quantify with imageJ - unequal size of bands (Jan/16/2007 )

Hi,
I have a problem when trying to quantify bands from western blots.

As I understand all the boxes have to be the same size, but my bands are not. So if I draw a box that covers the largest band, some of the boxes will cover more than the bands I want to measure. When I plot the lanes I can´t separate the unwanted band from the one I want to quantify. It seems like the plots separate in the vertical plane (from the picture) but plots everything from the horisontal plane after the same x-axis (am I making any sense at all??).
So my question is: How do I quantify bands of unequal size?

I have also tried to use Scion Image instead, but with that I cannot open the files! (I have a pc and try to open tiff files).
Anyone else having this problem??

Thanks

Hi,

a method consists in selection of all the bands in a unique horizontal rectangle
and then plot the first lane only (see figure attached)

Sebastien

Thank you!