The most common and most likely answer to this crossword clue is the 8 letter word SPECTRAL
I've seen this crossword clue in Independent
S
P
E
C
T
R
A
L
More clues leading to the result SPECTRAL
- Insubstantial small muscle lacks oxygen
- Ghostly second muscle wanting nothing
- Ghostly sort of crate put in small place
- Insubstantial small muscle, one failing in test
- Casper, sadly getting tense, left – like a ghost
- Small muscle, starved of oxygen, exhibiting range of colours
- Phantom PC alerts crook
- Various carpets, fifty covering a range of colours
- Start to suffer in the chest when dropping round, appearing ghostly
- Like shade from colour ranges with finish of eggshell
Buddy explains!

The straight part
We know that "covering a range of colours" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case covering a range of colours = spectral.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does SPECTRAL mean?
SPECTRAL adjective- Of, or pertaining to, spectres; ghostly.
- Of, or pertaining to, spectra; classified according to frequency or wavelength (of light etc)