I'm new QC chemist who has inherited a lot of bad methods that I'm trying to clean up. Its also been awhile since I've had to deal with hplc. Some methods just need to be tweaked by assigning a new wavelength for the detector.

Now, when I open the isoabsorbance plot I'm able to read the contour plot just fine. It's the plot below this that's throwing me off: what do the different colors mean? I'll go out on a limb and say that blue is the peak I captured, black is the calculated difference based on a new wavelength, but what is red?

Also, any info on what the plot above the cotour plot is would be greatly appreciated.