How does it work: A scanned image of the electrophoresis gel is taken. The position of the bands and intensities of the band must be an accurate representation when scanned into an image compared to when the bands were contained in the gel. One must also make sure that the scanner extracts accurate image intensity. To test this a photographic gray scale image with its known optical intensity is used in comparison to the measured optical intensity. If the optical intensities are nearly the same then the densitometer is ready to use.
How does densitometry analyze gel electrophoresis: For the gel to be analyzed and obtain a density profile for each lane. The software will analyze the intensity values for each pixel in each row of the lane. As the intensity values are found a pixel value is generated for each of the lanes which will yields the sum of the density profile. After the density profile is obtained the software finds the peak locations, peak areas, and associated background values. Each of those results correspond to each band in the lane. Once all the density profiles for the for each of the lanes have been obtained the results are displayed on to a spreadsheet[12].