You can expose a film from the wrong side. This will wash your pictures red or brownish.
What you'll need:
Redscale means you expose your film from the wrong side. A roll of film consists of a strip of plastic, with one side covered in emulsion. Normally, light hits the emulsion first, but in redscaled film, the light passes trough the strip of platic first. The result is a picture with a reddish tint.
Now you can buy that film ready made (in the shop at lomography.com for example), but it's much cheaper and more fun to make it yourself.
That's surprisingly easy. You need two rolls of film. One of those you sacrifice (or, if you home-process, just use one you allready processed. Just make sure you leave a short bit of film on it). Pull out all the film and cut it off, leaving a a few centimeters of film.
Than take a new roll and cut of the narrow leader.
Tape the two rolls together, making sure one shining side sits next to a dull side.
Now go into your darkroom, changing bag or dark bedroom with the covers over your head. Now use a paperclip or something similar to spool the film into the old, sacrificed, roll. Cut off at the end (but leave a few centimeters for next time, so you don't have to keep sacrificing rolls). You can turn the lights back on now. Cut a new leader on your film. The leader should be on the top side.
And that's it! You can start taking pictures now. Redscale is pretty flexible, but it needs more light that regular film. I'd say, overexpose at least a full stop. So if you redscale a 200 iso film, you should expose it as if it's 100 iso. You can overexpose even more than that. In fact, overexposing more or less changes how your picture will look. Underexposing (less light) will give fiery reds, overexposing (more light) will produce orange, light brown, sepia... The more light, the more it will approach natural colors (but it'll nevel go all the way, you'll always get a kind of vintagy look).
