Seamless Blending of Prosthetic Effects - Part 1
There are two types of edge for blending. One is thin and subtle, the other is thicker and more obvious. Thin and smooth edges allow for full variation in makeup styles, whereas the thicker sort normally call for a heavier make up application. The problem is that getting the thin edges is often near impossible, particularly with budget special effects.
Many of the tutorials here suggest ways to improve your prosthetic edges, but in my experience sometimes it just doesn't happen. Be it temperature, the mix of gelatine, the material of the mould or just bad luck you end up with a thick edge that might even need cutting. Rather than scrapping things, I am of the school that thinks "hey, lets do what we can with this". None of the examples on this site are perfect, I attempt where I can to show you why.
Another aspect that you often will have more control over is the color of the prosthetic. Liquid latex and paper construction will usually be a yellowish white, which will need work. As described in the foamed gelatine tutorial, using acrylics to colour your gelatine base will provide a solid start, but sometimes you may not know the skin tone of your zombie in advance, or may not have the right color prosthetic for other reasons. If in doubt, leave it the opaque yellowish colour that gelatine is naturally when foamed. This will take any makeup applied after easily, and blending can be done at that stage.
If using latex, or particularly Elmers Glue, you will have a problem with the texture border between it and skin. Skin is not smooth, it has a texture not unlike an orange peel, with dimples and pores. Clean skin, washed with soap, also is not greasy, and will take makeup easily. Latex, on the other hand, is a type of rubber, and PVA glue is a type of plastic. These substances often have a shiny impermeable surface that make them watertight (think of some of the useful applications of latex), but this also makes them extremely difficult to apply makeup to. Often the edges of these will require heavier covering, with greasepaints and other dark colors.
Plain gelatine skin sheets will sometimes have similar problems to latex, but they are generally more porous. Foamed gelatine though is about as good as it gets. One of the trial-and-error arts of foamed gelatine is getting the bubble size right. With multiple tests and some dumb luck, you can achieve a texture extremely similar to porous skin, which takes makeup almost identically. This, combined with well-thinned edges will allow for near-seamless prosthetics that will hold up even under flash bulbs and other harsh light conditions. Even a badly done gelatine prosthetic will usually be easier to blend than latex, certainly for the 'realistic zombie' look.
Cheap Costume Makeup
Standard greasepaint makeup from costume stores and 'halloween style' creampaints are thick and stylised. Their heavy application makes them effective at covering nearly anything. If you are looking for the pale white / green zombie look these will do the job admirably. Even on top of latex they will cover edges and seams, and the whole-face look of pure white can be extremely eerie.
As with all bases, cream makeup should be applied in a 'dabbing' manner, preferably with the finger or a fine sponge. Once an even covering is achieved, use a powder to set the makeup and take the sheen off it. For these simple white and green bases using talcum/baby powder will work. A wide soft brush is best for this, but a cotton pad will also work.
If you are looking to keep the 'just dead' look to your zombie you will need to invest in some conventional retail cosmetics. I will restate here, it's not a good idea to 'borrow' these off female relatives as they are often a lot more expensive than they appear. Still, you do not have to buy expensive makeup. Cheaper powders and foundations aimed at the younger markets are in the 1-5 dollar bracket, and are a fantastic addition to the serious zombie toolkit.
The bare essentials for this are a cream foundation of a color as close to your target zombie as possible, and a powder, also in the correct colour range (although obviously greener shades work well). Foundation can be applied with the finger, but the powder will require a brush. Cheap brushes will shed hairs, but for a short season of zombie make up you will be better off with a $1 brush than a $20 one. It should ideally be as soft as possible with a wide flat surface.
The next ultimate additions in the kit are dark eyeshadow, eyeliner pencil, and powders of green and yellow tones for bruising and trickier edge blending.