In Claus's recent posts about his many new 3D designed puzzles, I asked him not to take pictures using a patterned background (wood, fabric etc.) because this makes picture editing much more difficult. I suggested that white puzzles should be taken against a dark background and black puzzles against a white background.
However, I although black (or coloured I suppose) against white is OK, I have found that white against a totally black background is not so successful. The main problem is that, if you are using a single light source to illuminate the puzzle (e.g. a camera flash) then, because of the black background, there is no "back scatter" illumination of the puzzle, making some faces very dark, and the edges of these faces tend to "disappear" into the background, making picture editing just guesswork. Also, relying on the camera's automatic exposure settings can be a bit hit and miss with so much black in the picture.
So, if you are photographing a white puzzle, I think that the background should be a mid-light-grey colour, which will provide enough edge contrast to make editing easier, while providing some back scatter illumination.
Of course multiple light sources would help, or even better a light box
, or even better you edit your own images
, but I understand that most members just use a single camera or phone to take pictures, so correct choice of the background is critical.