Complex sentence: Photographic emulsion is not a true emulsion, but a suspension of solid particles (silver halide) in a fluid (gelatin in solution); however, the word "emulsion" is customarily used in a photographic context.
Split into simpler sentences: Photographic emulsion is not a true emulsion, but a suspension of solid particles (silver halide) in a fluid (gelatin in solution). However, the word "emulsion" is customarily used in a photographic context.