🎞️Black and White Image Processing

Difference between grayscale and black and white (binary)

Grayscale is a tonal representation that includes intermediate grays between white and black, typically expressed in 256 steps (0–255) for brightness. Black and white (binary) uses only two colors—black and white—with no grays in between. Monochrome is a broader term referring to any single-color tonal representation.

• Grayscale：An image with color removed, represented only by brightness levels, preserving the shadows and texture of the original photo.
• Black and white (binary)：A representation using only two colors—black and white—with no intermediate grays, so photos appear as clusters of dots or lines.
• Monochrome：A broad term for images represented in single-color tones, including not only black and white but also sepia tones and other single-color gradations.

What is sepia tone?

Sepia is a reddish-brown color widely known as the color of old photographs. It originally arose from processing to improve the preservation of black and white photographs. Today it is reproduced using color conversion that calculates brightness (luminance) and then maps that tonal range to a reddish-brown gradient.

• How the color is created：First, the brightness is calculated the same way as in black and white. Then the tonal range is passed through a curve that strengthens red and suppresses blue, transforming it into a dark brown (red 95, green 64, blue 43).
• Effect strength：The ratio of blending the converted color with the original color. At 100%, you get pure sepia; at 0%, the original color remains; in between, the original color shows through faintly.