Step 6: Latex
Goes on thicker than a paint, but stays put very well. If you have an allergy to latex, DO NOT USE IT.
Latex peels off rather than washing, and it can be a problem if using over large parts of your body - it's also expensive.
Pros: If you need the equivalent of a latex body suit - this is the way to go - but only if you want a shiny, fake look. Primarily, latex will work great for details such as fish scales, spots, as instant pasty and other places you would want to have a raised look, or if you want to stick glitter securely to the body. One big advantage to latex is, if you have the body for it, you can do painted superhero quite easily. You can achieve shapes with latex that you just can't do with paint alone. You can build up layers to make battle damage, wounds and zombies or to create face-melting effects. It makes great puffy scars, bald caps, and is otherwise incredibly versatile. You can create things like elf ears and scabs in molds and apply them to your body later.
When applying and while wet, throw glitter onto latex spots and it will stay there! You can paint dry latex with regular make up to create an even more interesting look.
Cons: Latex will stain clothing when wet. If using with clothing, put on after the latex is dry. Additionally, latex needs a finishing powder to make it set. Latex can peel off on it's own if you aren't careful. Once a peel has begun, it can be hard to control, and will be distracting. Latex is finicky - if you tear a latex ear, there's no repairing it. It can stretch in less than ideal ways. Additionally, it smells like the dickens.
Also, latex does not breathe nor absorb liquids. Try not to get too warm if wearing a lot of it, because sweat doesn't have anywhere to go but away from your skin.
Apply with a foam brush you don't plan to use again, with a separate brush for each color, and make sure you have a fan running or a window open with a cross breeze. Stand on newspapers or drop clothes, a plastic tarp or something else you don't care about. Do not apply without a 24-48 hour skin test first, even if you don't have a latex allergy. If possible, have a friend apply the latex to you rather than trying to do it all yourself - chances are, you'll need someone to do parts you can't reach easily anyway, without warping the latex you already have on.
Latex is not something I would use if I were planning on moving around a lot - standing and walking, fine, but I wouldn't drink anything for several hours before using or while wearing- if covering your hands, you won't be able to wash them and I don't know how anti-bacterial gel would react if at all. I would do my best not to sit while wearing latex - the less body deformation, the better. You might be tempted to do power poses if dressing as a super hero, but fully test all poses you plan to do before leaving your preparation area. Don't try the split leg crouch with arms outstretched for the first time on the convention floor.
Under the right circumstances, latex can be completely worth it.
(I swear to god, I didn't look for blue colored latex paint, it was just one of the first things that came up.)