This article is from the Miniatures Painting FAQ, by Brenda Klein email@example.com with numerous contributions by others.
An overcoat is a coat of clear paint that protects those colours you
so carefully put onto your miniature. Even an unhandled figure will
begin to dull after awhile, and one in regular use will lose its paint
even faster from hand and carrying case friction. So you should put
a protective coat over the miniature to make sure the paint remains
Overcoats come in three (possibly four) types: gloss, matte, flat, and
lusterless. Though four types are named, one company's matte is
another's flat, flat and lusterless are often interchanged, and matte
occasionally is labeled semi-gloss. When in doubt, test or ask.
Overcoats also come in two different applications, brush-on and spray.
Spray is easier to use when you want a uniform coating, brush-on is
good for when you only want certain parts covered. Spraying overcoat
on a miniature is much like spraying primer, though 3-5 coats is
recommended for maximum protection. Remember to begin and end the
spray beyond the miniature in order to get the cleanest application.
Gloss is just that, shiny. It is most usually used on cars and other
items that should shine.
Semi-gloss (satin, sometimes called matte) is low-luster, and very
durable on a figure that will be getting a lot of handling.
Unfortunately, it tends to look artificial on humans and some animals.
It's excellent on scales, however, and hard leather.
Flat (also sometimes matte) is nearly without shine. It's a good
all-around people coating, exceptional on animals, where it simulates
fur's natural shine.
Lusterless is absolutely flat, it doesn't even look like it's there.
It's perfect for people and cloth and anything else that should have
no shine whatsoever. Several coats can be applied and it never shows.
A good method of overcoating a realistic-looking human/humanoid is to
use a spray lusterless overcoat and put on 3-5 coats, then after the
last coat is dry, use a brush-on matte or gloss to go back over all
metallics, jewelry, eyes, lips, and anything else that should have a
shine to it. This is the author's favourite method.
Companies making overcoats are (+ denotes brush-on, = is spray): Armory (water-based acrylic): Glass - a high-gloss + Matte Sealer - low gloss = Floquil (oil-based enamels): Flat Finish - completely lusterless + High Gloss - very shiny, looks wet + Crystal-Cote - not quite as shiny + Al-Pro-Cote - flat finish + Glaze - a lovely matte/satin finish + Figure Flat - a low-shine matte = Floquil Flo-Stain (oil-based, for wood or over paint): Glaze - as above (I use this) + Crystal-Cote - also as above + Al-Pro-Cote - flat finish, no shine + Humbrol (oil based): Dull Cote - flat finish + Krylon (spray only) Clear Matte - low gloss = Model Master (oil-based): Lusterless - another lusterless = Gloss Finish - high-shine = Pactra (water-based enamels): Flat Clear - lusterless + Gloss Clear - shiny + Polly S (water-based acrylic): Gloss Finish - high shine + Flat Finish - lusterless + Ral Partha (acrylic) Spray Clear Matte Sealer - low gloss = Clear Sealer - matte finish + Testers (Oil-based enamels): Flat Finish - again, lusterless + Gloss Finish - shiny = DullCote - absolutely flat =