To Richard K - Perceptol x Microdol

Hello, Richard

Could you comment in the (accepted) data that Perceptol uses an innordinate
ammount of bromide vs Microdol using chloride?

Thanks,

Jorge

"Jorge Omar" wrote in message
...
Hello, Richard

Could you comment in the (accepted) data that Perceptol
uses an innordinate
ammount of bromide vs Microdol using chloride?

Thanks,

Jorge

This is true according to the Material Safty Data Sheet
on the Ilford web site. Microdol-X contains sodium chloride.
Both the chloride and bromide act as fine grain agents in
large amounts. I _think_ I saw an old MSDS for Perceptol
which showed sodium chloride instead of bromide but am not
sure and can't find it in my archived stuff. Haist mentions
sodium chloride in his book but not bromide as a fine grain
agent.
Both developers have proprietary formulas but the
chloride content of Microdol-X is evidently about 20 grams
per liter. There was an earlier version called just
Microdol. I don't know the difference for certain but think
that the X version probably contains something to prevent
dichroic fog. It may be that the bromide in Perceptol also
does this.
Both of these developers work as advertised. 100 T-Max in
full stength Microdol-X is nearly as fine grain as Technical
Pan in Technidol at more than double the speed and is less
fussy about getting normal tonal range.

--
---
Richard Knoppow
Los Angeles, CA, USA

Richard Knoppow wrote:

"Jorge Omar" wrote in message
...

Hello, Richard

Could you comment in the (accepted) data that Perceptol

uses an innordinate

ammount of bromide vs Microdol using chloride?

Thanks,

Jorge


This is true according to the Material Safty Data Sheet
on the Ilford web site. Microdol-X contains sodium chloride.
Both the chloride and bromide act as fine grain agents in
large amounts. I _think_ I saw an old MSDS for Perceptol
which showed sodium chloride instead of bromide but am not
sure and can't find it in my archived stuff. Haist mentions
sodium chloride in his book but not bromide as a fine grain
agent.
Both developers have proprietary formulas but the
chloride content of Microdol-X is evidently about 20 grams
per liter. There was an earlier version called just
Microdol. I don't know the difference for certain but think
that the X version probably contains something to prevent
dichroic fog. It may be that the bromide in Perceptol also
does this.
Both of these developers work as advertised. 100 T-Max in
full stength Microdol-X is nearly as fine grain as Technical
Pan in Technidol at more than double the speed and is less
fussy about getting normal tonal range.


I'm a long way from last using either dev, but from my early experiences
I would have expected bromide or chloride to have acted as mild solvent
agents with a restraining and buffering side-effect, with slightly more
activity from bromide.

Perceptol, which I used for a long time both straight and diluted,
generally had a far superior resistance to aerial oxidation, and with
the long dev times involved for 1+3 user (an extreme) with inversion
agitation, that was technically better. Microdol-X generally proved
slightly harder to dissolve, with more tendency to leaving a small
residue needing filtering, and oxidised more rapidly in stock solution
or diluted working solution.

Kodak used the 'X' suffix to indicate films or processes which were in
line with sensitivity revisions - originally, the X was used to indicate
filmspeeds only. X indicated a speed approximately 32 ISO (pre-war), XX
64, XXX 125. With the changes in calculaton of filmspeeds using density
above fog threshold in the 1950s, X became 64, XX 125 and XXX 250;
further improvements in emulsions meant that Tri-X (XXX) increased to
320 - the rating which still applied to Tri-X Professional into the
1980s - and then 400 for general stock. Panatomic-X remained peculiarly
stuck in the past and was only 32 ASA (ISO) and eventually the whole
concept just got muddled so that no-one really remembers why Tri-X is
called Tri-X! Plus-X, or course, was a little bit faster than X in the
final stages where X meant 100, XX 200 and XXX 400.

Whatever formulation changes were present, the X in Microdol-X probably
got there as part of a marketing concept, and indicated the suitability
of the developer for use with these films - but also implied a retention
of filmspeed. Though Microdol-X (like Perceptol) incurs a loss of around
1/3 to 1/2 the conventionally measured filmspeed unless diluted, it was
in its day far superior to strong solvent developers, which lost half to
2/3rds of available speed and also produced a very low acutance by
destroying micro-contrast. But strong solvent developers were not averse
to using sodium thiosulphate in the dev, being half way to a monobath.

So the X probably just marked the spot... signalled that this was a
fitting companion dev to Panatomic-X, Plus-X and the 'generation X' of
films with their revised sensitivities.

For anyone keen on experiment, in the 1970s I made an ad-hoc special
effect developer by mixing a chromium intensifier bleach with a print
strength MQ developer - in much the same way as a monobath. Negatives
developed in this produce a direct posterization, with a distinct set of
steps, but you have to start the development in a regular developer then
transfer to the combined intensifier/redeveloper mix for the second half
of the dev time.

David
http://www.freelancephotographer.co.uk/
http://www.maxwellplace.demon.co.uk/pandemonium/

Thanks for the explanation, but I still find it intriguing how a
developer works with such a hig ammount of restrainer in it!

