Check out the rules of this contest:
Quote: We do not accept digitally or otherwise enhanced or altered photos, except for those entered in the Altered Images category. Minor adjustments, including spotting, dodging and burning, sharpening, contrast and slight color adjustment or the digital equivalents, are acceptable for all five categories. If our judges determine that a photographer has altered his or her photo, they reserve the right to move the photo to Altered Images or to disqualify it.
Read more:
Photo Contest Rules | 9th Annual Photo Contest | Smithsonian Magazine
Quite unclear to me as to how far you can go with the "contrast and slight color adjustment or the digital equivalents". They don't accept enhanced photos, but minor adjustments are ok??
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