Contrast, brightness and colour balance
The final image can enhanced by using photo-editing software such as Adobe Photoshop. Many packages offer an 'instant fix', or 'auto' option to correct colour balance, contrast, brightness etc, but it is often better to do this manually by viewing a histogram. In Photoshop, first load the image then either press the keys 'Ctrl' and 'L' together, or go to 'Image' - 'Adjust' - 'Levels', and this will bring up the image's histogram.
In example A, the image is under-exposed and this is indicated by the flat line to the right of the 'mountain'. This can be corrected by sliding the button to the left until it reaches the 'mountain'. This adjusts the red, green and blue (RGB) channels together, but it can be better to adjust each channel individually (example B). Example C shows the finished histogram and should provide a well exposed image. Adjusting the contrast and brightness might lead to some details or features in the image becoming obscured.
Use the clone brush (or clone stamp tool in Adobe Photoshop) to remove dust, spots, unwanted sections of the image.