Thanks for your nice suggest. We are also requiring the supplier to send materials to 3rd party lab for luminous transmittance test and the supplier offer the problem of referenced standard.I suggest sending the dev.'s filed materials to 3rd party lab too since all the dev.'s materials for all trials are qualified, and then take the dev.'s materials' result as reference. Do you you have any other suggestions? Otherway, it's the first case that the special use and quality about this, not willing to but the machine considering the cost now. We will track of the luminous transmittance test results about this materials and their intended uses