GR translation: the precisions of light

[Mike Jing]

P208.18-26   Good mornings of good old lust, early shutters open to
the sea, winds coming in with the heavy brushing of palm leaves, the
wheezing break to surface and sun of porpoises out in the harbor.
“Oh,” Katje groans, somewhere under a pile of their batistes and
brocade, “Slothrop, you pig.”
“Oink, oink, oink,” sez Slothrop cheerfully. Seaglare dances up on the
ceiling, smoke curls from black-market cigarettes. Given the
precisions of light these mornings, there are forms of grace to be
found in the rising of the smoke, meander, furl, delicate fade to
clarity. . . .

What does "the precisions of light" mean?  What does it mean to say
light is "precise"?