I must add nowt hat this is in no way
knocking the home brew worker! I can fully appreciate their knowledge and
keeness to work from the basics and, over the years they have produced
excellent transparencies. But please read on and take in what Roy says in
his article, especially regarding “Bleach’ and the way that many of
you may have carried over the working methods of previous formulae, into
the newer one, which may not require the same methods. In turn I have
avoided Chemical Reversal and Blix with the same distain, but previous
experience has now left me with much confidence in these baths and the
welcome cutting out of many stages in processing such as washes and the
number of bottles required...... Now over to Roy (Salmons)..
First of all,
thanks to Ron Knowles for the publicity. I’m afraid that Ron is a little
out of touch, practically all well known suppliers of E6 kits now issue.a
3-bath version, and nothing else: Paterson, Phototechnology,
Unicolor etc. Agfa still do a four bath kit, while the Photoworld
Traditional kit copies exactly the Kodak official 7 bath kit. It is to
this latter to which we must first turn. Since Kodak originated the E6
process we must assume that they researched the procedure sufficiently to
give the best possible results from their film. What do we find!
Surprise, Surprise! NO STOP BATHS in the entire seven chemical
baths. Here’s the official programme.
First Developer 2.
Wash
3.
Reversal bath
4
Colour Developer
5.
Conditioner
6.
Bleach
7.
Fix.
8.
Wash
9.
Stabilise
10.
Dry.
Note the absence of intermediate washes except stage two.
Confirmed brew-it-yourselfers like Ron,
have done really little more than adapt the old CR50 process for the new
emulsions. They have done it extremely well, I admit, but that doesn’t
mean that there is no other way of working, nor in fact that theirs is the
best method. Just different. I can tell Ron straight away where his
magenta slides went wrong. He used a bleach bath containing Potassium
Ferricyanide. Problem solved. But to extend a bit for the benefit of those
who don’t know what we are on about.
The Pot. Fern/Pot. Bromide type of
bleach - going back to the
days of CR50 and beyond - is a very efficient way of converting the
developed silver image back to silver halide for subsequent removal in the
Fixer, But this formula does have two great disadvantages. One, you cant
use it in a combined bleach-fix bath, and two, it reacts with the colour
developing agent to produce a BRIGHT PINK DYE which cannot subsequently be
removed.
To avoid the formation of the
magenta menace you have to make sure that after the Colour development all
traces of the colour developer are removed from the film emulsion. This
is most commonly done with prolonged washing, often coupled with a Stop
bath. So far as Ron’s own brews are concerned he is perfectly correct in
insisting on the use of the stop bath. BUT ONLY BECAUSE OF THE USE OF POT.
FERRI IN THE BLEACH BATH. So the big secret that Ron wishes me to divulge
is, in fact, no secret at all.
Let me - at risk of boring those who
gave up Pot. Fern. long ago -
tell all. Don’t use Potassium Ferricyanide in your bleach bath, and you
can forget all about stop baths. There, All is revealed. Well nearly all.
I haven’t yet tolled you what to use instead, But I will. It’s not
new- I used it over a quarter of a century ago in a Paycolor
‘Universal’ brew. Now those of you who know me will gasp at the tender
age I must have been all that time ago. (even my daughter now sends me
birthday cards saying “Not 29 AGAIN?.”) All right, enough of the,
nonsense. To avoid any danger. of magenta staining use a bleach bath
containing a complex salt EDTA NaFe (known under various names including
Suquenstrene Iron Complex). It used to be more expensive than Pot, Fern
but I think the gap has closed now and the difference in price is
marginal.
Either this salt or the Ammonia
variation of it is the ingredient in the official Kodak E6 bleach, It is
also used in virtually every other brand of E6 kit on the market today -
including the top value 7 bath PhotoWorld kit And NO STOP BATHS.
And
just in case there is anyone out there who might think that I’d be daft
enough to issue a processing kit that didn’t give top class results,
I’ll give a run down on the three bath process as used in the three bath
kit as used in the Photoworid New Three Bath Kit (and presumably all the
other makes follow the same procedure). First comes the first developer,
which produces the usual black and white negative image. This is followed
by a wash to get rid of the first developers from the emulsion. The second
bath is a combined chemical
reversal and colour developer. Remember this is not a
new idea - E4 used it
before E6 became available. Well this is similar, except the reversal part
of the bath is far less toxic than was the case with E4’s TBAB
chemical.
Then follows a bleach-fix bath, requiring initial vigorous agitation,
and finally washing completes the process. And as the Bleach-fix contains
no potassium ferricyanide but EDTA NaFe there is no danger of any magenta
staining; just perfect slides.
Naughty Ron - bet you knew it all the time!