Looking for T-Max or Technical pan glass plates

Hi all,
I am currently attempting an experiment that involves bleaching of
negatives. I am new to this sort of process but I understand that this
is typically done with either holographic or plates or photographic
plates with glass substrate. (I am unsure of whether bleaching can be
attempted on your regular acetate or ESTAR-backed films or not) I have
asked our local and other vendors only to learn that Kodak
discontinued these products in 2001.
Do any of you know of other vendors or perhaps a distributor with a
backlog of these plates?
Any plate with resolution near or above 100 lpm will do.

Thanks a lot,
Carlos

C. L?pez wrote:

Hi all,
I am currently attempting an experiment that involves bleaching of
negatives. I am new to this sort of process but I understand that this
is typically done with either holographic or plates or photographic
plates with glass substrate. (I am unsure of whether bleaching can be
attempted on your regular acetate or ESTAR-backed films or not) I have
asked our local and other vendors only to learn that Kodak
discontinued these products in 2001.
Do any of you know of other vendors or perhaps a distributor with a
backlog of these plates?
Any plate with resolution near or above 100 lpm will do.

I can't help you with glass plates, but I can tell you that bleaching
works the same way on acetate or Estar (or printing paper) as it does on
glass. For holography, there are concerns in larger formats about the
rigidity of the medium, but sheet film is what's commonly used now, and
in sizes 4x5 inch or smaller is generally stiff enough as long as the
holography table is adequately vibration isolated.

I assume you're using a bleach based on either potassium permanganate or
potassium dichromate in a dilute sulfuric acid solution; both of these
bleaches are semi-routinely used with sheet and roll film as part of the
process of producing reversal positives, and can be used either after
fixing the film (as with phase holography) or on unfixed film (as for
reversal processing).

T-Max 100 (TMX) is readily available in sheets, either Ready-Load or
conventional, and I think is also available in 8x10. Kodak sells a
reversal kit specifically for TMX that includes a potassium dichromate
bleach and a fogging second developer, which doesn't require a reversal
light exposure. I'm not certain if Tech Pan has ever been sold in
sheets film form, but it will bleach with the same chemicals -- as will
any silver gelatin emulsion.

--
I may be a scwewy wabbit, but I'm not going to Alcatwaz!
-- E. J. Fudd, 1954

Donald Qualls, aka The Silent Observer
Lathe Building Pages http://silent1.home.netcom.com/HomebuiltLathe.htm
Speedway 7x12 Lathe Pages http://silent1.home.netcom.com/my7x12.htm

Opinions expressed are my own -- take them for what they're worth
and don't expect them to be perfect.

T-Max 100 (TMX) is readily available in sheets, either Ready-Load or
conventional, and I think is also available in 8x10. Kodak sells a
reversal kit specifically for TMX that includes a potassium dichromate
bleach and a fogging second developer, which doesn't require a reversal
light exposure. I'm not certain if Tech Pan has ever been sold in
sheets film form, but it will bleach with the same chemicals -- as will
any silver gelatin emulsion.


It is, but it might be a bit expensive for experimenting though ...

Philippe

Philippe Lauwers wrote:
T-Max 100 (TMX) is readily available in sheets, either Ready-Load or
conventional, and I think is also available in 8x10. Kodak sells a
reversal kit specifically for TMX that includes a potassium dichromate
bleach and a fogging second developer, which doesn't require a reversal
light exposure. I'm not certain if Tech Pan has ever been sold in
sheets film form, but it will bleach with the same chemicals -- as will
any silver gelatin emulsion.



It is, but it might be a bit expensive for experimenting though ...

Whatever it costs in sheet film, it's still cheaper than the same
emulsion would be on glass plates. The last plates Kodak produced,
T-Max 100 emulsion in 4x5 size, were discontinued in part because the
market had shrunk beyond the point of practicality -- which was, in
turn, because there was little advantage to glass over sheet film, as
well as because glass costs much more to coat than plastic. Yes,
certainly, glass stays flatter under some conditions -- but you won't
shatter a film sheet if you drop it (you can work around a few
scratches, for the most part). Glass also has to be cut to size before
coating and coated in a straight-line process that takes up a huge
amount of (dark) factory floor space, because it doesn't bend (much) --
the line can have direction changes in it, as would be the case for
other fixed size solid goods, but it can't begin to be as compact as a
line that coats plastic base stock in one (huge) size for cutting to
final dimension after coating and drying.

