E-6 process

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The E-6 process (often abbreviated to just E-6) is a process for developing Ektachrome, Fujichrome, and other color reversal (slide) photographic film.

Unlike some other color reversal processes (such as Kodachrome K-14) that produce positive transparencies, E-6 process can be done manually by amateurs with the same equipment that is used for processing black and white negative film or C-41 color negative film. However, unlike black and white developing, the process is very temperature intolerant; and the use of a tempered water bath to stabilize the temperature at 100.0°F is recommended to maintain process tolerances, especially for the critical first developer bath.

By contrast, the K-14 process and older Kodachrome processes are much more complex than E-6, and is currently performed in only one specialized processing plant world-wide (Dwaynes Photo Service in Parsons, Kansas); with all other Kodachrome cine and K-Lab processors shut down and decommissioned.

E-6 generally replaced the E-3 and E-4 processes in 1976. The older E-3 process used light for reversal, and produced transparencies that faded more quickly. The E-4 process used chemicals that are environmentally unfriendly and the highly toxic reversal agent Tertiary Butyl-Amine Borane (TBAB).

There are two families of E-6 processing chemistries. The original and standard that is used in commercial labs employs a six chemical step process. The 'hobby' type chemistry kits (such as sold by Tetenal) use three chemical steps, combining the first developer and fogging bath solutions, and the pre-bleach, bleach and fixer bath solutions, with a discrete color developer step in between. However, the three step process suffers from poor process control (i.e. color shifts and color crossover), especially due to insufficient bleaching and/or fixing in the bleach-fixer ("blix") mixture. Rinses, washes, stop baths and stabilizer/final rinse (the final step of the process) are not counted in the counting of steps described below.

[edit] Conventional six step processing

The basic steps for developing color transparency films using process E6 are as follows. For more details, please see Replenishment and the Kodak process E6 processing manual Z-119.

• First developer, 6:00 @ 100.0°F. This uses a metol -- hydroquinone (MQ) black & white developer.
• First wash (water stop bath), 2:00 @ 100°F. Originally this step used an acetic acid stop bath, but was replaced with a water-only bath.
• Reversal (fogging) bath, 2:00 @ 96-103°F. For troubleshooting an out-of-control process, the reversal step can be done with 800 footcandle-seconds of light.
• Color developer, 6:00 @ 96-103°F. This is a process-to-completion step. Variation in color developer pH causes color shifts on the green-magenta axis with Kodak E100G & E100GX and Fujichrome films and on the yellow-blue axis with older Ektachrome films.
• Pre-bleach, 2:00 @ 90-103°F. This bath was previously called "conditioner", but was re-named pre-bleach in the mid 1990's to reflect a major change in removing the formaldehyde in the final rinse. The pre-bleach bath relies on carry-over of the color developer (i.e. no wash step) to function properly.
• Bleach, 6:00 @ 92-103°F. This is a process-to-completion step, and relies on carry-over of pre-bleach to "kick off" the bleach. Kodak has a recipe which uses a higher concentration of bleach and a 4:00 time but with process volumes declining this is uneconomical.
• Optional: Wash step, which rinses off the bleach and extends the life of the fixer bath. This wash step is recommended for rotary tube, sink line and other low volume processing.
• Fixer: 4:00 @ 92-103°F. This is a process-to-completion step.
• Optional: Second fixing stage using fresh fixer. Please see Why two step fixing is a Really Good Thing, which explains how the archival properties of film and paper are greatly improved using a second fixing stage in a reverse cascade.
• Final wash: 4:00 @ 92-103°F.
• Final rinse: 1:00 @ 80-103°F. Up until the mid 1990's, the final rinse was called a stabilizer bath, since it contained formaldehyde. Currently, the final rinse uses a Photo-Flo-style surfactant, and miconazole, an anti-fungal agent.
• Drying in a dust-free environment.

[edit] Three step processing

1. Pre-warm
2. First developer and reversal
3. First wash
4. Color developer
5. Second wash
6. Bleach-Fix
7. Wash
8. Stabilizer (final rinse)

[edit] Solutions for a three step process

Ingredient Amount First developer Sodium hexametaphosphate (Calgon) 2.0 g Sodium sulphite, anhydrous 39.0 g Potassium carbonate, anhydrous 14.0 g Sodium bicarbonate 12.0 g Phenidone 0.6 g Hydroquinone 6.0 g Sodium bromide 2.2 g Sodium thiocyanate 1.0 g Sodium hydroxide 3.3 g Potassium iodide, 0.1% solution 4.5 ml Water to 1.0 litre Stop bath 1 Sodium acetate, anhydrous 30.0 g Acetic acid, glacial 6.0 ml Water to 1.0 litre Colour developer Sodium hexametaphosphate (Calgon) 2.0 g Trisodium phosphate crystals 36.0 g Sodium hydroxide 3.0 g Sodium sulphite, anhydrous 4.5 g Sodium bromide 0.65 g Potassium iodide 0.1% solution 30 ml Sodium thiocyanate 1.3 g Citrazinic acid 1.25 g CD3 11.0 g Water to 1.0 litre

Ingredient Amount Stop bath 2 As for Stop Bath 1, but do NOT interchange them after use Bleach Potassium ferricyanide 80.0 g Potassium bromide 20.0 g Disodium phosphate, anhydrous 12.0 g Acetic acid, glacial 5.0 ml Water to 1.0 litre Fixer Sodium thiosulfate, crystals or anhydrous 200.0 g 125.0 g Sodium sulphite, anhydrous 5.0 g Sodium metabisulphite 0.5 g Water to 1.0 litre Stabiliser (optional) Formaldehyde, 40% 5.0 ml Wetting agent 1.0 ml Water to 1.0 litre

[edit] External links

[edit] Official Kodak information

• Kodak process E6 Ektachrome (color transparency) processing manual Z-119
• Kodak process E6 Q-LAB processing manual Z-6 (more details than processing manual Z119 above)
• Kodak Ektachrome E100G & E100GX film data sheet

[edit] Official Fujifilm & Fuji-Hunt information

• FujiFilm USA Product Bulletin Library technical data sheets

[edit] Other resources

• E-6 process by Claudio Bonavolta

[edit] Processing of older Ektachrome films

Processes E-2, E-3, and E-4

• Process C-22 UK and Europe
• Film Rescue USA and Canada
• Rocky Mountain USA
• E-6 Ektachrome DIY processing super-8