PDA

View Full Version : Panchromatic Dye Matrix Film?



Pages : [1] 2

wildbillbugman
03-28-2012, 12:17 PM
Hello Ron,
I have posted this question on Jim Browning's Die Tranfer Yahoo Group. I figure that you are old enough to remember Dye Tranfer. :D I am thinking about evaluating my current pan emulsion as a pan matrix film. When processed and fully dryed the emulsion shows a feelable positive relief. I Am interested in the dye transfer process. I am wondering if you know what thickness to lay down for a panchro matrix film. I understand that, for ortho matrix film 10-15 microns is required, but a panchro matrix film should be "condiderably thicker"
Bill

holmburgers
03-28-2012, 01:26 PM
Hi Bill, well I'm not Ron of course (though I did stay at a Holiday Inn Express last night..), but I would have to suggest that thickness shouldn't be governed by its spectral sensitivity. One contributing factor to EK Panchro-Matrix being thicker than ortho might be the use of a heavier extinction dye/pigment. If there's a lot of carbon black(?) in there, that could contribute to the thickness.

It seems to me that once it's etched it shouldn't matter whether it started out as panchro or ortho, because having a thin relief is helpful in getting really good flush contact with the matrix & transfer paper.

I'd have to think that investigating PVA's dye imbibition properties would be paramount to coating thickness at this stage. But, whenever I say something like this I end up eating crow when a few more posts come down the line.

FWIW, the Polaroid Vectograph process relied on imbibing dyes to a polyvinyl-alcohol surface, so it will accept dye which is cheery news.

DREW WILEY
03-28-2012, 01:32 PM
I don't know if it was carbon black in there, which would seem purplish black. Pan matrix seemed rather blue-black to my eye, like a dye. Maybe Ctein would know.

wildbillbugman
03-28-2012, 02:26 PM
I'd have to think that investigating PVA's dye imbibition properties would be paramount to coating thickness at this stage. But, whenever I say something like this I end up eating crow when a few more posts come down the line


Holmbuerges. That is the million dollar question.

holmburgers
03-29-2012, 10:21 AM
Bill, for a rough and dirty test you might mix up a batch of RIT dye and make it slightly acidic with acetic-acid or vinegar (maybe 2%ish) and submerge your plates in that.

To my surprise, I was able to make a dye transfer with food coloring and vinegar. At least this test might give you an idea of how PVA reacts to dying.

godspeed!

wildbillbugman
03-29-2012, 10:51 AM
Thanks Holmburgers,
I will try this in about 2 months. I have no time befor my medical time out.

holmburgers
03-29-2012, 11:33 AM
Understood; sending my best for a quick recovery Bill. Warm regards,

Chris

wildbillbugman
03-30-2012, 03:41 PM
Hi Holmburgers and all,
For medical reasons my surgery has been postponed for a couple of months. But I was put under general anesthesia yesterday, so I feel abit off today. But today I tried your suggestion of acidified (red) food color. This was on some older plates that had been fixed and cleered a couple of weeks ago.. One plate that had been hardened with Formalin showed no evidence of red coloring after rinsing under running water. The other plate with no hardener showed red uptake, especialy on the thinner areas. Whether or not this can be made to transfer is another question
I will first make another batch of this emulsion and finish what I need to do with finalization of this formula: Going from 2 alcohol precipitations to only1 and trying another, cheeper dye that has been suggested. Then I will decide where to go from here. I may decide to put the dye transfer on the back burner and go for Jim Brownings sugestion of adding pigment to a panchro emulsion and making a variation of of carbon transfer. Or, I might just make art for a while.
Cheers,
Bill

Photo Engineer
03-30-2012, 03:47 PM
Bill;

IDK the thickness of Matrix or Pan Matrix film. Jim Browning or Ctein might know. As for Carbon Black, it does contain photo active ingredients and must be purified for photographic use. Pan Matrix film used a black dye at one time and Carbon Black at another time. So, the answer is "It depends on the version of product".

