Thanks for your response. We're working on a database of information about gels from multiple vendors, each of which provide slightly different stats about the gels that they sell. Overall transmission is something that two of the three vendors we're including provide, but the third doesn't...
My boyfriend and I are trying to wrap our heads around some charts describing lighting gels used in theater, like these:
http://rosco.com/images/filters/roscolux/3315.jpg
http://rosco.com/images/filters/roscolux/4830.jpg
Each has a chart with a spectral transmittance curve on it, and...