11:18 Nov 11, 2011 

conformal layers/coatings came up very recently in a previous, unrelated question. Generally speaking (though not always) conformal coatings are transparent to enable one to see the markings on the components. They also make it quite tricky to rework or repair the boards

10:31 Nov 11, 2011 

The green gunk I'm talking about is an overall coating that covers the traces (and everything else). I've just looked it up and what I'm talking about is "conformal coating" (http://en.wikipedia.org/wiki/Conformal_coating) as already mentioned below.

However, as Chris says, it doesn't seem to fit the context very well.

10:05 Nov 11, 2011 

The "green gunk" is silk-screen printed (selectively) and is called "solder mask" - to prevent the solder from adhering to copper parts (traces) that are not intended to get extra solder.

09:53 Nov 11, 2011 

that they spray all over finished circuit boards.

08:40 Nov 11, 2011 

it's unlikely to be a sail, veil or wall, so a painted finishing coat would seem the most likely. I get the impression the whole apparatus, not specifically a pcb, is being discussed, so a conformal coating would be improbable, especially being described as "mise en peinture".

08:08 Nov 11, 2011 

No more context is provided. Its a small excel file which just few points like this.

08:06 Nov 11, 2011 

If it is a printed circuit board - it might make sense.

08:02 Nov 11, 2011 

Please can you tell us what kind of apparatus or installation is involved here?