This is a list of relevant websites that you might find useful and informative as you conduct your research - websites include: histories of art, examinations of color and color theory, and general graphic design/art websites and blogs.
Remember, do not take images from websites, unless you have the permission of the creator of those images, know the images are public domain or are for educational purposes, or can properly cite the original creator of the images you want to use. Please refer to the using images and the citing sources pages for more information.