FRANK'S FORMULA FOR E6 SUCCESS
Frank W. White. Area 13.
Having read considerably in the photographic press, C.R.C. News and Books, I have come to the conclusion that Success will only come to those who are prepared to invest in suitable equipment, time and perseverance together with a certain amount of chemical laboratory experience. Today the photographic press ignore any processing. The state of the art is such, like electronics, it is beyond the capability of the average person and like television they want instant results, nobody is prepared to work to achieve it, except the chosen few, and the Japanese have successfully exploited the camera and lens field and the Yellow God, the chemical process and now I believe the japanese have a suitable back whereby a piece of oxide tape can be made to record a still picture, and this can be "played" back via a suitable piece of apparatus on a television screen
Where does this lead us, and what do I mean when I say "Formula for E6 Success"? First and foremost, the E6 process was developed by Kodak to reduce the processing time in the processing plants of America, and secondly to reduce the quantity of water used and to reduce the cost of processing of effluent in the States under their ecology legislation. It had to be better than E2 and E6, and E5 was a failure. The initial E6 used some horrid chemicals and was not very popular with many firms. The latest E6 process is tolerable, exept in my opinion the Reversal chemicals, both Stannous Chloride and Propionic acid are carcinogenic, but these can be avoided quite simply.
Now let us look at the facts, the temperature is elevated, the time in the first developer is critical, the reversal process must be complete, the colour developer must act in such a manner with the developed silver grains to produce suitable dyes to record the colours of scenes originally photographed. Next the redundant silver must be removed and finally the emulsion must be fixed and the dyes stabilised.
It seems, therefore, that as amateurs, "brewing" or more aptly put, compounding out the colour developer and bleach are where our probems lay, although there are other areas where errors can creep in.
Let us examine the first developer; this Developer is no more than a standard Black and White developer, but it must be capable of penetrating the three layers of hardened gelatine emulsion to produce the silver halides, to this end the temperature has to be raised to ensure that the innermost layer is adequately developed and the outermost layer restrained. The restraining effect is most noticeable in the blue-sensitive layer, and if the bromide is too low in concentrate there can be considerable fog and subsequently lack of yellow in the final image. The timing and the temperature must be done with as much accuracy as compounding the formula. Fluctuations of the first developer pH can result in variations in the colour balance of the subject matter of the exposures. First Developer pH chiefly affects it`s activity, raising or lowering it`s reducing power. and resulting in increase or reduction in the speed of development.
However, it is the writer's opinion that the official processing kits and in particular "Chrome Six" contain Potassium hydroquinone monosulphonate at the rate of 20gms/Litre. (I was quoted by Rayco £23.00/Kg or £9.06 per 100gms in October 1986, being unable to trace a supplier until I received Ubi-chem's catalogue). What improvement this gives I have no idea, but of course if this is not an inflated cost it could explain the high cost of manufacturing kits. However, I digress.
Now, if reversal is carried out by exposure to light, the reversal bath must be replaced with a Stop bath, consisting of 2% acid for 1 min. at 38C followed by a rinse for the same time and temperature. Initially this must be carried out in the dark, i.e. the tank lid must be closed, but since I use changes of water and not running water for the last three changes, the tank is opened, and the last 20-25 ml in the tank are drained away. I then mount the film in it`s reel on a glass rod, and give five flashes per side of the reel, without removing the film, with my Vivitar flash gun (Mains driven) and then proceed with the Colour developer. I have no experience of chemical fogging, although I do have the where-with-all to carry out the process. In fact the light reversal process is so quick and easy I just do not bother with the chemical process. It only takes about 20-30 seconds from start to finish.
Now for the Colour Developer. Although this step is basically the same as the previous colour processes, it is here that the greatest changes have been made. The essential factor is a reducing agent of complex formula, with modifying ingredients, which may be either simple of virtually complex.
The colour developer is activated by alkali such as carbonate, but a few require the higher degree of alkalinity which can only be obtained with Caustic Soda (NAOH); Bromide and Sulphite, as restrainer and preservative in low concentrations, especially Sulphite which can have a depressing effect on dye formation.
