X-Rite's scanning densitometers, models 390 and 391, are able to consistently and reliably measure films with a D-Max of 4.50D optical density. Note however, that recent developments in film technology have resulted in photographic media that may exceed 5.00D. X-Rite's scanning densitometers may or may not be able to measure these extremely high-contrast materials. X-Rite's Engineering Team has developed a product line enhancement for these densitometers that will allow users to read high-density film without repeated "Invalid Reading" errors. For more information on this product enhancement, select the Additional Information on the bottom of this page.