Standard values for the BAND column are:
for the UBV(RI) system: 'U', 'B', 'V', 'R', 'I'
for the 4-color system: 'u', 'v', 'b', 'y'
for the H-beta system: 'betaW', 'betaN' (for Wide and Narrow, respectively)
for red-leak filters: the name of the main band followed by 'RL'; e.g., 'URL', 'BRL', etc.
for ``neutral'' filter combinations: the name of the band, followed by 'ND' if only one value of attenuation is used, or by 'ND1', 'ND2', etc., if more values are used
for any opaque position: 'DARK' for a single detector; or 'DARK1', 'DARK2', etc. for multiple detectors
Notice that each distinct type of measurement counts as a separate band entry, including measurements made with different neutral-density filters, red-leak, and dark measurements. For example, a one-channel photometer with a filter wheel that measures U, B, V, and the red leak in U, plus a slide containing open, opaque, and two neutral-density filters would have [4 filters (2 ND + 1 clear positions = 3 different intensity measurements) ] = 12 different rows, plus a 13th row for the dark measurement. The combinations of red-leak filters that involve ND filters should be named with the RL before the ND -- e.g., URLND1. For more details, see the examples in subsection I.5.7, ``Sample instrument files''.
The column named NBAND contains an integer used for cross-referencing. An I4 format is convenient. Normally, this is the reference column for the whole table file.