QPcard 101: White/Gray Balance, Exposure Control and Contrast Management Reference Card
QPcard 101 is an inexpensive pocket reference card (142×40 mm) used for white and gray balance, contrast management and exposure control. The card is manufactured on special paper that does not use UV-reactive whitening agents. The three patches have almost perfectly straight spectral response and are highly fade-resistant. The materials used in the QPcard are specifically selected to avoid metameric effect.
The front face of the QPcard 101 has three patches: white (Lab value 95*0*0), medium-gray (Lab value 48*0*0) and dark-grey (Lab value 35*0*0). The mid-gray reflects 18% of the falling light which makes it very well suited for determining the correct exposure. The white and dark grey patches are used for controlling picture contrast during shooting and image processing.
The back of the QPcard 101 has an adhesive layer similar to that of Post-It® notes. It allows easy attachment of the reference card on almost any kind of surface.