Jorge


"Richard Knoppow" wrote in news:VGUuc.18900
:


This is true according to the Material Safty Data Sheet
on the Ilford web site. Microdol-X contains sodium chloride.
Both the chloride and bromide act as fine grain agents in
large amounts. I _think_ I saw an old MSDS for Perceptol
which showed sodium chloride instead of bromide but am not
sure and can't find it in my archived stuff. Haist mentions
sodium chloride in his book but not bromide as a fine grain
agent.
Both developers have proprietary formulas but the
chloride content of Microdol-X is evidently about 20 grams
per liter. There was an earlier version called just
Microdol. I don't know the difference for certain but think
that the X version probably contains something to prevent
dichroic fog. It may be that the bromide in Perceptol also
does this.
Both of these developers work as advertised. 100 T-Max in
full stength Microdol-X is nearly as fine grain as Technical
Pan in Technidol at more than double the speed and is less
fussy about getting normal tonal range.

Jorge Omar wrote in message . 4...
Hello, Richard

Could you comment in the (accepted) data that Perceptol uses an innordinate
ammount of bromide vs Microdol using chloride?

Thanks,

Jorge

I doubt that. Sodium sulphite rather than potassium bromide. The
latter is seldom used at concentrations exceeding 3g/litre in B&W
developers.

"Michael Scarpitti" wrote in
message
om...
Jorge Omar wrote in message
. 4...
Hello, Richard

Could you comment in the (accepted) data that Perceptol
uses an innordinate
ammount of bromide vs Microdol using chloride?

Thanks,

Jorge

I doubt that. Sodium sulphite rather than potassium
bromide. The
latter is seldom used at concentrations exceeding 3g/litre
in B&W
developers.

Have a look at the MSDS. Perceptol contains a very large
amount of bromide. I think the bromide in Perceptol and
chloride in Microdol-X have about the same effect. They slow
down the development. Neither is a halide solvent. There is
considerable solvent action in both developers due to the
high concentration of sulfite and long time of development.
However, the effect of sulfite as a solvent is very often
mis-understood. Sulfite has no significant action on the
developed silver. Nor does it etch the corners off silver
crystals. Rather, it removes a layer from the surface of the
halide crystals and changes the shape of the developed
metallic silver crystals. A small amount of solvent action,
about what is found in D-76, causes an increase in film
speed by exposing more development centers to the developer.
More action, as in Microdol-X, Perceptol, or D-25 when they
are used at full strength can dissolve some of the
development centers, or in other words, destroy some of the
latent image, causing a loss of some speed. When diluted
this effect does not take place. Note that the developing
times for these developers is quite long in comparison to
developers without an extra-fine-grain property. This is the
result of the very low activity of all three. The same thing
is found in the old Para Phenylenediamine developers. PPD is
very low in activity, about the lowest of any practical
developing agent, and it is a halide solvent. A pure PPD
developer may take more than half an hour to develope even
modern film and will lose four or five stops. It does have
finer grain than any other developer but the great speed
loss and generally very low contrast made it impractical.
Most of the practical PPD developers combined it with
something else, often Glycin or Metol. These developers had
no advantage over developers like D-25, Microdol-X, or
Perceptol so fell out of use.
Grant Haise discusses extra-fine-grain developers a
little in his book _Modern Photographic Processing_. This
book, which was long out of print, is available in an
excellent reprint from the author.


--
---
Richard Knoppow
Los Angeles, CA, USA

Richard Knoppow wrote:

Grant Haise discusses extra-fine-grain developers a
little in his book _Modern Photographic Processing_. This
book, which was long out of print, is available in an
excellent reprint from the author.


Do you have an URL or any information about this? I searched
in Google, but found only numerous references to the old
books.

Martin

Martin Jangowski wrote in message ...
Richard Knoppow wrote:

Grant Haise discusses extra-fine-grain developers a
little in his book _Modern Photographic Processing_. This
book, which was long out of print, is available in an
excellent reprint from the author.


Do you have an URL or any information about this? I searched
in Google, but found only numerous references to the old
books.

Martin

Martin, I will post the info when I get home and can look it up. I
got my copy from Grant.

Richard Knoppow
Los Angeles, CA, USA

Martin Jangowski wrote
Richard Knoppow wrote:

Grant Haist discusses extra-fine-grain developers a
little in his book _Modern Photographic Processing_. This
book, which was long out of print, is available in an
excellent reprint from the author.


Do you have an URL or any information about this? I searched
in Google, but found only numerous references to the old
books.

Martin

Available from abebooks.com (great site for used & obscure books).
$490 the set, though.

--
Nicholas O. Lindan, Cleveland, Ohio
Consulting Engineer: Electronics; Informatics; Photonics.
Remove spaces etc. to reply: n o lindan at net com dot com
psst.. want to buy an f-stop timer? nolindan.com/da/fstop/

Originally Posted by Jorge Omar

Hello, Richard

Could you comment in the (accepted) data that Perceptol uses an innordinate
ammount of bromide vs Microdol using chloride?

Thanks,

Jorge

The MSDS that I have for Perceptol is: Metol, Sodium Sulphite, Sodium Chloride and Sodium Tripolyphosphate. This developer may correspond with the Edgar Hyman Microdol substitute formula published in the Film Developing Cookbook by Steven G Anchell and Bill Troop.
The MSDS for Microdol-X reads as Elon/Metol, Sodium Sulphite, Boric Anhydride, Sodium Chloride and Sodium Hexametaphosphate(Calgon).
You can find the components used for many Kodak developers on
www.kodak.com/go/MSDS. and likewise with Ilford chemicals on
www.ilford.com