The QP 4-Step Gray Scale Card is a unique item in the world of color management. This thick cardboard unit is divided in to four fields - equivalent to what Adobe Photoshop offers in their color management curve (4 points). These four colors provide a better evaluation of the gray scale.
The colors offered approach, but do not reach, the ends of the gray scale (absolute black and absolute white). All fields are neutral and work under a variety of lighting conditions. There are no fluorescence whitening agents involved, making the card perfect for Custom White Balance Setting in any light.
Measured L*a*b values are: 35*0*0, 48*0*0, 80*0*0 and 95*0*0
The spectral response is almost flat, making the card perfect in all light conditions, without causing any metameric problems
Metamerism - when two objects match in color under some lighting conditions, but not others
Larger measuring areas than traditional color-balancing cards