Brightness

Multiply every color channel of the frame.

The multiply lands on the encoded signal rather than on linear light, which is what filter: brightness() in a browser does and what every backend here reaches for first. Black stays black and the result is clamped to the encoding's range, so a factor above 1f brightens until a channel saturates.

On an export that keeps an HDR grade the same factor is read as the display light ratio an SDR display would have produced, so a frame looks the same graded or not. HDR has headroom above white where SDR clips, so a factor above 1f matches an SDR export through the midtones and keeps going where that one saturates.

A run of color effects multiplies out before anything clamps, so a factor above 1f followed by its reciprocal returns the frame unchanged rather than a saturated frame the second factor darkens.

Throws