IDAS L+RGB filter sets are designed for tri-color (RGB) imaging and are available in two types of sets:

Type 2 - sharp cutoff filters designed for refractors and other telescopes with lenses

Type 3 - wide band filters suitable for reflecting telescopes (Newtonian, Cassegrain, etc.). The bandpass is tailored to more closely mimic the response of the human eye so that violet is reproduced as we see it.

The bandpasses (for the above filter sets) are designed for astronomical imaging. The passband rolloffs are sufficiently gentle and overlapping to allow intermediate colors (especially the prominent emission nebula lines) to be reproduced so that the elusive goal of "true color" can be approached. All filters except the clear filter include IR blocking.