Priming Minis

Priming miniatures is a necessary evil. If you don't, or think you'll be able to get away without bothering, you will find that the layers of paint you apply will rub off very easily. From experience I have found that spray priming is the most efficient and best way of doing things. Trying to hand paint on an undercoat is time consuming and less effective. The primer actually corrodes the surface of the miniature very slightly to give the paint grip so that it will adhere to the surface.
I tend to prime using black for the most part as it provides an automatic shading and stands out less if you leave a part unpainted, grey or white if I feel that the miniature would benefit from a lighter colour. An example is my Uncharted Seas Imperial Navy - the hulls were primed black to add to the depth of the colour, however the sails were primed in white so that they had a vibrancy to help set them apart from the dirtier sails of the orcs. The Zombies I am painting are all being primed with grey as it is such a neutral and bland colour that makes the dead flesh a lot easier to paint.
For the longest of times I used GW (Games Workshop) Spray paint religiously, recently - with a student budget - I have go into using car primers. There are 2 main reasons for choosing car primer; it is about half the price, and it also does a better job. With car primer, a light coat that hardly seems to cover the miniature (the metal/plastic still shows through to a small degree and the detail is not obscured at all) provides an excellent purchase for later layers. GW Spray needs a solid coat, usually 2 thin layers to get the same level of purchase whilst obscuring more of the detail. Having said all of this, you need to be careful that the car primer you get is a good matt finish, a few of the 'primers' I have tried have given a very gloss finish that is next to impossible to paint over and has made life a lot harder ALWAYS TEST IF YOU HAVEN'T TRIED IT BEFORE!
Some of the other companies that manufacture spray primers specifically for miniatures include Humbrol, Vallejio and Army Painter. I know Humbrol to be decent, much like the GW primers. I haven't tried the other two, but I have heard very good things about Army Painter Spray Paints, and if I were to ever paint a large number of miniatures in a color similar to one of their primers, I would give them a go. Vallejio Sprays I have heard very little about with only one report of their primers which described them as very watery. This brings me on to my final point:
What ever primer you end up going with - read the instructions, it will tell you to shake the can thoroughly for at least 30seconds (I would recommend 2-3 minutes). The importance of this step cannot be over stated! If you don't shake the mix well enough, you will end up with a watter finish that will only settle in the cracks. This will not only result in poor basecoating of the mini, but it will also result in obscured details as the paint settles in all the recesses rather than evenly across the surface.
Raggy, signing out