Facial Expressions for Commercial Looks
To understand ideal types of facial expressions for commercial looks more easily, it is important to contrast it against a theatrical look. Again, the theatrical look is about seriousness. If you are talking about roles, think about a cop that just uncovered new evidence, a villain about to commit a crime, and so on. So, there are no big smiles about it with theatrical shots.
With a commercial look it is about being the best friend, the friendly girl or guy next door, that person everyone wants to hang around. So, in contrast, we are talking inviting and warm smiles or facial expressions.
Of course, there are no rules written somewhere in the acting world that specifically defines each of these looks. You should still be yourself or the characters you can or want to pull off. So, there can be variances. There can even be shots that might blur the lines between both. The point here is to draw out the differences because in most cases, aspiring actors want succinct differences in these shots when they have them done.
Typical Uses for Commercial and Theatrical Headshots
To try and summarize one more way, commercial headshots can be used for movies, shows, theatre, advertising commercials, and more when you want to be cast as the helpful person, the boyfriend or girlfriend, the happy background actor, or the electronics store employee, respectively.
For theatrical looks, you might want these to be used to cast in movies, shows, theatre, advertising commercials and more as the hateful person, the suspect in a case, the villainous extra, or the mad customer at an electronics store, respectively.
Again, these looks span well beyond such roles. There are just attempts to continue to clarify what is meant in general when we refer to actor commercial versus theatrical looks.