A method and an related apparatus for performing a white balance operation on an image with pixels, wherein global colour gain values common for substantially all pixels of the image are first determined. Then local colour gain values for individual pixels of the image are determined based on analyses of a local window comprising said individual pixel and a number of adjacent pixels. Thereafter, final colour gain values for individual pixels of the image are determined as a weighted average of the global and the local colour gain values, and a white balance operation is performed on the image using the final colour gain values.