I've read through this thread twice now and don't remember half of the tips that have already been done so I hope this isn't duplicated.
While the new max 2.0 has some great new tools for adjusting color, let's not forget this simple way to change the overall tint of a photo/background, etc.
Take a paper scrap (such as the different color construction papers included) and bring it into the layout.
Resize the scrap to the same size as the photo/background etc.
Then, either move it on top of the photo and decrease the transparency of the scrap
or
move it behind the photo and decrease the transparency of photo!
Combined with changing the color of the scrap with the new adjust color options, the possibilities are endless for getting the tint just right.
This example shows how I changed the tint of the original photo using this method (with a blue scrap) and then using it as the background for the layout.
Bookmarks