It might be of interest for those who want to prepare their own E-6 solutions from raw chemicals that Fuji Photo Film discloses in their US Patent 6,720,134 (about Provia 400X) the exact composition of such solutions. There are some noteworthy differences to the E-6 recipes given by Derek Watkins (www.opie.net/orphy/photo/dr/wkft-e6.html not only in the replacement of sodium hexametaphosphate (Calgon) by Nitrilo-N,N,N-trimethylene phosphonic acid pentasodium salt, but also a higher concentrated and differently composed first developer with a shorter development time (4 min instead of 6 min given for the Fuji Hunt E-6 process manual).

Of particular relevance is the reversal bath which is based on the non-hazardous stannous chloride (SnCl2) dihydrate instead of sodium borohydride. Watkins proposes a reversal exposure step which might be more practicable for sheet film than for 120 or 135 format.

Washing appears to be done with water.

Accurate thermostatization and a pH-meter with proper calibration buffers are as essential as a good laboratory balance; if an analytical balance with 1 mg resolution is not available, higher concentrated stock solutions might be prepared and the appropriate volume dosed with a graduated pipet or cylinder. Use a pipetting aid and never pipet with the mouth, wear a laboratory coat, closed shoes, gloves and protective eyewear always when working with solid alkali reagents and alkaline solutions (carbonates, phosphates, hydroxides), acids (acetic acid, sulfuric acid, nitric acid) and all the other organic chemicals (developers, stabilizers, formaldehyde etc.), have washing bottles or tap water ready to wash off spilled chemicals from skin and clothing, keep the darkroom clean, well ventilated and do not inhale vapors - I am a chemist and know about the risks, dangers and hazards. Phenylenediamine-based color developers can induce allergies. Solid sulfites will develop toxic sulfur dioxide vapor upon contact with concentrated acids. Always add concentrated acid slowly into the water.

I am really tempted to try large format photography...

Always work at your own risk, but have fun!

Processing Tempera
Step Time ture volume
1st development 4 min 38° C. 37 L
1st washing 2 min 38° C. 16 L
Reversal 2 min 38° C. 17 L
Color development 6 min 38° C. 30 L
Pre-bleaching 2 min 38° C. 19 L
Bleaching 6 min 38° C. 30 L
Fixing 4 min 38° C. 29 L
2nd washing 4 min 38° C. 35 L
Final rinsing 1 min 25° C. 19 L

The compositions of the processing solutions were as follows.
< 1st developer>
Nitrilo-N,N,N-trimethylene 1.5 g
phosphonic acid ·
pentasodium salt
Diethylenetriamine 2.0 g
pentaacetic acid ·
pentasodium salt
Sodium sulfite 30 g
Hydroquinone potassium 20 g
monosulfonate
Potassium carbonate 15 g
Potassium bicarbonate 12 g
1-phenyl-4-methyl-4- 2.5 g
hydroxymethyl-3-
pyrazolidone
Potassium bromide 2.5 g
Potassium thiocyanate 1.2 g
Potassium iodide 2.0 mg
Diethyleneglycol 13 g
Water to make 1,000 mL
pH 9.60

The pH was adjusted by sulfuric acid or potassium hydroxide.


< Reversal solution>
Nitrilo-N,N,N-trimethylene 3.0 g
phosphonic acid
pentasodium salt
Stannous chloride dihydrate 1.0 g
p-aminophenol 0.1 g
Sodium hydroxide 8 g
Glacial acetic acid 15 mL
Water to make 1,000 mL
pH 6.00

The pH was adjusted by acetic acid or sodium hydroxide.


< Color developer>
Nitrilo-N,N,N-trimethylene 2.0 g
phosphonic acid ·
pentasodium salt
Sodium sulfite 7.0 g
Trisodium phosphate · 36 g
dodecahydrate
Potassium bromide 1.0 g
Potassium iodide 90 mg
Sodium hydroxide 12.0 g
Citrazinic acid 0.5 g
N-ethyl-N-(ß-methanesulfon 10 g
amidoethyl)-3-methyl-4
aminoaniline · 3/2 sulfuric
acid · monohydrate (CD3)
3,6-dithiaoctane-1,8-diol 1.0 g
Water to make 1,000 mL
pH 11.80

The pH was adjusted by sulfuric acid or potassium hydroxide.


< Pre-bleaching solution>
Ethylenediaminetetraacetic 8.0 g
acid · disodium salt ·
dihydrate
Sodium sulfite 6.0 g
1-thioglycerol 0.4 g
Formaldehyde sodium 30 g
bisulfite adduct
Water to make 1,000 mL
pH 6.30

The pH was adjusted by acetic acid or sodium hydroxide.


< Bleaching solution>
Ethylenediaminetetraacetic 2.0 g
acid·disodium salt·
dihydrate
Ethylenediaminetetraacetic 120 g
acid·Fe(III)·ammonium·
dihydrate
Potassium bromide 100 g
Ammonium nitrate 10 g
Water to make 1,000 mL
pH 5.70

The pH was adjusted by nitric acid or sodium hydroxide.


< Fixing solution>
Ammonium thiosulfate 80 g
Sodium sulfite 5.0 g
Sodium bisulfite 5.0 g
Water to make 1,000 mL
pH 6.60

The pH was adjusted by acetic acid or ammonia water.


< Stabilizer>
1,2-benzoisothiazoline-3-one 0.02 g
Polyoxyethylene-p-monononyl 0.3 g
phenylether (note: Nonoxynol, a detergent)
(average polymerization degree = 10)
Polymaleic acid 0.1 g
(average molecular weight = 2,000)
Water to make 1,000 mL
pH 7.0