Velox Developer formula Nepera Solution

Rlibersky submitted a new resource:

(there was a url link here which no longer exists) - Velox Developer formula Nepera Solution

Elon (or Metol) .5g
Hydroquinone 2g
Sodium Sulphite (cryst.) 15g
Sodium Carbonate (cryst.) 27g
Water 300cc
Potassium bromide, 10% Solution 20 drops

This developer will keep well in bottles filledd to the neck and tightly corked. It should be used without further dilution. The best results are obtained with this developer at a temperature of 65-68 Fahr. (18-19C)

This is exactly the same as Selectol except for about 3x as much Carbonate. Not sure what effect this might have.

It...

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(there was a url link here which no longer exists)

Comments from previous article system:

By psvensson - 02:57 PM, 11-04-2005 Rating: None
I wonder why they gave 300ml as the default batch. Was this for development in 4x5 trays or something?

By Rlibersky - 07:06 PM, 11-04-2005 Rating: None
I was wondering that as well. Your thought makes sense to me. The paper was 3.25x5.25. I just got some 8x10 Velox I'll see if the formula is different.

By Gerald Koch - 07:16 PM, 11-07-2005 Rating: None
300 ml is 10 fluid ounces which was a popular volume for developer formulas when this formula was devised in 1911. Since then it has been converted from english to metric measure.

By Gerald Koch - 07:47 PM, 11-07-2005 Rating: None
This is D-72 in disguise. Crystalline sodium sulfite is the heptahydrate and crystalline sodium carbonate is the decahydrate. Making the adjustments to anhydrous sulfite and monohydrate carbonate and multiplying by 6 produces

Metol ...................... 3.0 g
Hydroquinone ........... 12.0 g
Sodium sulfite .......... 45.0 g
Sodium carbonate ..... 81.3 g

By Rlibersky - 10:07 PM, 11-07-2005 Rating: None
Just shows you haow long that formula has been around. Not even a Kodak invention, if you are correct.

The Nepera Velox formula - as published by Eastman Kodak in 1905 is:

Hydroquinone 2 g
Sodium Sulphite (anhyd) 7 g
Sodium Carbonate (anhyd) 13g
Metol 0.5 g
Potassium Bromide 10% 40 drops
Water to 300 ml

What is interesting is they used the correct English spelling of Sulphite, don't use the Kodak Elon trade name for Metol and also give the formula in Metric, also Sulphite & Carbonate are shown as Dessicated, which is anhydrous in modern terms.

The formula doesn't match Dektol, D72, or Selectol, D52. There is significantly more carbonate and far less bromide. Velox papers were in production for many years, and later Kodak recommended D-158 or the Metol free D-173.

Ian

"What is interesting is they used the correct English spelling of Sulphite, don't use the Kodak Elon trade name for Metol and also give the formula in Metric, also Sulphite & Carbonate are shown as Dessicated, which is anhydrous in modern terms."

Ian,
That's probably the original formula written by a Belgian chemist,who invented Velox and started the Napera chemical co.
He later sold out to Kodak for a cool $1 Million Bucks(1889)......parlayed that into the invention of Bakelite(plastic) which was later sold to Union Carbide.

-Don

http://en.wikipedia.org/wiki/Leo_Baekeland

Nepera solution also mentions auxiliary powder "capsules" for film development. That is even more interesting