Final answer:
The appropriate term for the sketch of Tim's photo session is either an 'observational drawing' if it aims at capturing real details or a 'concept sketch' if it is a preliminary representation of ideas. These terms reflect the process of translating observations or concepts to paper, significant in photography and other art forms.
Step-by-step explanation:
What term describes the sketch of Tim's photo session? The appropriate term for the sketch of Tim's photo session could be an observational drawing or a concept sketch, depending on the context. If the sketch is focused on capturing the details and atmosphere of the photo session as accurately as possible, observational drawing would be the fitting term. However, if the sketch serves as a preliminary visual representation of ideas for the photo session, concept sketch is more appropriate. Both terms involve the process of visually translating observations or ideas onto paper, and they are crucial in various art and design disciplines, including photography. We know from the information provided that photography as an art form can involve different approaches, such as Stieglitz's transformation of photography into more painterly scenes with techniques that enable spontaneous capture of moments instead of posed images. Similarly, David Hockney's use of composition and perspective to create an emotional scene or Timothy O'Sullivan's depiction of the grim realities of war through stark imagery serves as bold examples where initial sketches might play a role in the creative process.