HELP!! - Coating Mask onto Autochrome Plates; it's not easy

Arrggghhhh!!

I've been trying for two weeks to get a good coating on the Autochrome plates, and it continues to confound me. The first thing that I learned is that with my current setup, I can't use and water-containing chemicals in the coating, as they make the water-soluable dyes that I used bleed. This eliminated a gelatine coating.

I also tried suspending the starch in some type of other liquid, and speading it across the plate using the liquid's surface tension. However, I cannot use organix solvents such as alcohols or acetone, as they destroy the dyes as well. I am thinking of using some type of an adhesive with the starch suspended, but this has proven to be quite difficult; I have epoxy, rubber cement, various glues and some silicone products. All of these either act as dye solvents, dry too quickly or are way too thick to coat evenly.

Does anybody have any suggestions as to how to coat the plates? Perhaps I'm taking the wrong approach? Help Please!!

To start of with testing, I have made a 1200 dpi mask on a color laser printer, which I'm going to do initial testing with.

Have you tried a thin layer of adhesive on the plate then shaking a layer of mixed colors starch grains on it? Afterwards shaking off the excess and pressing the starch into the surface?

Good idea, but my main problem is that hte starch clumps together when in the container; shaking on an even layer is hard.

It's also problematic to coat the adhesive on the plate evenly; i need something thin; perhaps spray adhesive?

Dilute some rubber cement with a quick drying solvent. After the solvent goes away the rubber cement is still tacky. You should be able to make a pretty thin coating with that.As far as the clumping, sounds like the starch is still moist.

Good idea. I'll pull out some organic solvents and start testing. Any specific reccomentations? Otherwise, I'll try acetone, benzene, xylene and Ethanol.

Quite some time back this was mentioned in a post.

Have you tried making an insoluable salt of the dyes? Calcium salts are the one I would recommend as a starter with Barium salts as backup.

That will make them quite insoluable and is how I did it when I was doing something similar.

As for coating or using solvents, remember that an organic hydrophobic phase can cause problems of another sort.

Have you tried contacting the resource that I sent you? He has lots of information on this type of problem.

PE

Oh, wow, PE, that slipped my mind, argh. Could I simply place the dyed starch in a calcium chloride or other calcium sal to precipitate the dye in situ on the starch?

I have not contacted him yet; I'll do so, though. Thanks. Do you happen to have an e-mail address for said Autochrome expert?

Perhaps I'm being a little dense here ...

htmlguru4242 said:

Oh, wow, PE, that slipped my mind, argh. Could I simply place the dyed starch in a calcium chloride or other calcium sal to precipitate the dye in situ on the starch?

I have not contacted him yet; I'll do so, though. Thanks. Do you happen to have an e-mail address for said Autochrome expert?

Perhaps I'm being a little dense here ...

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I think that washing the dye in starch with a solution of calcium chloride would do the job at least as a starting point. You must remove the excess salts though or they will cause problems down the line.

When I did it, I placed the dye into solution and added it to gelatin. Then I added a solution of CaCl2 to the gelatin and the ppt formed suspended in the gelatin. Then I chill set the gelatin and noodled and washed it to remove the excess calcium and chloride ions. Then I mixed that with my emulsion and coated it. This was the basis for my ciiba/ilfochrome coating experiments.

The person who I referred you to is in contact with several Autochrome experts. He can supply you with their e-mail addresses. I have no direct contact with any of them in France except through third parties.

I have talked to a number of these third parties, and they tell me that there has been considerable effort, in France, to reproduce Autochromes even using the original equipment which was recently reconditioned. I have not talked to the actual experimenters.

I refer you to them for details through the e-mail I gave you.

If you wish more information or references, please e-mail me. I'll do the best I can. But, one of the expert third parties that I correspond with has posted on your original thread.

PE

Wow PE you're a gold mine! I hope this gets you something good going htmlguru. I'd love to see this pulled off.

glbeas said:

Wow PE you're a gold mine! I hope this gets you something good going htmlguru. I'd love to see this pulled off.

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Thanks Gary, I wish him well also.

I just try to share what I know.

PE

htmlguru4242 said:

Good idea, but my main problem is that hte starch clumps together when in the container; shaking on an even layer is hard.

Click to expand...

You need a "sugar caster" -- it's used in baking, to apply a thin, even layer of powdered sugar to a confection or small cake. It's similar to a small flour sifter, using a moving friction wire to feed controlled amounts of powder through a fine screen. In fact, just a screen, as in a strainer, might work for you; load the strainer and just shake it horizontally to distribute the starch grains. Otherwise, its off to the kitchen store (but start at Goodwill; stuff like this turns up from time to time, and folks don't buy it because they don't know what it is).