Once
again, I have ran into trouble, as Our Editor, Bill has done in the
past, both of us have had trouble processing E6 and I have not nor has
any body really sussed out the problem. At last I am certain I have
cracked it. The trouble lies in the use of small quantities of solution,
rather I should have said in the making up of small volumes of solution.
The
culprit is the Reversal solution. This solution controls lots of things
density, colour & everything you can think of: and the chemical at
the heart of the problem is p-aminophenol. The accuracy of the weighing
in the initial solution, the uniformity of the chemical in the dissolved
solution, and finally the rate of usage as a dissolved chemical in the
final solution i.e. 0.75 ml in 1.5 litres or 0.14 ml in 275 ml. My
calibrated pipette only has 0.5 ml and I am expected to measure 0.15 ml.
So its guesswork hence to ensure reasonable accuracy for the reversal
solution the minimum volumes of Reversal Solution needs to be at least 3
litres. I don't need that volume nor can I handle it. As a practical
result, I have received my working from the following.
(1)
Cost
effectiveness of Reversal Solution.
(a) Loss of
film
- High cost
(b) Quality of developing
- Very variable.
(c) Chemical cost
- expensive.
(2)
Time
(a) To Prepare Solution.
20 - 25 mins.
(b) Processing.
5 - 6 mins.
(3) It is impossible to guarantee the repeatable strength of the
reversal bath due to small quantities f chemicals.
Consequently if the reversal solution is not consistent, the film
developing will not be consistent and hence a failure and costly in
chemicals and a waste of time processing & preparing the solution.
On top of all this is the disappointing result and wondering what went
wrong.
My solution to this problem, is to use light reversal, and I don't mean
hundred watt Bulbs or photofloods & bowls of water. 2 full power
flashes either side of the spool approximately 6 inches. away, and in 15
seconds the job is done. No making up a solution, no temperature check,
no washing, no measurement of pH, no pouring out or in and a saving of
at least 15 minutes in processing time overall, and the result is an
excellent transparency and what is more it is repeatable.
There
is no problem with the quantities of chemicals in the other solutions,
which have larger quantities of chemicals, and hence errors of weighing
& measuring are insignificant on the result.
There
only remains the temperature of the 1st developer. This must be
controlled to the stated value if not the density of the finished slide
will be either too dark or too light.
Lastly
it saves me money and time. I rest my case.