In this paper, by William Jensen (Dept Chem, University of Cincinnati) on Newton & Lucretius, he details the introduction of Epicurean atomism into renaissance intellectual life:
Though the manuscript of the epic poem, On the Nature of Things, by Lucretius, was ﬁrst printed in book form in 1473 and in many subsequent editions, it was not until the 17th century that it began to impact signiﬁcantly on scientiﬁc thought...Sir Isaac Newton was a second-generation participant in this revival of atomism and so could build upon the earlier atomism of such 17th Century writers as Pierre Gassendi, Walter Charleton and, especially, that of his older British contemporary, Robert Boyle.
Whether Newton was also directly exposed as a student to the famous poem of Lucretius is not known. However, by the 1680s, when he began seriously writing the Opticks, he had almost certainly read Lucretius in the original, since among the surviving books of his personal library is a 1686 Latin edition of De rerum natura, which one Newtonian scholar has described as “showing signs of concentrated study” (i.e. numbering of lines and dog-earing) . Likewise, the Scottish mathematician, David Gregory, reported a conversation with Newton
in May of 1694 in which Newton stated that he could demonstrate that : "The philosophy of Epicurus and Lucretius is true and old, but was wrongly
interpreted by the ancients as atheism."
He then details various analogies between Epicurean atomism and ideas of density, porosity & rarefaction, finally he points out that
In the Opticks Newton’s interest in the question of the relative porosity or degree of rarefaction of materials was driven not by its possible relevance to questions of hardness, ease of melting, or degree of chemical reactivity, but rather by its possible relevance to how matter interacted with light. Like Epicurus, Newton viewed light as being composed of very tiny, rapidly moving particles, and he was interested in how the porosity of a body was related to its ability to transmit, reﬂect, refract, and/or selectively absorb these particles of light.
The evidence looks plausible, but it appears that it the influence of Democritus is not direct, but through Epicurus and mediated by Lucretious. In particular he was most probably unaware of the eidola of Democritus, and used the particle model of light of Epicurus.
 J. Harrison, The Library of Isaac Newton, Cambridge University Press: Cambridge, 1978, item 990, p. 183.
 B. J. Teeter Dobbs, The Janus Faces of Genius: The Role of Alchemy in Newton’s Thought, Cambridge University Press: Cambridge, 1991, p. 216.
 H. W. Turnbull, Ed., The Correspondence of Isaac Newton, Vol. III, 1688-1694, Cambridge University Press: Cambridge, 1961, p. 338