wavelength

vector of increasing numeric values

the physical unit is always nanometers

when organization is not 'df.col'

step.wl

difference between consecutive values in regular wavelength

usual values in colorimetry are 1, 5, 10, and 20 nm; but there are others.

when wavelength is regular
(an arithmetic sequence)

quantity

a string; for valid values see Table 2.1

the quantity determines the type

always

specname

a string; the name of the single spectrum

when organization is 'vector'

metadata

<user-defined list>

unstructured miscellaneous data that the user may find useful

always

sequence

a list of other colorSpec objects

when the object was returned from product()

calibrate

a list of calibration data

when the object was returned from calibrate()

emulate

a list of emulation data

when the object was returned from emulate()