler here and my negs are starting to look like they

lack development ( great shadows - long scale ) .

 

all suggestions and comments welcomed!

[ed_hurst]

Can't help you with your main question, but I doubt that "great shadows - long scale" indicates simply lack of development. Lack of development on its own would probably lead to lack of shadow detail. Your symptoms sound more like exposing generously (downrating film) combined with reduced development.

[kirk_keyes]

Are you using fresh A solution - perhaps it is getting old and loosing activity?

[lowell_huff1]

Sodium meta borate is mildly alkaline in pH; it sounds like you have no developeing agent in this formula.

[john_finch]

Sounds like you are using a two bath developer. That is, you have a complete developer in the A bath and are using the B bath to tame highlights.

 

temperature will effect the A bath just as it would if that were the only bath you were using (you could develop the film by only using the A bath in this, your described case). The B bath should be the same temperature as the A.

 

If you need more contrast use a longer time in the A. Use the 10% rule. That is, if you know the time you use at 20C and it is only 19C then add 10% to the time.

 

Hope this helps.

[gonzalo_echeverria]

- to my understanding , metol should keep for a long time ( 12mths ) in 80g to the litre.

- Lowell, sodium metaborate is the metol's activator

- Kirk, could be. i was under the impression that its the alkaline activator in a developer that

exhausts, not the metol. bath A is purely there to supply the small amount of metol that is

absorbed into the emulsion, then the sodium metaborate kicks in.

- John, yes, A is a complete developer - a modified D23 ( 8% sodium sulfite as opposed to

the original 10% ). B bath is used to give normal contrast with highlights in check.

 

thanks everyone.

[patrick_gainer]

The short answer is "Yes." You can find the web site by Googling "20 Mule Team". At that site you will find about sodium metaborate, how pH varies with temperature and how the molecular structure varies from 4 mol to 8 mol thus giving rise to the myth that it makes a difference to us.

[lowell_huff1]

Gonzalo:

You mention that your negs lack development but have long scale. The scale is a function of the metol. If you add a developer, hydroquinone, you will get the density you require.