A system and a method for improving visibility of newly decaying or carious tissue are described. Light having a lower peak wavelength (such as 405 nm) illuminates dental tissue, and an image is captured. Light having a higher peak wavelength (such as 450 nm) then illuminates the same dental tissue, and a second image is captured. The images are aligned, and an output image is created based on at least one of the first image and the second image, modified in certain areas as a function of the relationships between the red values of the first image (R1) and the second image (R2) at that location and the green values of the first image (G1) and the second image (G2) at that location. The function may use the ratios R2:R1 and G1:G2, such as a function of the product of those ratios, to determine the color adjustment that is applied.
