INGRID has two filter wheels and a pupil wheel, the current configuration of which is given below. Filters are inclined by 5 degrees in order to suppress reflections in the image. The green commands explain how to move a wheel independently of the others.
All filters have been purchased in collaboration with the Gemini filter buying consortium (headed by Alan Tokunaga, see their specifications).
The filter transmission curves given below were obtained at room temperature (~293 K) and at an incident angle of 0 degrees. The transmission curves of the narrowband filters in the second filter wheel depend most on the angle of incidence (5°) and on the temperature (77 K, the colder the bluer). Therefore, the measured transmission curves were extrapolated from 0° and 293 K ("warm") to 5° and 77 K (labeled "cold"). The extrapolation was done using this prescription based on the measured data. For the narrow band filter transmission curves, both the warm and the cold data are shown for better comparison.

Overview of INGRID K-band filter transmissions
Overview of INGRID broad band filter transmissions.