View source for Determining Percent Purity

#Scan image and save as a tiff file (8-bit not 16-bit) with lanes oriented vertically.
#Open ImageJ either locally or via the webstart applet at http://rsbweb.nih.gov/ij/applets.html
#Using a rectangular box select entire lane.
#Select lane either by selecting Analyze->Gels->Select First Lane or CTRL-1
#Plot lane by selecting Analyze->Gels->Plot Lanes or CTRL-3
#Draw baseline using the line tool.
#If necessary use the line tool to connect peaks to the baseline
#Select peaks using the wand (tracing) tool
#Calculate purity by the area under the peak of interest divided by the area under all peaks combined.