ISO 12640-3 standard image composition

The ISO 12640-3 standard image set consists of 8 natural images (photos) and 10 synthetic images made by computer.

Natural image

The natural image has a resolution of 12 pixels/mm, and uses 16-bit/channel L*, a*, b* values, and D50 illuminators.

2. Synthetic image

The synthetic image contains 8 chromatograms and 2 gradients.

(1) Chromatography

There are eight chromatograms in ISO 12640-3, each containing a number of color blocks used to construct the reference gamut, as shown in Figure 2. Each color gamut contains color patches that fall within 2 hue angles and are 180° apart. Since the image is 8-bit, the hue angle can be limited to about ±1°.

The chromatogram gives the L* interval of 10 (from L*=0 to L*=100) and the Cab* interval of 10 in the reference color gamut (maximum Cab* from Cab*=0 to the L* value of the current reference color gamut) ) sample. The size of each chromatogram is 275 mm x 137 mm, the size of each color block is 10 mm x 10 mm, the close distance is 1 mm, and the L* value of the gray background is 80.

(2) Gradient map

There are 2 gradient maps, as shown in Figure 3, a is the full color gamut, and b is the simplified color gamut. All gradients have 8 hue angles, from 0° to 315°, with an interval of 45°. The difference between the simplified gamut gradation and the full gamut gradation is that the minimum and maximum brightness of the full gamut gradation are L*=0 and L*=100, respectively, while the minimum and maximum brightness of the simplified gamut gradation is L*=10 and L*=90, the chroma is 85% of the full color gamut gradient.

The size of the gradation map is 250 mm long, 10 mm wide, and 4096 grades; the background is ash of L* = 80; the size of each group is 308 mm x 263 mm.