--
I may be a scwewy wabbit, but I'm not going to Alcatwaz!
-- E. J. Fudd, 1954

Donald Qualls, aka The Silent Observer
Lathe Building Pages http://silent1.home.netcom.com/HomebuiltLathe.htm
Speedway 7x12 Lathe Pages http://silent1.home.netcom.com/my7x12.htm

Opinions expressed are my own -- take them for what they're worth
and don't expect them to be perfect.

Thanks a lot Donald,
I am indeed using a potassium dichromate in a dilute sulfuric acid
solution. I will try bleahcing some 35 mm photoreductions of
computer-generated holograms (my quick-and-dirties) that won't be
missed if I fail. Also, I wasnt aware that reversal could be done as
you mention, I'll et you know how it goes, as I have a panic stock of
T-Max sheets.

Regards,
Carlos


Donald Qualls wrote in message news:yxLuc.26613$eY2.25745@attbi_s02...
Philippe Lauwers wrote:
T-Max 100 (TMX) is readily available in sheets, either Ready-Load or
conventional, and I think is also available in 8x10. Kodak sells a
reversal kit specifically for TMX that includes a potassium dichromate
bleach and a fogging second developer, which doesn't require a reversal
light exposure. I'm not certain if Tech Pan has ever been sold in
sheets film form, but it will bleach with the same chemicals -- as will
any silver gelatin emulsion.



It is, but it might be a bit expensive for experimenting though ...

Whatever it costs in sheet film, it's still cheaper than the same
emulsion would be on glass plates. The last plates Kodak produced,
T-Max 100 emulsion in 4x5 size, were discontinued in part because the
market had shrunk beyond the point of practicality -- which was, in
turn, because there was little advantage to glass over sheet film, as
well as because glass costs much more to coat than plastic. Yes,
certainly, glass stays flatter under some conditions -- but you won't
shatter a film sheet if you drop it (you can work around a few
scratches, for the most part). Glass also has to be cut to size before
coating and coated in a straight-line process that takes up a huge
amount of (dark) factory floor space, because it doesn't bend (much) --
the line can have direction changes in it, as would be the case for
other fixed size solid goods, but it can't begin to be as compact as a
line that coats plastic base stock in one (huge) size for cutting to
final dimension after coating and drying.

--
I may be a scwewy wabbit, but I'm not going to Alcatwaz!
-- E. J. Fudd, 1954

Donald Qualls, aka The Silent Observer
Lathe Building Pages http://silent1.home.netcom.com/HomebuiltLathe.htm
Speedway 7x12 Lathe Pages http://silent1.home.netcom.com/my7x12.htm

Opinions expressed are my own -- take them for what they're worth
and don't expect them to be perfect.

In article yxLuc.26613$eY2.25745@attbi_s02,
Donald Qualls wrote:

Whatever it costs in sheet film, it's still cheaper than the same
emulsion would be on glass plates. The last plates Kodak produced,
T-Max 100 emulsion in 4x5 size, were discontinued in part because the
market had shrunk beyond the point of practicality -- which was, in
turn, because there was little advantage to glass over sheet film, as
well as because glass costs much more to coat than plastic. Yes,

Oh, wow, it's gone even as special-order? I suppose the remaining users
must have switched to vacuum film backs and temperature and humidity
controlled working and storage environments (probably just as cheap
over the long term).

Back around the time when Kodak engaged in their first round of killing
off most of their remaining photo papers (the round before the round
that cost us Kodabromide, which was of course the round before the one
that cost us Elite) I noticed a small boxed item in the Kodak catalog
which pointed out that for a rather large minimum order, Kodak would
coat "any current production emulsion" onto glass plates. I used to
look for that blurb-in-a-box every time I saw the wholesale catalog for
several years; and it was always there, near the listing for the 4x5
TMX plates in fact. I think the last time I looked for it was two or
three years ago.

When you can't pay them enough to make a product that's _always_ been
special-order, then you really know times are changing. :-(

--
Thor Lancelot Simon
But as he knew no bad language, he had called him all the names of common
objects that he could think of, and had screamed: "You lamp! You towel! You
plate!" and so on. --Sigmund Freud

tls said When you can't pay them enough to make a product that's _always_
been special-order, then you really know times are changing. :-(

Yes, it probably would have been so expensive to maintain the line where the
glass plates were made that it was just shut down.

But have no fear, I heard that Kodak has been reading this newsgroup and is
coming out with a new line of caffeine based developers. There would be D-Cafe6
for most film processing needs, Cafetol which would add some ascorbic acid to
give more speed, Cafemax for the Tmax films, Mochacaf for those who want brown
toned negatives, and of course, Cafektol for prints. LOL.