To intensify the dyes, to prevent fogging, and to avoid premature exhaustion of the developer, unusual re-agents are used. Some are unobtainable, and others are covered by patents, viz Cibachrome Bleach and developer. Variations in the pH especially if too low gives a blue cast, if too high a pH, a yellow cast.
If the colour developer is too dilute, a magenta cast, how, you may wonder, does this come about!; it means either that too,many films have been put through, or one has been processed and then put away until the next time, i.e. the developer has deteriorated on standing.
My process uses CD4, this was originally used in the C41 process. It is more vigorous than CD3, allows a slightly shorter processing time and has a better ability to penetrate into the emulsion layers than CD3.
Next comes a Conditioning bath, a Clearing bath or Stop bath depending on the bleach being used, this is really a muddle, and failure to understand what is going on, using the wrong bath will ruin as film, and many hours work.
It is imperative that all traces of the colour developer are removed before proceeding to the bleach stage, especially if a Potassium Ferricyanide bath is to be used. Hence not only are various formulations made up, most of which contain acid sulphites or buffered solutions of acetic acid, but the subsequent wash must never be skimped, otherwise stains will result, these can be seen in the highlights, i.e. where maximum silver was developed in the first developer and if you think you have a magenta cast, in reality it is a pink stain and it cannot be removed. (A little known fact, Kodak Bath RG1 0.5% ferricyanide is used to regenerate cyan and magenta if they have been bleached too far).
Coming to the bleach, I have not used tri-ferric salt of ammonium EDTA, I have yet to fully decide if any improvement in the quality will result, there 14.
are snags with using it and the greatest problem using the ferric EDTA complex is the formation of colourless leuco dyes, and unless carefully controlled the amount of cyan dye generated is less than it should be and the red densities are accordingly too low.
"Fixing": the exact composition of the bath is not really important. I have not noticed the effect of the various compositions but generally keep the pH between 6.6-7.0, so it is quite wide, from slightly acid to neutral.
Stabilisation
The final wash carried out must be thorough to remove all traces of fixers and there is no real advantage in extending the time beyond the specified time. The stabiliser contains formaldehyde and a wetting agent and without it one or more dyes may lose intensity with the passing of time.
Finally, drying. Do not hurry it up, because it may collect particles of dust which will become imbedded in the emulsion and cannot be removed.
Processing Equipment
1. Thermometer: These want to be accurately calibrated, a certified B.S. one is best. Do not use a spirit one under any circumstances, the accuracy demanded of the process preludes their use.
I have three certified B.S. mercury thermometers and an electronic digital one and they read within 0.1% of each other. Two mercury thermometers have large bulbs, and one has a small bulb. This one is the best for small volumes as the small amount of mercury removes very little heat from the solution and stabilises quicker. ("Help the aged" supply an electronic digital thermometer for £9.95 plus postage).
2. Timing Apparatus Accurate timing of steps is essential, and a laboratory re-setable clock is used, a stop watch is also suitable, a digital clock is unsuitable and so is an ordinary analogue face clock even though it may have a sweep second hand.
3. Measuring Cylinders and Pipettes: I normally make up the 250ml solution, so I use 400ml graduated beakers, with the pipettes I use a suction pump, although I have 5 and 10ml pipettes, I find the 5ml one is the most useful, as once can measure to ¬ml easily. A 25ml measuring cylinder is rarely used.
4. An Immersion Heater: Initially I had two for raising the temperature of the water and certain solutions, this has been discarded in favour of (a) temperature controlled water bath using a UNO heater and thermostat. It is suitable for up to about 4 to 6 Litres of water. To raise the temperature of water I use an electric plastic jug kettle less the liquid, this is excellent.
5. For Reversal of Film: A glass rod is held in a clamp and a mains driven Vivitar 2500 flashgun is used for re-exposure.
6. Scales and Weights: The first scales bought were similar to a letter balance but only had an accuracy of +/- 1 gram. Adequate for large quantities of developer or fixer in black and white, but useless with small quantities unless % solutions were used.
After refusal by the local Education Authority to sell redundant balances, and, exhorbitant prices at school auctions, I purchased a set of Russian scales and weights, and with these I can weigh to +/- 5 mg. with ease.
