Borax Second Developer Question

[jolefler]

I'm finally getting around to playing with 20 Mule Team Borax as a second developer, but still have a question or two.

How much (what ratio) dilution are you folks using? I tried making up a 12oz. bottle to use with a single reel tank and found I couldn't get that much borax to stay in solution without precipitating out. I mixed it at 120 deg F, then let it cool overnight. When I ran the film, I just poured out the clear solution, leaving the precipatate in the bottom of the bottle. I used it as a 5 min. bath immediately following the first developer, with no rinse between them.

By eyeball, I find the negs to look good with slightly more detail in shadow areas, will try printing on Friday. It's just perplexing guessing how much borax will stay in solution without precipitating. Thanks!

Jo

 

[dancqu]

It's just perplexing guessing how much borax will stay
in solution without precipitating. Thanks! Jo

About 5% is it although that may be the anhydrous.
Likely 5% is more than enough. I'd suggest
something more like 1 to 2 %. Dan

 

[gainer]

Make a saturated solution at 18 C. That means put more in the pot than will dissolve at that temperature. Now the water of crystallization has no bearing. Siphon off the clear solution for use as part B. As long as your temperature of development is above 18 C the concentraion of borax by weight will be the same for practical purposes. IOW, grams of borax/gram of water will stay the same. Grams of borax per liter of solution will vary somewhat with temperature, but then so will concentrations of all other ingredients.

Borax is a very good pH buffer. It's action in a developer is to control pH. The concentration will have an effect on the rate at which change in pH due to development products can be corrected.

 

[Paul Verizzo]

You do realize that a borax solution will never get much above about 9.5 pH. There's hardly any difference between 20 or 40 grams per liter. Very flat curve. Five grams per teaspoon, 15 per table.

 

[justpete]

I'm finally getting around to playing with 20 Mule Team Borax as a second developer, but still have a question or two.

By eyeball, I find the negs to look good with slightly more detail in shadow areas, will try printing on Friday. It's just perplexing guessing how much borax will stay in solution without precipitating. Thanks!

Jo

I ended up at 4gm Borax decahydrate per liter distilled water after experimenting with dilutions of a saturated solution (60gm/liter at 52C). At this low dilution the buffering capability is minimized (less than 0.025M) allowing the pH at the film surface to drop extending development time and from my experience anyway allowing for a much wider process window.

Tested this with HP5+, 400TX, Arista EDU Ultra 200, and 125PX so far, all at box speed and found +/-20% had little effect in combination with PF's divided D76. Target was 0.42 CI derived from transmission densitometer data from six stop exposure steps.

And the 4gm of borax will dissolve on its own, no need to mix and mix and mix.