: Improving the quality of a picture taken at night I took this photo at night: there is a green bush between the two chairs at the right, and green synthetic grass below the chairs, but

@Welton168

With ImageMagick,

magick chairs.jpg -resize 25% -gamma 4,6,4 chairs_464.jpg


Produced this



which is not as green as you'd probably like (there's really not much of a green component to amplify), but at least you can make out the scene a little better.

The command applies gamma separately to each channel (gamma_red=4, gamma_green=6, gamma_blue=4) to brighten them; here I was attempting to brighten the green channel more than the others.

ImageMagick has an "-auto-gamma" option that seems to be just as effective in handling underexposed photos. Here's the result of

magick chairs.jpg -resize 25% -auto-gamma chairs_autogamma.jpg




which uses the mean values of each color channel to come up with
the equivalent of

-gamma 4.616,4.649,4.680


Note that in earlier versions of ImageMagick, the command is "convert" instead of "magick".

With GIMP you can do more-or-less the same thing via the "colors/curves" menu item and lifting the middle of the curve to approximate a gamma curve.

EDIT: I've just become aware of Fred Weinhaus' "autotone" script, available from his website, for noncommercial use only. It does a pretty nice job on this image, when run with the default options:

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@Alves566

Green from things like grass doesn't really exist at night. There is not enough white light to reflect off the grass to create a green perception. You can confirm this with an eye drop of your image, even on the brightest part of the grass its leaning towards Magenta instead of Green.

So, can you fix this? It would require extensive masking and painting in exactly what you want and where otherwise you'll just have a big green color cast. The best way to fix this would be to take the photograph during the daytime.

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