PE

T-grain
03-30-2012, 04:58 PM
Bill,
first of all, good luck with your surgery, but I am afraid these PVA matrices simply won't work. The reason is simple: they don't have the amino groups present in the gelatin. The dyes (in their ionic form) are attracted to the protonated amino groups (gelatin), so that's why they are held in place even when you rinse the matrix in acetic acid solution. When you make the contact with the receiving paper, there is a gradient in pH between the matrix and the receiving gelatin, so the dye molecules are driven there. Simply put, the dye molecules are more attracted to a gelatin environment with pH 6 rather than about pH 4 (just to make a long story short).

just my 2 cents

wildbillbugman
03-30-2012, 05:26 PM
Thanks T-Grain,
This meens that I will put that project way way on the most rear burner. I think that someone will make a gelatin based pan emulsion in the not too distant future. But I do intend to try Jim's idea of adding pigments to a pan emulsion.
Bill

Photo Engineer
03-30-2012, 06:42 PM
T-Grain;

The authentic receiving layer in the Dye Transfer process was a Thorium salt in gelatin. The Thorium precipitated the acid dye and therefore created a concentration gradient across the Matrix film into the receiver sheet. This method cannot be used today, but others have found ways to simulate this using Aluminum salts. The ph effect is there, but is a minor actor in the face of a mordant which actually precipitates the dye and totally removes it from action.

PE

dyetransfer
03-31-2012, 01:42 PM
Hi Bill - the idea for a carbon tissue utilizing silver halide instead of dichromate UV depends on a hardening action to occur, either when developing in a pyro developer, or using a bleach as in the old Kodak Wash Off Relief process. You would want to verify if either of these two image hardening techniques will work with PVA. The next thing to do is to determine how much pigment you need to get a good DMAX on the print. You would want to make up four types of 'tissue' (I would coat on mylar myself) : Cyan, Magenta, Yellow and Black. The pigments themselves will absorb the exposing light, giving the light penetration limiting effect. Exposure is from the emulsion side, unlike DT. The $10,000 question is: if you put in enough pigment for a good DMAX, can you still expose the emulsion? If speed is too slow, you could always formulate a faster emulsion. I don't think grain will be much of an issue. My guess is that it will work, since the absorbtion of the pigments will be similar to the dyes in Cibachrome, which has a decent DMAX - a slow speed, but usable.

Regards - Jim

T-grain
03-31-2012, 01:51 PM
Ron and Jim, I thought a Thorium salt was needed just to enhance sharpness not to actually hold the dye in the receiving gelatin?
Jim, when you say using bleach as in the old wash-off relief process-is this an etch-bleach process?
thanks

Photo Engineer
03-31-2012, 03:35 PM
T-Grain;

Thorium is a true mordant in the sense that the Azo-Sulfonate dyes precipitate as a Thorium salt. Today, Guanidinium salts and other positively charged quaternary ammonium salts are used as mordants.

As I understand it, the Thorium bound so tightly to the dyes that it does enhance sharpness relative to other mordants simply by tying the dye up strongly and quickly, preventing any bleed. Thorium also altered the hue of the cyan dye a tad. Jim probably has more on that.

PE

T-grain
03-31-2012, 04:00 PM
Ron, have you used any guanidinum salts as mordants in your dye-destruction experiments? BTW, how is going?

Photo Engineer
03-31-2012, 04:32 PM
I had intended to have some new ones done this week, but the workshop occupied too much of my time. Preparation and etc....

I have no mordant but have used it in experiments at EK. The dyes I have used, can be "self mordanted" due to their high molecular weight. At the present time, I am just imbibing them into the coatings. It works as a quick test.

I lack a cyan dye though. None of the ones I can get are azo dyes. They are anthroquinones which are not suitable. I prefer using a metal mordant such as Aluminum or the like.

PE

wildbillbugman
04-01-2012, 11:02 AM
Thank you Jim,
As of now, I have done exactly nothing to determine whether or not this PVA based panchro emulsion can be used as vehicle for printing pigments. But I have made 2 observations which may be relevent to the question of whether or not the base polymer will harden in pyro developer or a bleach out process. First, in trying to find an alternative to alcohol precipitation, I have found that a 7% of the the silane modified PVA in water will fall out of solution upon raising the pH with 1% KOH. After wahing the precipitate, lowering the Ph with sulfuric acid will not redesolve the polymer, no mater how long or how high the temperature. I conclude that a rise in pH has crosslinked the polymer. I am stil stuck with alcohol precipitation for the purpose of wahing the emulsion.
Secondly, I have found that pyro developer yields a rather low D-max, compared to D19, the later being my usual developer for testing purposes.
I am not sure that this means anything at all concerning the topic at hand. Just an observation.
Cheers,
Bill

wildbillbugman
04-01-2012, 11:07 AM
Sorry,
I left out a phrase. I meant to say-After washing the polymer and lowering the pH with H2SOS, I was still unable to re-disolve the polymer, regardless of heat.

Photo Engineer
04-01-2012, 11:56 AM
Bill;

Try ultrafiltration for washing. You don't need acid or base, just a filter and a pump. The setup is shown in both my book and the DVD in disk #2.

PE