The present invention relates to a method and system for determining a lens of a custom color, the method comprising: determining a target colorimetric data set; Providing access to a database containing data representing colors; Based on the data from the database, a plurality of simulated colorimetric data of a lens substrate combined with a determined dye(s) combination, a mixture of composition and amount of dyes, or combined with a multilayer stack according to the determined layer composition and thickness, is obtained. Using a plurality of simulation modules to produce; And color matching a plurality of simulated colorimetric data with a target colorimetric data set to determine a mixture of the determined dyes or one or more combinations of the determined multilayer stack and the lens substrate.