D-76 recipe questions

Kodak's D-76 SDS sheet lists borax as being the pentahydrate version. I have the 20 mule team borax which I believe would be the decahydrate. Going from penta to deca would be doubled the water. I will be mixing my own. Should I be using double the amount of borax, from two grams to four, for the home recipe and go by D-76 current development times or will it not matter? Also do the ingredients need to be mixed in a certain order for D-76? From past mixing D-23 I used a pinch of sulfite before adding the metol and then adding the rest of the sulfite in.

Many of the recipes for making D-76 do not show boric acid. That is one chemical I do not have. I read that it aids in balancing the pH though I will be letting the mixture settle for about a day or so and will be using it one-shot. Can the boric acid be omitted? If not then what version of it would be needed?

Thanks

Use 2.6g of decahydrate (2.62g to be precise).

The original D-76 formula (J.G. Capstaff) does not have Boric acid.

"Darkroom Cookbook" 5th edition, by Steve Anchell; Formula #10, page 307.

Mix in order given:
Water @ 125F/52C, 750ml
Metol 2.0 g
Sodium sulfite 100 g
Hydroquinone, 5g
Borax, 2g
Water to make, 1.0 liter

As to the Borax it is noted on page 406: "Borax is available as borax, pentahydrate but most commonly as borax, decahydrate, the form used in photographic formulas."

So it seems to suggest that the Borax amounts in the Darkroom Cookbook are decaydrate; which is what I use to mix my own D-76.

Andrew O'Neill said:

Use 2.6g of decahydrate (2.62g to be precise).

Click to expand...

Thanks, Andy. My scale does two decimal places so this works out great. This borax will last a good while.

Kino said:

The original D-76 formula (J.G. Capstaff) does not have Boric acid.

"Darkroom Cookbook" 5th edition, by Steve Anchell; Formula #10, page 307.

Mix in order given:
Water @ 125F/52C, 750ml
Metol 2.0 g
Sodium sulfite 100 g
Hydroquinone, 5g
Borax, 2g
Water to make, 1.0 liter

As to the Borax it is noted on page 406: "Borax is available as borax, pentahydrate but most commonly as borax, decahydrate, the form used in photographic formulas."

So it seems to suggest that the Borax amounts in the Darkroom Cookbook are decaydrate; which is what I use to mix my own D-76.

Click to expand...

Thanks, Kino.

Well, isn't that interesting!

I guess whatever formula you mix, just stick to it unless it doesn't work well for your applications.

I am thinking of mixing a batch of D-76H myself (no Hydroquinone) to offset the aging gain in PH and developer strength.

Kino said:

I guess whatever formula you mix, just stick to it unless it doesn't work well for your applications.

I am thinking of mixing a batch of D-76H myself (no Hydroquinone) to offset the aging gain in PH and developer strength.

Click to expand...

That last part is on my mind. There is a hold period after mixing, for a good day, and then the changes of pH later on. I was reading some of PE's past stuff about HQMS and sodium hydroxide being involved and it sounds like a roller coaster The D-76H version was by Haist?

Yes; thus the "H' (Haist) designation applied by Anchell in the Cookbook.

The "H" variant is not complex:

Mix in order given:
Water @ 125F/52C, 750ml
Metol 2.5 g
Sodium sulfite 100 g
Borax, 2g
Water to make, 1.0 liter

A slight bump in the Metol and eliminate the HQ.

I tend to neglect the darkroom for extended periods and whatever D-76 (classic) I have mixed in the past is always looked upon with suspicion, so I tend to mix a fresh batch before continuing. Not very economical or environmentally nice, so maybe I can start using the H variant to avoid having to dump the leftovers from the previous mix.

I always age my mixes for 24 hours before use.

The Darkroom Cookbook is a bit pricey but well worth the money; be sure to get the 5th edition (30th Anniversary).

It's easy to Google conversion factors for various molar weights of the same chemical. For Borax decahydrate/pentahydrate a quick search turns up a factor of 0.764, meaning that to find how much pentahydrate you need when the recipe calls for decahydrate, you multiply the decahydrate amount by 0.764.

To do the opposite, which is what you want to do if the recipe specifies pentahydrate to start with, you multiply by the reciprocal of that number (divide 1 by 0.764 in this case to give 1.31 approximately). For example, if the recipe calls for 2 grams of pentahydrate, 2 x 1.31 = 2.62. You know that already, but if you want to make a different amount or have the same problem in the future with a different chemical, you can just find the factor online and calculate the amounts yourself.

I believe the Darkroom Cookbook has tables for conversions of different molar weights of the same chemicals as well.

Best,

Doremus