takes some South Africans and turns them into urban bad guys.
This is a really good time to finish the minis with a coat of gloss varnish, to protect them for gaming, followed by a coat of matt varnish to flatten the paint again.
Catastrophe!
I had been terrain-building out in the garage at the same time, and went to spray the varnish after I'd finished mixing and pouring plaster. I thought I'd only been out in the cold a couple of minutes, but it was obviously long enough to chill the can and 'frost' the varnish.
Realistically, if you apply a filter, you don't need to give the minis a gloss varnish afterwards, because the filter is based on what is essentially gloss varnish - but Bill had mentioned he was planning to use these minis for demo games, so I had figured it was best to have a little more varnish than necessary on them, rather than a little too little. I was really regretting that decision at this point!
Hold on, hold on... don't panic
I know how to deal with this. The difference between gloss and matt varnish is the surface texture. Gloss varnish, at the top, dries (usually) with a totally smooth surface texture, so all the light is reflected in the same direction and it looks all shiny. Matt varnish, at the bottom, dries with a microscopically bumpy surface, so the light is scattered all over the place and you don't get any sharp bright highlights, and the surface looks dull.
When frosting occurs, often as a result of spraying when it's too humid or your can is too cold, the gloss varnish gets a bumpy surface like the matt one, only worse.
The obvious solution, then, is to spray with more gloss varnish, right?
...no, if anything that looks even worse than before. Darn it!
The way you can tell that the frosting is reversible is to wipe the mini with a wet cloth or cotton-wool bud; the water fills in the bumps and reflects light off its own smooth surface (the same reason wet asphalt looks shiny) - so if the mini looks OK when it's soaking wet, it should be possible to reverse the frosting effect.
I've found in the past that you can sometimes just scrub frosting away entirely with a wet cotton-wool bud, but these minis are rather too small and sharply-detailed for that.
More spray varnish didn't help... but a hand-applied coat of floor acrylic, in the end, rescued the miniatures. I've since heard rumours that the brand of gloss varnish I was using is particularly susceptible to frosting - I'd not had any problems with it previously, but I'll try a different brand next time, just in case.
Here the mini on the left shows the 'frosted' condition, the middle one has had the floor acrylic applied, and the one on the right has been finished off with a coat of matt varnish to dull the gloss back down.