Darkle \Dar"kle\ (d[aum]r"k'l), v. i. [Freq. of dark.]
To grow dark; to show indistinctly. --Thackeray.
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Tinct \Tinct\, v. t. [See Tinge.]
To color or stain; to imblue; to tint. [Archaic] --Bacon.
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He gathers shadow and shifts in the color spectrum. It makes one hard to see. When Patrick is trying to capture his image, he keeps shifting in the spectrum, which would be tough on a painter.