Vertical remission densitometry for the evaluation of nontransparent samples

Gels dried onto filter paper or their blots on membranes are not suitable for densitometric evaluations in the transmission mode because these samples are nearly nontransparent. By scanning in the remission mode, evaluation with good results is possible. Data acquisition by a computer-controlled high speed scanning photometer and digital image processing affords a spatial resolution and accuracy similar to that in the transmission mode. The signal-to-background ratio decreases by 10-30% depending on the smoothness of the support.