1. A method for identifying defects in a wafer with an inspection tool comprising: capturing, using an electronic image capture device of the inspection tool, a grayscale image set of the wafer by: illuminating at least a portion of the wafer with a blue wavelength light and capturing a first grayscale image; illuminating at least a portion of the wafer with a red wavelength light and capturing a second grayscale image; and illuminating at least a portion of the wafer with a green wavelength light and capturing a third grayscale image; storing the grayscale image set into a computer-readable memory; determining, using a processor in communication with the computer-readable memory, a residual signal in each of the images of the grayscale image set based on a combination of the images in the grayscale image set; subtracting, using the processor, the residual signal of each image of the grayscale image set from each image of the grayscale image set; and identifying, using the processor, a defect in the wafer based on the subtracted grayscale image set.