Imagemagick convert options

To maximize contrast:

-constrast-stretch 0 or -contrast-stretch 0x100% (or -contrast-stretch 0,100%)

This will find the min and max values and stretch them to full black and full white.

Note that 0x0 will take the min and stretch to black and the min again and stretch to white, so you will get all white

To clip a few percent from the white end, use 100-few percent.

-normalize is the same as -contrast-stretch 2x99% as it clips 2% from the low and 1% from the high