From: Campos & Davis Photos (photos@campos-davis.co.uk)
Date: 04/11/00-06:47:31 AM Z
I would be very interested to see that. Could you publish the results
on the web please?
Having tested all the products available in UK I can say that the
variable contrast emulsions performed quite well up to about grade
three, but showed no perceptible increase in contrast beyond that.
There are a number of variable contrast papers on the market in UK
which are not fully variable contrast in the way one would expect.
That is, a discrete increase in contrast in equal proportion when
using a standard set of Ilford filters multigrade filters. Other
filters must be used to achieve a result approaching that of Ilford
multigrade paper and this necessitates increased exposure times. The
results showed that a difference in contrast could not be achieved
between grade 4 and grade 5 using Ilford Multigrade filters, whereas
the difference when using Ilford Multigrade paper between grade 4 and
grade 5 is considerable.
Some liquid emulsions are bottled from the same source as that used to
coat papers. The exact formula for variable contrast emulsion is very
complicated and a closely guarded secret and has not been learnt by
all manufacturers.
Campos & Davis Photos
6 Cranbourne Road
London N10 2BT - UK
Tel: + 44 181 883 8638
Fax: +44 208883 8638
email: photos@campos-davis.co.uk
www.campos-davis.co.uk
----- Original Message -----
From: Judy Seigel <jseigel@panix.com>
To: Campos & Davis Photos <photos@campos-davis.co.uk>
Cc: <alt-photo-process-l@skyway.usask.ca>;
<alt-photo-process-error@skyway.usask.ca>
Sent: 10 April 2000 06:02
Subject: Re: liquid light on eggs
>
>
> On Sun, 9 Apr 2000, Campos & Davis Photos wrote:
>
> > The main problem with most "liquid light" emulsions is that they
are
> > slow and low contrast.
> > I don't see why anyone would want a slower emulsion so long as the
> > contrast was correct. Contrast is a perceived quality which is
subject
> > to a number of variables. An emulsion which is inherently more
> > contrasty can be made less contrasty be various means, but not
visa
> > versa.
>
>
> A number of the commercial emulsions are now Variable Contrast,
including
> the one from Kentmere sold by Silverprint in London and by Luminos
in the
> US. Also Cachet Black Magic is variable contrast. Post-Factory
Issue #3
> has 5 pages about these emulsions, past & present, including test
results,
> etc.
>
> Judy
>
> .................................................................
> | Judy Seigel, Editor >
> | World Journal of Post-Factory Photography > "HOW-TO and WHY"
> | info@post-factory.org >
> | <http://rmp.opusis.com/postfactory/postfactory.html>
> .................................................................
>
>
>
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