@K888D didn't seem to have any issues with bending black acrylic with his prototype (other than cutouts being too close to bends but that's an issue regardless of color). I wonder what problems they ran into?
I've only tried black so far and it has worked quite nicely, I'm not sure the exact brand of Acrylic which the forming company used though, there may be differences between brands on how well they bend.
As Aibohphobia mentioned we had trouble with cutouts being too close to bends, but I imagine this will apply to any type of Acrylic.
On our prototype we used a process called hot wire bending, this process involves heating a thin wire, the sheet is lay flat over the wire (few mm distance) on a bed which heats a line across the acrylic sheet, after a few minutes (depending on thickness of sheet) a lever is pulled which bends the sheet in the exact location of the heated area.
From my understanding this method is limited to small radius bends of under 1mm.
From what I can see in the picture above it looks like the white piece is the Acrylic? The bends in that piece have a quite large radius, perhaps 20mm?
There is another process you can use to bend acrylic called drape forming, I believe in this process the entire acrylic sheet is heated and then draped over a metal jig/tool, the heated sheet bends to take the shape of the tool. This process will allow you to form more organic shapes and also larger radii.
Perhaps this process of heating the sheet affects the surface finish, black may show it up more than white. Maybe a polished surface goes dull, or a matte surface goes shiny or patchy.
