It is generally not considered transformative enough to avoid liability for copyright infringement to simply change the colors of an existing photo. The owner of the copyright in the original photo, or their authorized licensee, has the exclusive right to create derivative works, which includes altering the photo in any significant way. Therefore, changing the color of a copyrighted photo could potentially be considered infringement, assuming the original has all rights reserved. It is important to note that the specific circumstances of each case may affect whether or not a change in color would be considered infringement.