Pictures Are Numbers

On a screen, a photo looks smooth. Zoom far in and you see tiny squares of solid colour. Each square is one pixel.

Computers do not store curves and brush strokes the way painters do. They store a table of numbers: for every pixel, how bright is red, green and blue.

Open the pixel grid lab. Click cells and watch RGB values change. You are editing numbers, not magic paint.

RGB stands for red, green, blue. Mixing them makes other colours on a glowing screen. Zero means off for that channel. Two hundred fifty-five often means full brightness for eight-bit images.

Black is zero, zero, zero. White is full on all three. Yellow is strong red and green with little blue.

Filters in apps multiply or shift these numbers. A darken filter lowers all three channels. That is maths on the grid.

A camera sensor counts light hitting each tiny spot. Those counts become pixel values saved in a file like JPEG or PNG.

More pixels mean more detail but bigger files. Next you will see how screen size and pixel count create sharp or blocky looks.

Keep the lab open. Try drawing a letter A with pixels only. Letters on screens are shapes made of lit squares too.