The amount of "precipitation gelatin" (the gelatin used at the beginning when you are putting the silver together with the salt to make a silver halide) is considered an emulsion variable. Some gelatin (or other colloid) has to be present to prevent big clumps of silver halide from falling straight to the bottom of the beaker as a useless mess, but generally the less that is present initially, the larger and faster the grains of sensitive silver formed. In other words, you'll get a much different emulsion if you start with all the gelatin. It's one of those things that is very educational to play around with. You might 'discover' an emulsion you really love.