[galaxal]

I know level and curve are very power functions in photoshop, but i can't figure out how exactly they work, can you explain a little on that plz?

[Kebab]

You can set the highlights in an image by moving the levels input sliders to the first group of pixels on both ends of the histogram.
Doing so maps these pixels - the darkest and the lightest pixel in each channel - to black and white, increasing the tonal range of the image. The corresponding pixels in the other channels are adjusted proportionately to avoid altering the colour balance.

Like Levels, curves lets you adjust the tonal range of an image. However, instead of making the adjustments using three variables (highlights, midtones and shadows), you can adjust any point along the 255 scale while keeping up to 15 other values constant

I hope this will help you, it�s directly taken from the Photoshop 5.0 manual.

Regards. Kebab http://hem.passagen.se/kebab