Which preposition to use with individualize

by Occurrences 2%

The bird flies by balancing itself against something else; the mountain is emphasized by the valley; and one color is brought out and individualized by another.

from Occurrences 1%

Will you name a day in the same or coming week that we can come to you in the morning, for it would plague us not to see the other two of you, whom we cannot individualize from you, before you go.

Which preposition to use with  individualize