Agfa-Gevaert Copyrex RN40 developer - still usable?

spaqin · Oct 11, 2020

Hey there,

A while back I got few boxes of something labeled as a developer, from a guy who's not into photography. As soon as I heard 'free developer', I agreed. However, as it turned out... there's absolutely no info online on what it is, how to use this, or even if it's of any worth. The box contains one brown bottle with the exact same label as the box. Does anyone know what was its purpose?
I haven't opened the bottle to smell it or anything. I'm also bit worried about the inflammable symbol on there.

Thanks.

AgX · Oct 11, 2020

"Open only in subdued light"

spaqin · Oct 11, 2020

Worry not! It was not in daylight, and even if I spoiled it somehow, I still have four more boxes of that

AgX · Oct 11, 2020

It is a photosensitive varnish (resist) intended for silk-screen printing.
But I am puzzled by the term "Developer".

railwayman3 · Oct 11, 2020

AgX said:
It is a photosensitive varnish (resist) intended for silk-screen printing.
But I am puzzled by the term "Developer".

The only information via Google seems to confirm this:- .

"The "Copyrex" trademark was registered in 1959 by Agfa for "LIGHT-SENSITIVE COPYING SOLUTIONS CONTAINING LIGHT-SENSITIVE SUBSTANCES AND RESINOUS MATERIALS DISSOLVED IN ORGANIC SOLVENTS, WHICH ARE USED TO PREPARE LIGHT-SENSITIVE COATINGS IN THE PRODUCTION OF PRINTING FORMS, AS WELL AS DEVELOPERS AND DILUENTS FOR USE IN CONJUNCTION THEREWITH".

So it's probably of little use as a developer for conventional films ?

spaqin · Oct 11, 2020

Thank you guys, at least now I know I have to think about disposing it safely

I think that RN40 was an entire series of different chemicals, for the 'copyrex' process. I am not knowledgeable about the printing process, so pardon if my assumptions are wrong.
Thus, the bottle I was gifted was only the developer part of the process - the actual varnish would be in a different container.

I may try to see if it reacts with film (just a quick test with a cut-off leader), but I don't think it will be of any good use.

AgX · Oct 11, 2020

railwayman3 said:
The only information via Google seems to confirm this:- .

You should hone your Google expertise...

It definitely is such photosensitive varnish.

MattKing · Oct 11, 2020

I'm guessing that it is the sort of developer I used to use after taking the plate out of the print shop's UV plate exposing unit (the "plate burner").
I would rub it on and the image would appear. After washing, the plate went on to the offset press.
IIRC, the stuff I used to use was a light pink in colour, it was quite viscous, and it smelled like varnish.

AgX · Oct 11, 2020

To my source it is the sensitive varnish, called RN 40. But it could well be that RN 40 is the designation of the system and not the component and then Matt could be right.
However, then there still would be seemingly the contradiction of the developer being light sensitive too.

Anyway that bottle must be at least 40 years old, as Gevaert still appeared as brand. (After the merger the Mortsel plant got specialized in technical products and the Leverkusen plant in consumer products. The technical products for some years still bear the brand Gevaert, even when made in Germany.)

AgX · Oct 11, 2020

Well I found out that RN 40 stands for a whole system.

AgX · Oct 11, 2020

Look here from page 15 onwards. If you want to find out about your product and don't bother to go through the translating. Your stuff likely coincides in function with RN20 (Solvent/Thinner) in this text:
http://oz5g.asuscomm.com:81/content/oz/1978/oz1978-01.pdf

Lachlan Young · Oct 11, 2020

As AgX has found, it seems likely part of a photoresist system, probably for processes related to circuit boards and/ or photolithography. It is likely a 'developer' in the sense that it's a solvent that removes the unexposed (uncrosslinked) resist. Some of these solvents can be extremely nasty either to the user or the environment - hence the move to resists that are often forms of photopolymer or use diazidostilbene etc.

If it's for a Polyvinyl Cinnamate resist, it may well be chlorobenzene in that bottle.

AgX · Oct 11, 2020

The resist was not Polyvinylcinnamate, but Polyisoprene based. (With a compound missing as Polyisoprene as such is not lightsensitive.)

But I do not know any applicable organic solvent that is lightsensitive, and the box obviously only contained that bottle.

railwayman3 · Oct 11, 2020

AgX said:
You should hone your Google expertise...

That's me put in my place, when I was only trying to help.

Shan't bother next time.

AgX · Oct 11, 2020

Don't take a comment of mine that serious.

Lachlan Young · Oct 11, 2020

AgX said:
The resist was not Polyvinylcinnamate, but Polyisoprene based. (With a compound missing as Polyisoprene as such is not lightsensitive.)

But I do not know any applicable organic solvent that is lightsensitive, and the box obviously only contained that bottle.

I've found RN-40 described conflictingly as Polyisoprene & as Polyvinylcinnamate based. Either way, it's a resin plus a sensitiser which is developed using a solvent that removes the non cross-linked resin.

There's a laundry list of solvents in Agfa's patents - all the usual nasties - one Agfa patent describes a developer made up from Benzene, Toluene and Chloroform - the latter is well known to be light sensitive - I would not be opening that bottle, but rather getting it to hazmat disposal post-haste.

AgX · Oct 11, 2020

Thank you for the hint at Chloroform, I completely forgot that it is not light-stable. Whether this though is enough to raise such advise on the box, as it is in a brown bottle anyway...

If so, then that all makes sense.

Agfa-Gevaert Copyrex RN40 developer - still usable?

Moderator

Privacy & Transparency

Privacy & Transparency