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Adjusting colour balance & sharpness
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Adjusting colour balance
In Photoshop, the colour balance adjustment (accessible via 'Image>adjust>color
balance') looks like this:
It allows you to adjust the colour balance of shadows, midtones and highlights
in the three separate colour channels (red, green and blue).
Selecting 'Image>adjust>variations' shows you a range of previews
of colour and brightness adjustments for your image if you are
unsure about using the tools, this can be quite useful.
It may also be useful to create 'adjustment layers' ('Layer>new adjustment
layer'), where you can experiment with setting levels, colour balance,
and other adjustments without affecting the original image. The image
becomes flattened when it is saved for web, and can be saved as a Photoshop
file if you want to keep the layered file.
Adjusting sharpness
The unsharp mask filter (in Photoshop via 'Filters>sharpen>unsharp
mask') is the most useful tool for sharpening your image. It works by
slightly increasing the contrast in pixels along the edges of objects,
and can be very effective.
Almost all scanned images can benefit from a small degree of sharpening.
It may be possible to sharpen the image during the scan, but it should
preferably be the final adjustment that you make to the image, so is better
done at the image editing stage. Photoshop's filter uses a scale from
1-500%: 50-100%, with a pixel radius of 1-2, and a threshold of 0-10 is
usually quite enough. Sometimes, if your image is grainy or has high contrast,
it will be better left unsharpened.
Fireworks has a filter with similar controls in the effects panel.
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