Method for determining a characteristic of a consumable

A method for determining at least one characteristic of a physical resource used in a physical resource consuming apparatus having a controller, an illumination source operably coupled to the controller, a removable component comprising the physical resource, and a graphic applied to the removable component, with the graphic, removable component, and physical resource defining a multiple layer composite, the method comprising:

• illuminating, with the illumination source, a first depth of the composite and determining a corresponding first reflectance of the first depth of the composite;
• illuminating, with the illumination source, a second depth of the composite, which is deeper than the first depth, and determining a corresponding second reflectance of the second depth of the composite;
• and
• determining, with the controller, can at least one characteristic, other than the first and second reflectances, of the physical resource from the first and second reflectances.