Boaz Yakin is an American screenwriter and film director based in New York City. He has directed the films "Fresh", "Remember the Titans" and "Max", among others.
When I start thinking about how a movie I am working on should look, I tend to have an overall feeling and texture in mind.... a combination of what the photography, costumes and environment might look like, the feeling that they might evoke in tandem. The general style of the lighting, the colors, the tone of the architecture or living conditions being depicted, etc.
I almost never have a "look book" or something like that -- in fact, in talking to production designers at the beginning of each project, they are the ones who tend to bring in a book or examples of what they are thinking based on reading the script and any discussion we might have had. I tend to talk about the piece and the tone and style that I feel might be best, possibly refer to some other movies that I am thinking about, or a genre or period of movie that I am hoping to evoke, then open myself up to exploring what the production designer brings in terms of examples and ideas.
I know there are some directors who seek a very specific look right off the bat -- often people who have worked in commercials come at things like that. But I tend to see the "look" of a movie as something that develops somewhat more organically through the collaboration between the principal department heads. The DP, costume designer and production designer. That doesn't mean there is no intention or goal at the outset... there is... but I feel most comfortable communicating that idea through a number of different ways and examples, then letting the creative collaborators I'm working with start to bring ideas and suggestions of their own to the table. At that point the "focussing" process starts, because of course even with very specific examples, different people will be inspired in different directions. The specific style and ideas of the production designer and the other keys then need to be refined and refined through discussion and trial and error, and hopefully in a short enough time we are all on the same page in terms of the general intention and mood and look. After that it's the process of working through details, and that lasts from the first day of pre-production until the very end of shooting.