how to use curves in PS?

[erictan8888]

hi,

have been blindly following what some web sites teach about using curve....
using shift the circled portion up or down a little bit depending on my pic...

just like to find out more about using curves...
1. what exactly does shifting diffeerent parts of the curve do?
2. shifting the part circled in the pic above: it affects the brightness of which part of the pic?
3. how about shifting the curve by placing the mouse over at the mid-point of the straight line? which part of the pic does it affect?
4. how to effectively use curve in PS ?

thanks in advance.

 

[Amekaze]

This would be a good read for you.
http://www.thegoldenmean.com/technique/curves1.html

 

[erictan8888]

thanks a lot.... really clarified a lot of stuff...

thanks once again....

 

[Amekaze]

sure... practice makes perfect.
Curves are a hard thing to master.

 

[user111]

sometimes u use curves to reduce contrast instead of increasing it.

 

[KNIGHT ONG]

Interesting curves .. I am trying to adjust the light tones and dark tones in my B&W images but still need more time to practice ...

 

[2100]

Just a tip, do not go for more than 2 points. 3 is really the max....

 

[yanyewkay]

Just a tip, do not go for more than 2 points. 3 is really the max....

why's that so?

 

[2100]

why's that so?

Best way is to try in PS. It becomes really hard to control so as to get a "smooth" curve. A bumpy "aggressive" curve usually does not look nice unless in special cases (like you wanna do some special effects in sepia). What you are aiming for is a simple and smooth curve.

 

[rogersk8ter]

Some use curves...some use levels.....difference??