Photoshop by Numbers

Photoshop by the Numbers

"Photoshop by the Numbers" is a series of articles about everything related to numbers in digital photography and retouching.

Photoshop is full of numbers. Resize an image, or change its resolution, and you have to enter numbers. The Unsharp Mask filter asks you to provide three numbers; a Levels adjustment five. Bit depth can be 8, 16 or 32: numbers. Open the Info panel, move the mouse over your image and you see many numbers. A color cast can be corrected "by the numbers".

A digital image is nothing but a rectangle of colored pixels, where every pixel is represented by a set of numbers. Any manipulation of the image - lightening, sharpening, neutralizing, blending, etc. etc. - means that some arithmetic is applied to those numbers.

"Photoshop by the Numbers" studies "the numbers of a photograph": their meaning, relevance and relationships.

I investigate and explain RGB values, but also LAB, CMYK and HSB color spaces, color profiles, 8-bit vs. 16-bit vs. 32-bit, the effect of adjustments, masks and blend modes on pixel values, image size and resolution and much, much more.

List of articles

Possible numbers for skin color