Spotting; watching a movie and deciding where to put the music and how the music will sound. That is the most blunt way to describe the process of “spotting” a movie that I can think of.
On a deeper level, spotting is using your emotional palette as a composer to enhance a scene. Meticulously reviewing a film for the exact moments in which your magical sound-butter will grace the screen. Composer be-ware, however; callously littering a film with cues may potentially RUIN the entire project. Despite your $2 million dollar budget, first-rate orchestrations, fantastic themes, 12 week deadline (a luxury); if you’ve cued a whimsical pirate theme to what was INTENDED by the director to be a somber funeral scene, you sir (madam), have FAILED. Can’t emphasize this enough. The music needs to fit.
If you’ve just begun your journey as a film composer, fresh off the boat, you might fail to grasp immediately that spotting is indeed a complex art form. Amateur film composers tend to “over-do” things a little. Too much music here when there shouldn’t be any, not enough, overpowering music when there’s dialogue… etc. and the list goes on. Fear not though, this all comes with experience. An experienced composer will have developed his/her sense of musical appropriateness, donning the impressionists hat and taking their own impressions from the screen and applying them.