Image Coloring

Halftone

Halftone is the reprographic technique that simulates continuous tone imagery through the use of dots, varying either in size, in shape or in spacing.

Examples of Color Halftoning with CMYK Separations

The first printed photo using a halftone(December 2, 1873)

Dithering

Dithering is a technique used in computer graphics to create the illusion of color depth in images with a limited color palette (color quantization)

Illusion of Dithering

256 color dithering with Irfan View

Original Image in Detail

Original image using the web-safe color palette with no dithering applied

Original image using the web-safe color palette with Floyd–Steinberg dithering

Original image has been reduced to a 256-color optimized palette with Floyd–Steinberg dithering

Depth is reduced to a 16-color optimized palette in this image, with no dithering

This image uses 16-color optimized palette with dithering

Original

Threshold

Random

Halftone

Ordered (Bayer)

Ordered (Void-and-cluster)

HSV Color Cylinder

YCrCb Sampling Format

YCrCb J:a:b

J: horizontal sampling reference (width of the conceptual region). Usually and in this case: 4.

a: number of chrominance samples (Cr, Cb) in the first row of J pixels

b: number of (additional) chrominance samples (Cr, Cb) in the second row of J pixels

YCrCb (4:4:4, 4:2:2, 4:2:0, 4:1:1)

YCrCb Sampling Format

4:2:0

4:4:4 4:2:2

4:1:1