One way of dealing with this is to query {HEAD ~ the User} regarding the source of the environmental light by a software application operating at {TAIL ~ the host computer} coupled to the display 
One way of dealing with this is to query { HEAD ~ the User } regarding the source of the environmental light by a software application operating at { TAIL ~ the host computer } coupled to the display
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH