Dry plates with acryllic or polycarbonate base

[Kirk Keyes]

Denise - what problems did the Pictorico have? Not sticking I assume, but can you give a more indepth answer.

[dwross]

Denise - what problems did the Pictorico have? Not sticking I assume, but can you give a more indepth answer.

Double bubble, toil and trouble, Kirk. The subbing grabbed the emulsion well so that it wouldn't slide smoothly and the emulsion clumped and gooped (a technical emulsion term, and a dark secret until now). But your assumption is spot on. The clumps and goops aren't going anywhere unless they would lift away along with the subbing in the developer. Mine never got that far.

[Steve Smith]

It is possible to buy polycarbonate and polyester with coatings or surface treatment to accept screen printed layers. I suspect that some of these treatments may also assist in bonding emulsion. It would require a bit of testing though.

In the US, the main manufacturers are General Electric (for Lexan polycarbonate) and Dupont (for Mylar polyester). It is also possible to get a polyester/polycarbonate blend from Bayer.


Steve.

[Kirk Keyes]

The subbing grabbed the emulsion well so that it wouldn't slide smoothly and the emulsion clumped and gooped (a technical emulsion term, and a dark secret until now).

What about prewetting the OTP sheet, perhaps with wetting agent, and then coating?

[Kirk Keyes]

Sounds like an cationic/anionic thing going on...

I understand if you have cationic emulsified asphalt that it will do the same thing you describe when you put it down on an anionic emulsified roadway, and vice versa.

[dwross]

Sounds like an cationic/anionic thing going on...

I understand if you have cationic emulsified asphalt that it will do the same thing you describe when you put it down on an anionic emulsified roadway, and vice versa.

Sounds like double bubble, toil and trouble to me.

Steve: Thanks for the brand name suggestions. I've written them down and stuck the note on my bulletin board for future reference. If I had to guess, I'd think that surfaces prepared for screen printing would have similar characteristics to OHP, which is made for inkjet printers, but any subtle differences just might make all the difference. As you say, testing will be required.

Right now, I'm holding on to the hope that Photographers' Formulary will start selling their Melenex again. If they don't or on some eventual day when it runs out, it will be time to go on a serious quest for available alternatives, or of course, a good recipe.

d

[Photo Engineer]

The OTP and indeed all digital print materials have a large load of mordant in a vehicle that absorbs a lot of water quickly. It therefore clumps and goops.

I have coated successfully on such materials, but the mordant reacts with 'something' and forms a dark brown stain at the end of the processing regardless of fix and wash times. Not good at all.

PE

[Aurum]

Sounds like an cationic/anionic thing going on...

I understand if you have cationic emulsified asphalt that it will do the same thing you describe when you put it down on an anionic emulsified roadway, and vice versa.

I know the cationic/anionic thing well. :o
I've worked in a factory where we made a range of bodylotions with anionic chemistry, and one solitary one with cationic (It was based on hair conditioner chemistry).

Try to pump one into a filling machine to displace the other (Known as bulk on bulk) when changing products. Not good.....
Think greasy scrambled eggs, rolled in cooking oil and cottage cheese.
The line setter who thought he'd save a hour or so on washdown ended up having the joy of stipping and cleaning the machine by hand.
He was on his own for that

Want to try this at home.. Mix a small quantity of a lotion type hair conditioner with a cheap body lotion. Yum

[Kirk Keyes]

Pretty crazy, huh?!

[Photo Engineer]

Well, you do not mix anionic and cationic organics that have high molecular weight. Otherwise, you get the result as described.

Just ordinary chemistry.

PE