7. Finally: I thought I would work without a pH meter, I also contemplated making my own, the cost of the whole probe was not cost affective. Initially, I took the view that formula must be right, provided I weighed correctly, checked the temperature as being reasonable then the pH should come out right. It was the missing factor, I discovered that B.D.H. could supply very close range pH papers, albeit they were expensive, they were a quick and rough guide to within 0.5 of the value. Surely I thought, that should be good enough! During all this period I was developing E6 films of various sorts and was disappointed with the results and was resigned to having them processed commercially. Talking to the people ar "ARC" Processors in London, I was amazed to learn that "no" they did not use a pH meter, but accurately controlled the specific gravity of their solutions and used a densitometer every fourth film and adjusted the sp. g. according to the densitometer reading. Since the sp. g. is a measure of the weight or specific density of the solutions, something new in photographic processing, it obviously bears some relation to the pH of the solution, I decided that I could not process any E6 film successfully until I had done something about the problem. I first saw the C.P. pH meter in a Garden Centre sometime last June, but honestly thought it cannot possibly be any good and decided against it. I next saw it at the Area 13 meeting and read the report produced by Major & Rita Pearle, so when Margery Meadows offered to purchase a quantity in bulk I arranged a purchase. I must sat it was the wisest thing I did. It now tells me if I have made a mistake in weighing, if my chemicals are off and last but not least, I can control the pH of solutions to the values stated in the literature. No honest weigher and mixer should be without one. It is very accurate and not only good value for money but removes a nagging doubt.
So therefore one has had to build up a complete set of equipment, to process one`s own films, I can do it economically, I know I will have fresh solutions, I could use dry prepared mixtures, but what if I only have one film, it is not worth it at the prices charged for processing, or purchasing of a kit. I can process the film to my own taste, I can rate the film what I please if I decide to underexpose, or overexpose I can compensate in the developing, so it has great advantages.
Initially, I had problems with staining after the colour developer, the information given with the faults is rather sketchy and tends to be ambiguous. This I finally cured after using a different Stop bath and washing before using a ferricyanide bleach.
Formulae: These formulations have given results of comparable quality to those obtained by the use of the manufacturer`s chemistry.
First Developer. pH 9.7 +/- 0.1
Calgon ........................................................ 2 .0 gms.
Sodium Sulphite (Anhyd) ...................... 15.0 gms.
Sodium carbonate (Anhyd) ..................... 9.6 gms.
Hydroquinone .......................................... 6.0 gms.
Phenidone ................................................. 0.4 gms.
Sodium Thiocyanate 20% Sol. ................. 8.0 mls.
Potassium Bromide 20% Sol. ................... 10.0 mls.
Potassium Iodide 1% Sol. ........................ 10.0 mls.
Water to .................................................... 1000 mls.
The water is boiled in an
electric kettle for two minutes and then allowed to cool.
The pH was found to be 7.8/8.2 depending on ambient and water
temperature.
First Stop bath.
Acetic acid ............................................... 20.0 mls.
Water to .................................................. 1000 mls.Colour Developer. pH 11.6 - 11.7
EDTA No. .......................................................... 43.0 gms.
Tri-sodium phosphate 12H20 ......................... 40.0 gms.
Sodium Sulphate (Anhyd) ................................ 4.0 gms.
Potassium Bromide 20% Sol. ............................. 2.5 mls.
Potassium Iodide 1% Sol. ................................... 3.0 mls.
Citrazinic acid ..................................................... 1.2 gms.
Hydroxylamine hydrochloride 5% Sol. ............. 7.5 mls.
CD 4 ...................................................................... 7 5 gms.
Water (De-ionised) to ...................................... 1000 mls.
CD 3 can be used at the rate of 12.0 gms per 1000 mls.Second Stop Bath.
Sodium Acetate (Anhyd) .......... 30.0 gms.
Acetic acid ...................................... 6.0 mls.
Water to ........................................ 1000 mls.Bleach. Ph 6.7 - 6.9
Potassium Ferricyanide (XTALS) ......... 100.0 gms.
Potassium bromide ................................... 35.0 gms.
