Provided are novel methods and systems for setting up ranges of optical inspection parameters. These ranges may be later used for inspection of photovoltaic cells for discoloration, for example. A set of values corresponding to an inspection parameter, such as hue, saturation, and intensity, is obtained from a set-up image. The image includes multiple set-up areas, e.g., a defined group of pixels, wherein each set-up area is assigned a corresponding value in the set. A test image is then constructed from multiple test areas that are also associated with the values in the set. Each test area is assigned a color from a set of user defined colors based on the corresponding value and user defined ranges. A user interface includes both a range diagram and test image, which are used to adjust the ranges in the diagram that result in modification of the test image. Adjusting is repeated until the test image meets predetermined criteria.