THAT TO BACCO EFFECT! (OXIDISED!!!)

By Bill Reid & Glyn Willicombe (Area 20)

As explained in my last article on getting the `tobacco` effect, when first using my Jobo processor, I mentioned that I
suspected something wrong with the Reversal bath, but couldn`t quite pin it down and that it could be worth getting
someone to go into it. I also mentioned that Rita Pearle sent me her formula for a Concentrate version of the Reversal
bath which she says works ever time. It was my intention to give this a try but haven`t had the time so far. However
since then Glyn Willicombe kindly sent me a letter explaining his experience with the reversal bath, what causes the
problem and how to solve it:-

"It must be born in mind that Kodak designed their E6 process (procedures as well as chemistry) for use in the
commercial processors with Kodak supplied concentrates, including those for replenishers. White light is too
complicated for such processors, hence the use of a chemical reversal bath. It is not a case that such a bath works
better than white light.

The enemy of the bath is oxidation. Here again this is not a problem with commercial processors as they are designed
to exclude air once the solutions are in and replenishers keep them up to scratch.

I quote from Kodak`s instructions for using rotary - tube processors (I don`t know exactly what these are but
understand spirals are used):-

"Solution Storage Life"

For best results, do not use solutions that have been stored longer than the following times.

Mixed Solutions Tank with Partially Full Floating Covers * Bottles Used or Unused Used. Unused.

Reversal Bath 8 weeks 2 weeks 1 week * Or full stoppered glass bottles.

Bottles must be full (no air space) and glass is specified because many plastics are not air-proof and same applies to
corks and some plastic stoppers.

Use a full bottle as above. However you run into trouble, or a complicated procedure, in topping up the bottle after
use. The mixture for topping must also be in glass without an air space.

If you are going to use more than once (equals one or more films in one tank, or several* films done after each other)
it is advisable to take the following additional precautions:-

Pour bath into, and out of, the tank very slowly, and give gentle agitation, say just a couple of inverts only, to limit the
amount of air that gets into the solution. * I don`t know how many films. The actual bath is not weakened by usage;
it is oxidised by the air, so more gets in each time it is used. Perhaps therefore it is best to play safe by using once only.
Also so far as I`m aware there is no simple test of whether the brew is too oxidised to work properly, short of a test strip.

The answer is, I think, to use a concentrate and use the working solution once only. When I first started on E6 I used
chemical reversal (CR) because I read somewhere that the process was designed by Kodak to use (CR) and white
light exposure should not be used. When the source of my supply of a commercial concentrate ran out (or nearly so),
I tried white light. It worked and I have used it ever since, apart from one or two tests. Incidentally, for one of the tests
I used the concentrate left in the bottle, several months after opening. It worked fine.

Another reason for dropping chemical reversal, was that when the Club published Kodak E6 - based formulae, I tried
them. Some of the results were terrible - reversal not properly done when used more than once. It was not until a few
years later that I uncovered the root cause: Iron present in my tap water supply that accelerated oxidation, so much so
that it failed to work after a couple of days after mixing, or on second use.

Are you sure your tap water doesn`t contain iron/iron products, dissolved in water, iron particles do no harm in reversal
but can of course cause brown spots on final image. Incidentally, I have tried mixing with iron free water and reversal
was fine, but I have not tested for life".

Along with Glyn`s comments, Ron Croad also mentions the possibility that `oxidation` that causes the problem and
Glyn has also added further comments after reading my article in the last newsletter. Glyn writes:-

My comments were in context of using a full tank (or the amount to cover the spiral(s) with inverse agitation. In view of
what you say in your Jobo article, I will amplify my previous comments to cover rotary agitation with the tank only
part full. If you have only sufficient solution in the tank to cover the bottom part of the spiral then only the film in this
bottom part will absorb enough reversal solution to saturate the film - parts of the film will be reversed, others not. Your
method of filling the tank and giving 15 secs. agitation is on the right lines but because of oxidation problems one
inversion, or just 3 or 4 secs. shake would be better. For rotary agitation minimum solution, giving a few turns every
15-20 seconds will do the trick but oxidation will increase to the extent that it would be unwise to use more than once.

To the best of my knowledge, similar considerations apply to the Conditioner as it has the same shelf life as the
reversal solution when it is exposed to air. I suggest that it would be worthwhile to give a test since once use would
waste only a small amount of solution, compared with a full tank and my view top be safe, discard after use.

For normal tank development "Once use" would embrace several films done in the same session. For rotary
development "Once use" means just one film (or several done in the same tank), so the most economical method will
depend on the size, particularly the length, of the tank.

So as far as developers are concerned, a certain quantity of solution is required for each film: if the amount is just
sufficient e.g. 240ml per two films, you quote, then it can be used only once. If you process 4 films (by back-to-back
loading) you will need 500ml. I work to a slightly higher figure - 150ml needed for each film, in practice 4 films in
600*ml, with 300ml into the tank for one film (to cover spiral) or 250ml in my single spiral tanks as this is maximum
capacity after allowing for some air space for efficient agitation. This 250ml or 300ml is used once again, or goes back
into the bottle containing the balance of the 600ml when the next step will be the processing of 2 films with a minimum
of 500ml in the tank.

* The quantity I usually mix these days, as I have found say 100ml goes off before I have exhausted its capacity.

Thanks Glyn. While the Jobo tank instructions state using 240ml, for my latest processing of my holiday films, using a
Jessop PhotoChem 600ml 3-Bath Kit, I split this into two x 300ml lots of 1st. Developer, Colour Developer (includes
Reversal) and Blix. Altogether I got four films (8 x 36exp. in total) processed from each 300ml brew with not a sign of
under reversal in spite of using the brew twice, so is there something in the 3-bath formula that avoids oxidation of the
`reversal`? and what`s the difference in making up the CRC individual Reversal formula?

With 4 further cassettes of film to process I next decided to get a Jessop PhotoChem 300ml, 3 bath kit, but on going
to the shop found they didn`t have any in stock and placed an order for one. After three weeks one became available
and I found that this had a sell-by date of April 97, so being completely fresh! Now, whether this was the cause, or
whether there has been a change to the processing formulae, I don`t know, but what was incredible was the superb
quality of the films. You wouldn`t believe they came from the same bulk roll of Konicachrome as the previous 8
cassettes processed in the older PhotoChem 600ml kit. Is there a connection with the Jessop kits and the fact that the
latest Chrome-Six kits claim to have some technical improvements! Any ideas? Whatever, I can fully recommend the
quality of Jessop`s latest batch of PhotoChem 3 bath kits.

While agreeing with Glyn on the similarity of using the Conditioner bath I have never had any reason to suspect it of not
doing it`s job. As mentioned last time, giving the "Blix" bath plenty of aeration seems to be more important, but Glyn
makes a good point well worth considering.

While on the subject of `aeration` - It puzzles me why it is alright to aerate the "Blix" but we wouldn`t recommend
aerating a single `Fixer` bath! Why isn`t the fixer solution in the `blix` affected when pumping the whole solution full
of air?