Compare, contrast, collate mean to set two or more things side by side in order to show likenesses and differences.
Compare implies as an aim the showing of relative values or excellences or a bringing out of characteristic qualities, whether they are similar or divergent; contrast implies as the aim an attempt to emphasize their differences; thus, one may compare the movement of the Odyssey with that of the Aeneid to arrive at their distinctive qualities; one may thereupon contrast the buoyancy and rapidity of the one with the stateliness and dignity of the other.
One object is compared with another, as above: it is compared to another when it is formally represented on the basis of a real or imagined similarity as being like that other; thus, Pope compares Homer with (not to) Vergil; he compares Homer to (not with) the Nile, pouring out his riches with a boundless overflow, Vergil to (not with) a river in its banks, with a gentle and constant stream.
Collate suggests a minute or critical comparison in order to note points of agreement and divergence; it applies especially to the minute comparison of books and manuscripts containing different versions of the same work for the sake of ascertaining or establishing the correct text.