Silhouette in viewport while sculpting Is there a way to display an object in the viewport in one solid color against the background? In ZBrush it is frequently used to help judge the outside shapes of the model without internal details distracting you. 

I mean interactive viewport mode, while you can still sculpt, not make a one-off rendering. An example in use is here:

https://youtu.be/riyDQBJxSBQ?t=55
Assign the object an emissive material the color you want. Set the world background color to something you like, if you like.

Switch the view mode of your window to'Material'. If you want the new background color too, you'll have switch to 'Rendered'. I find a pie menu (with gestures) helps speed up the switch.

If you want a new background color without rendering, you can change that in User Preferences 'Themes'. If you need a quick switch of background color too, that's scriptable... see this BSE answer.