Di-sodium hydrogen phosphate 12H20 20.0 gms.
Water to ..................................................... 1000 mls.Fixer. pH 6.6 - 6.7
Ammonium thiosulphate (XTALS) ............ 70.0 gms.
Sodium metabisulphite (XTALS) ................ 10.1 gms.
Sodium sulphite (Anhyd) .............................. 7.0 gms.
Water to .......................................................... 1000 mls.Stabiliser
Formaldehyde 35 - 40% Sol. ............. 30 mls
Wetting agent 10% Sol. .............. 10.0 mls.
Water to ........................................ 1000 mls.
I use Durst Tanks; these are kept scrupulously clean, I process one transparent reel in 250 ml tank and 2 reels of 35mm film if necessary in 400 ml tank, but I can make up 250 mls and store this volume of liquid better than 400 mls since this is a none standard bottle size.
I do not recommend the use of stainless steel tanks since some chemicals will react with the stainless steel, and the metal reel is totally unsuitable for my method of re-exposure. I have tried the Paterson tank, but the modern tank is very clumsy and uses a large volume of solution, and the translucent reel is unsuitable for my method of re-exposure.
Procedure.
All solutions should be stabilised in a water bath, temperature of approximately 40C. I use the technique of allowing the temperature in the tank to drift to about 38C whilst maintaining the bath temperature of 40C. I check the initial temperature of the First Developer and this is usually about 39«C. I then check the temperature at the end of each process as a matter of routine to find that it is 38C or slightly less, this procedure is essential since I cannot check the temperature in the Durst tank with a film in it, and there is need to allow for changes in the rate of cooling.
Agitation, this is very important. An initial agitation of 15 seconds is given during which the tank is tapped on a hard surface to dispel any bubbles of air that may be trapped in the spiral against the emulsion surface. Then every 30 seconds I give two inversions slowly.
The times given below include the time needed to empty the tank. The 250ml Durst empties in approximately 5 seconds and the 400ml tank in about 10 seconds.
First development 7 minutes 38C
First Stop 2 minutes 38C
Wash minimum of 6 changes of 250ml of water at 38C
Reversal electronic flash exposures through water at 38C
Colour Developer 6 minutes 37 - 39C
Second Stop 2 minutes 37 - 38C
Wash minimum of 6 changes of 250ml of water at 38C
Bleach 5 minutes 37 - 39C
Wash minimum of 6 changes of 250ml of water at 38C
Fixer 4 minutes 37 - 39C
Wash minimum of 8 changes of 250ml of water at 38C
Stabiliser 1 minute 37 - 39C
Life of solutions.
For each subsequent film in the First Developer I give and extra 15 seconds to a maximum of 3 x 36 exposure 35mm films for each 250ml solution. This gives at least 12 x 36 exposures/Litre. The first Stop is used twice only and then discarded. The Colour Developer is used similarly as the First Developer, i.e. 3 x 36 exposures, i.e. 12 x 36 exposures/Litre. The second Stop is used fresh and once only and then discarded. Bleach and Fixer have similar capacities as First & Colour Developers and are discarded after three uses or three months.
Finally in conclusion, there will no doubt be further changes in film emulsions but whether we will be able to accommodate these changes I have no idea. Certainly a new-comer to the hobby is going to be faced with an outlay for equipment and chemicals.
A very persistent and enquiring mind as well as a profound knowledge of the subject, especially as the manufacturers patent their processes and chemicals only become available in industrial quantities.
Certainly I have carried out a lot of reading and researched a lot of processes, that have now become only one E6. I can now achieve as good as the results that I achieved with the old 50S Agfa colour process. I wish everybody success in the future and hope no further change will be made that will have to stop using my existing equipment.
ADDENDUM.
1. ROOM TEMP.
DEVELOPER TEMP C
+/- 0.2.
17C
45.0C
18C
44.5C
19C
44.0C
20C
43.5C
21C
43.0C
2. EXPOSURE ADJUSTMENT TO FIRST DEV. TIME.
2 stops under + 5 1/2 minutes
1 stop under + 2 minutes
Normal None
1 stop over - 2 minutes