It's sometimes useful, e.g. when spot-checking the contents of a filter wheel, to have an idea of the visual colour of the light transmitted by a given filter. The perceived colours of a selection of ING filters (when illuminated from the other side by white light) are listed below (colour of text is indicative only).

Narrow-band filters:
The first column gives the approximate central wavelength of the filter in A.

 3727  black (i.e. no light detected by eye)
 3772  black
 4285  blue, with violet tinge
 4691  blue
 4770  blue
 4890  greenish blue
 5009  blueish green
 5175  green
 5340  green
 5900  yellow
 6240  orange
 6303  orange red
 6565  red
 6700  red
 9077  black
10839  black

The human eye detects light over a wavelength range of approximately 4000 - 7000 A. Within this range, monochromatic light is mostly perceived as blue, green or red, with relatively narrow ranges of wavelength being perceived as yellow or orange.

Broad-band filters:

Sloan u  violet (faint)
Sloan g  turquoise blue
Sloan r  orange
Sloan i  red
Sloan z  red (faint)

Harris B  blue 
Harris V  green
Harris R  orange
Harris I  red

Bessell U  violet (faint)
Bessell B  blue
Bessell V  green
Bessell R  orange
Bessell I  red

GG495A  yellow 
GG395A  white