Konica plate coatings

[ron olson]

I recently purchased some Konica plates 32" x 24" and I need help in determining how to remove what must be an anti-hallation coating on the non-emulsion side. Unlike other coatings with which I am familiar, this one (its a bright fushia color) doesn't come off in a water/alcohol bath. It does however come off in my developer (SM-6) unfortuantely that's a bit late in the game. It resists scrubbing - the stuff is very hard and I'm hoping someone will know what I can safely use to remove it as it strongly attenuates the object beam in my H2 set-up. These plates are too nice to use for H1 transmissions although that remains an option. I tried ascorbic acid on its own with no luck but it does seem to come off in sodium hydroxide (12g /liter as per my SM-6). Any thoughts on the best course of action - I am looking to produce a dozen big H2 reflections and the substrate thickness (along with the coating) makes cutting up test plates a dodgy proposition.

[Jeffrey Weil]

Hello Ron,

It sounds like the same coating that was on the old Kodak HRP plates we used to use for 2d-3d's in the embossed world.

Anything base will remove it, but only base. Just like you I've not had any luck with acids, solvents, etc...

I also used sodium hydroxide to remove it, I've never tried sodium bicarb. That might be better.

I think your going to have problems if you try to do this in a tray and have the emulsion soak up the base chem. You might have to wash the back by hand being careful not to get any on the gelatin. What a pia!

Jeff weil

[Martin]

I recently purchased some Konica plates 32" x 24" and I need help in determining how to remove what must be an anti-hallation coating on the non-emulsion side. Unlike other coatings with which I am familiar, this one (its a bright fushia color) doesn't come off in a water/alcohol bath. It does however come off in my developer (SM-6) unfortuantely that's a bit late in the game. It resists scrubbing - the stuff is very hard and I'm hoping someone will know what I can safely use to remove it as it strongly attenuates the object beam in my H2 set-up.

Sounds like most alkali stuff will remove that anti-halation coating. I guess you might use a diluted ammonia solution (maybe 5% or so) from a pump spray. That won't leave any marks on drying. By the way, some window cleaners are based on ammonia.

Regarding the Konica plates, that's the material designed for the Voxel system?

[Tom B.]

Could try shaving with clean single edge razor blades - this seemed to remove mild paint overspray and other contaminants from my car windows
amazingly well. For your plate AH coating maybe best in combination with a mild alkali (baking soda?).

[BobH]

How about soaking paper towels in a strong alkaline solution and laying the plate on top of that, so the coating is in contact but the fluid is prevented from coming in contact with the emulsion? Might dissolve it enough to be wiped off, again with alkali soaked towels?

[Ed Wesly]

Another chemical to try on the AH backing that might be less damaging is sodium sulfite. This is one of the reasons that Kodak would put so much of it in D-19 and the like, to dissolve the AH backing.

How come when you want it no one makes it and when you don't want it, it's there?

[ron olson]

Thanks for all the suggestions guys. I got reasonable results using developer just before it was ready to be tossed, still not quite on par with what it was expecting.
I also tried a weak ammonium solution but not in the manner that Bob suggested. When I find the best technique, I'll post it.
If women weren't so beautiful, I'd say it wasn't worth the hassle but 32" x 24" plates accomodate such a lovely volume.

[holorefugee]

If women weren't so beautiful, I'd say it wasn't worth the hassle but 32" x 24" plates accomodate such a lovely volume.