here is some Opple4 data with Lee Filters
clic pic to see source:
the good:
imo the data looks pretty consistent in terms of the change in DUV, and the CRI R9 seems pretty consistent
also note that maukka saw a duv drop of 0.0040 from using a 1/8 minus green… so imo, the duv measured on the LM4 is very much IN the ballpark…
clic pic to see source:
backstory… the Lee 804 has a light loss of 16%, the Lee 1/8 minus green has a loss of 13% making them roughly equivalent imo…
the bad:
it also confirms caanga’s observation that the spectrum plot does not change