V Flat. Ideally the form core is black on one side and white on the other size. Overview of very useful accessory called V-flat which is very convenient to work in the studio.

And for travel the 70 lb V-Flat folds to a compact 400 x 400 x 20. V-Flats are 2 4x8 Foamcore panels unassembled that are Gaff taped together to provide professional light reflection or background setting. Measure a piece of gaff tape that is slightly longer than your foam core board.
He demonstrates using the V-Flats for fill light subtracting light background to light.
VFlat is a scanning app that makes images taken with a mobile phone such as documents books and notes into high-quality PDF or JPG images. A v-flat is two pieces of plain colored background board connected at a 90 degree angle. You cant imagine how useful a dumb piece of black and white foam could be. Hinged design dual sided V-Flat VERSATILE.