Bernie

Thor Lancelot Simon wrote:


When you can't pay them enough to make a product that's _always_ been
special-order, then you really know times are changing. :-(


I don't know for certain that the ability to special order glass plates
from Kodak is gone -- but if they've stopped offering even a single
emulsion as a stock product, I suspect they've remaindered the equipment
for coating/cutting glass and simply no longer have the capability.

I could be wrong -- but how many thousands of plates, how many tens of
thousands of dollars would be the required order? It's of passing
academic interest to me, since I have two cameras that could use 9x12 cm
glass plates with greater ease than the corresponding size of sheet film...

--
I may be a scwewy wabbit, but I'm not going to Alcatwaz!
-- E. J. Fudd, 1954

Donald Qualls, aka The Silent Observer
Lathe Building Pages http://silent1.home.netcom.com/HomebuiltLathe.htm
Speedway 7x12 Lathe Pages http://silent1.home.netcom.com/my7x12.htm

Opinions expressed are my own -- take them for what they're worth
and don't expect them to be perfect.

Jazztptman wrote:

tls said When you can't pay them enough to make a product that's _always_
been special-order, then you really know times are changing. :-(

Yes, it probably would have been so expensive to maintain the line where the
glass plates were made that it was just shut down.

But have no fear, I heard that Kodak has been reading this newsgroup and is
coming out with a new line of caffeine based developers. There would be D-Cafe6
for most film processing needs, Cafetol which would add some ascorbic acid to
give more speed, Cafemax for the Tmax films, Mochacaf for those who want brown
toned negatives, and of course, Cafektol for prints. LOL.


Bernie

Commercializing coffee based developers isn't as far fetched as all that
-- it would require, first, isolating and/or identifying the developing
agent (most likely candidates at this time are caffeic acid and/or
chlorogenic acid), testing and characterizing those agents with various
film types and in combinations with other agents (since most developers
use two developing agents to combine the features of both, hopefully
while minimizing their drawbacks), setting up an economically viable
method of extracting the developing agent from the very inexpensive
/robusta/ variety beans (some of which are even grown in the continental
United States, most notably in the northern Cascade mountains), and
creating marketing channels for the resulting product.

You'd have to go about it this way, IMO, because nobody is going to be
willing to pay for a packaged developer that takes a half hour to work,
stain-fogs the film, and produces grain the size of golf balls, as
Caffenol does; extracting and concentrating the developing agent, and
incorporating it into a product similar to Pyrocat HD or PMK would let
you sell the effects and the "gosh!" factor without the wait times.

Oh, wait, people do still buy Rodinal, don't they?

--
I may be a scwewy wabbit, but I'm not going to Alcatwaz!
-- E. J. Fudd, 1954

Donald Qualls, aka The Silent Observer
Lathe Building Pages http://silent1.home.netcom.com/HomebuiltLathe.htm
Speedway 7x12 Lathe Pages http://silent1.home.netcom.com/my7x12.htm

Opinions expressed are my own -- take them for what they're worth
and don't expect them to be perfect.

In article Xxuxc.69804$Ly.13436@attbi_s01,
Donald Qualls wrote:
Thor Lancelot Simon wrote:


When you can't pay them enough to make a product that's _always_ been
special-order, then you really know times are changing. :-(


I don't know for certain that the ability to special order glass plates
from Kodak is gone -- but if they've stopped offering even a single
emulsion as a stock product, I suspect they've remaindered the equipment
for coating/cutting glass and simply no longer have the capability.

I could be wrong -- but how many thousands of plates, how many tens of
thousands of dollars would be the required order? It's of passing

I think the old minimum order size was several hundred plates -- which
was still several thousand dollars. I assume they had one or two
remaining production lines, and had worked it out so that you had to
buy enough to cover the incremental cost of diverting a batch of
emulsion to the right line and coating it instead of TMX for a day.

I don't know anything about how volume production of glass plates
worked -- recently or even long ago when they were common items. Do
they coat first, then cut? Or do they cut the glass to size, then coat
each sheet individually? I've had a hellish time getting even coating
out to the edges of glass or ceramic materials I've tried to put emulsion
on myself, so I am somewhat curious what Kodak's production techniques
might have been like.

--
Thor Lancelot Simon
But as he knew no bad language, he had called him all the names of common
objects that he could think of, and had screamed: "You lamp! You towel! You
plate!" and so on. --Sigmund Freud