Lighting correction

What is colour cast

RAW
When working with a RAW file, changing the brightness and colour cast is easy as pie, simple set your White Balance to the specific lighting conditions the photograph was taken with (of switch through to see which one looks best). What you are aiming for is some thing that is white to be as white as possible.

As  you can see in the photo to the left, the whole image has a Yellow cast over it making the grass appear yellow and the horse is too light, so the image needs to be darkened.

To get rid of the cast, change the White Balance.

To make the photograph darker or lighter, the best way is to use the 'Exposure', it works well and does not degrade the image for up to 2 stops of a cameras F-stops.






The finished image makes the horse look white and the grass look green, that is how I know the colour balance and exposure are correctly set.



Not RAW
Correctly editing the colour balance with a jpeg or none RAW file is significantly harder/more time consuming which is why I would recommend shooting in RAW format whenever possible.

First I applied the Brightness/contrast layer, which enabled me to make the photo darker as it was too bright at the start.
In this example I set the brightness to -73 however you will want to adjust for the correct effect.




Next I applied the 'Color Balance' layer, depending on the color you want, you can use the sliders to control each specific colour, doing this is more of an art than a science, you have to gauge by eye what colour is correct, again you want the whites to appear white and the rest should fit in place.
A rule of thumb is you want the numbers to add up to 100, although some times 'correct' looks 'wrong'.



levels

The graph shows where the information in the photograph is, the higher the graph, the higher the amount of information being stored on that specific level of black and white.

By moving the arrows underneath, the brightness can be changed and lets you make sure you are not degrading your image. The black arrow sliding to the right makes the image darker, and moving the white one adjusts the white, moving it left will brighten the image.
The grey arrow sets where on the line between black and white grey is.

Moving the BnW arrows into an area with a lot of information will cause image degradation which may be a problem if you want to maintain the photo at a large dimension.





Levels can be used to brighten an image and some times make a none white background completely white.