This gives an other-worldly effect to your pictures providing you use the appropriate filtration. For instance, Kodak T-Max films exhibit reduced blue sensitivity and increased orange sensitivity as compared with Ilford Delta films. In color, there are films for specific lighting conditions, too. Daylight-balanced film is perfect for outdoor or flash lighting, but will give very odd yellow color rendition under tungsten light unless a filter is used. Tungsten film is designed for use with tungsten light, but will give very odd blue color rendition if used with daylight or flash light.
Chromogenic films are black and white films based on color negative technology.
They can be developed in any C-41 compatible process, by any minilab. The final image is not formed from silver grains, but from clumps of dye. But find a good, reliable lab and the convenience and quality can be marvelous. Crystal habit is one of the more arcane terms that you may hear applied to film. This refers to the way in which crystals form.