How can I extract the CLim color id of an imagesc plot?

For an imagesc plot, I have set the color limits of the cells between 0 and 100. I would like to know what the color id of each cell is, whether by reverse calculation or extracting the data from the plot. I know for a fact that it is not a linear scale, this is because my top two values are 33200 and 833, meaning that the second value would be around .28 of the nominal if we scale everything between 0 and 1 for color id. Yet, numerous values end up being of the same color. I would like to know how clim determines based on the cell value what color it takes up.