Re: Increasing Carbon speed.

From: Bill William ^lt;>
Date: 12/17/04-09:12:47 AM Z
Message-id: <>

> > It depends on the initial emulsion whether it is
> > incredible or not. I doubt you would get that much
> > increase with every emulsion.

I do see same degree of speed increase with a fast plate
emulsion. This emulsion is precipitated
 very slowly at 70C and ripened, desalted and
> digested for high
> sensitivity. This is sulfur plus gold sensitised.

That proves nothing and detracts from the truth of what I
wrote... zero.

It is perfectly possible to sulfur+gold sensitise in such
a way the emulsion MIGHT appear to be giving you 2 stops
more with a dopant. Without knowing the actual S+Au only
sensitivity, who can judge how significant the increase
you are seeing is?

 Anyway, it is almost meaningless to describe
> results
> > between emulsions of differing crystal size and
> habit.

> Then you shouldn't ask about dopants.

Why not? It is a valid question! It just has to be
accompanied by a description of crystal size however to be
of much value.

> > Well, there must be some inconsistency in your
> > procedure... when things really are the same, it
> should be
> > as predictable as clockwork.

What I said is
> that the result
> varies depending on the iodide content and time of
> addition of iodide.

I thought you said: "when it works..."

> I just wanted a
> simplified procedure to make very practical emulsion
> within one hour
> so that I can make a batch with customised contrast
> every session.

To my ears this is very strange... why would you want to
do such a thing? This one I really don't get.

I guess its ok thogh.

But I think a better aproach would be to improve the
quality and consistancy of one's shooting at the initial
stages rather than do a quick fix up job in the

> These emulsions compare well with commercial
> multigrade enlarging
> papers in terms of speed.

Sorry, I don't get it...

How fast did you say your S+Au sensitised chloride
emulsion with and without cerium and the other nameless
dopant that is not cadmium which is also not a rare earth

This uses another, much more common metal ion complex,
not rare earth.


What possible reason do you have for cloaking the name of
a commonly used dopant?

> > I am not sure you have to resort to using such
> unusual or
> > left-field methods to attain suitable results.
> So whatever you don't use is unusual and left-field
> method?

No, of course not!
That is only the case when I am using traditional

Do YOU consider the use of cerium doping

(Mind you, I am not saying it isn't, I am just asking if
you are doing what you consider to be an established
standard procedure by photographic paper manufacturers,
you were talking about paper emulsion, right?)

There are a lot of documents dealing with cerium and the
phototherographic process... cerium is even used in
photochromic glass... I just haven't read the one you are
digging into...

Do I have to hunt the mouse?

I don't think it is all that common...
but maybe it is, and I just don'tknow about it...
but your own comments see to imply you are trying
something new... if so thats good.

But you can't have it both ways....

 Out of many
> enlarging papers that were discontinued in the past
> decade, several
> chlorobromide emulsions had to be discontinued
> because good quality
> could not be obtained without cadmium doping.

What proof of this do you have?
As I understand it cadmium was NOT in general use in cold
to neutral toned chorobromide emulsions.

Do you know of any PROOF this is not the case?
Which paper do you claim was a victem of this regulation?

(Cadmium was easily replaced in lith films, BTW.)

> Anyway, if you don't want to describe your
> emulsions, that's fine.
> I got enough information for what I need.

I wrote you:
Send me your address and next time I make a batch I will
send you a sample.

Is all you want a bunch of verbal hype?
To what end?

I would much rather have a single sample of your emulsion
in my hands than to read a 1000 pages of your description
of it!

I just thought you were serious. Guess I was wrong!


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Received on Fri Dec 17 09:13:15 2004

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