Occasionally when I talk about silhouettes, I don’t mean silhouettes-as-finished-art but silhouettes-as-part-of-the-process. See, for example Art Checklist (and writing) and the activities in Party Portrait.
Liking silhouettes as I do, I enjoy hiding line and colour layers occasionally, just to see what’s underneath them. But it’s also a useful way to assess the clarity of a design. Most of these unicorns (from this month’s calendar) are fairly self-explanatory, for example. But the one scratching itself needs a little more effort/horse experience to parse: not itself a bad thing, sometimes a silhouette can function as a gestural sketch, and compact designs are appealing.
Just seeing them in silhouette can also help show up anatomical or perspective vagaries — not always a problem, depending on style, but it’s nice if they’re deliberate (or at least plausibly deniable).
They’re also useful for assessing whether a certain mood is conveyed (this is from March’s Giants).
They’re also useful for assessing whether I’m happy with how the space is filled — whether it needs more variation, or pollen-dots to fill in vacuums (this one is from October’s “Cold Hands“).
I’ve been marking essays and commenting on scene cards, for uni, so I suppose the writing application for all this is — as for illustration — really an editing one. The effect can be replicated by writing an outline after the draft is finished, in order to see the clean shape or if any rowdy elements need to be pulled into line.