Some Random Filters from eBay

I picked up some ASI FW1000 filter wheels from eBay that were going cheap. One of them was fitted with unspecified filters. Given that a number of the FW1000s on eBay are from Genome Analyzers I suspected these would be the same as those I already have. But they were completely different.

So I stuck them up against my Xenon light source and looked at the spectra… the plots are shown at the bottom of this post. Two of the filters have spectra that seem easy to interpret. 1000736 69799 (A) seems to be a band pass between ~550nm and 570nm. And 1000735 69790 (B) seems to be a band pass between ~576nm and 655nm.

The other two, I don’t understand. 1000732 69780 is a bandpass over roughly the same range as (A) above. But seems to strongly attenuate the signal. 1000733 69768 has some kind of peak around 660nm? But it’s much less clear.

Googling around I found the following reference to filters with similar serial numbers:

These three filters match the recorded spectra well, but what exactly 1000732 is doing is less clear to me. Shame the documentation doesn’t list the manufacturer, which might yield more details…