I borrowed a Macbeth densitometer. The manual says its possible to measure densi ty, but its a reflection densitometer. Is it possible to read my negs? My thinki ng is that I put my negs on a light-box and then meter the light trough the nega tives. Is this possible? And has anyone experience with this particular densitom eter. Its a portable reflection densitometer Macbeth RD 1145, of the Kollmorgen Instruments corporation.