Basic exposure effects?

[mrburnzie]

Hello!

How do I achieve exposure with imagemagick?

Examples with the apple exposure effect:
https://postimg.org/image/52350k2xl/
https://postimg.org/image/5s5y2wiu7/

Thanks!

[fmw42]

We do not know what apple is doing. But you can get exposure changes in a number of ways. If on Unix (not windows), I have a script calle exposure and another called xposure at the link below. Otherwise, use -brightness-contrast or -level.

Please always provide your IM version and platform.

[snibgo]

I don't know what Apple is doing.

For a close approximation to changing the cameras exposure, assuming you use sRGB colorspace, add or subtract a certain amount. Depending on many factors, 10% of quantum is approximately equivalent to one stop on the camera.

Code: Select all

convert in.png -evaluate add 20% out.png

This brightens the image by approximately two stops.

(This may not be entirely accurate. You would need to test your camera, photographing a gray card at different exposures to see if 10% is correct, and to see whether the same amount can be used across the entire range.)