How long does sun fade a photographic picture that I got developed from a local Target store?

I need to see that if a photography picture from target will fade in the sunlight for 4 hours. I know that visible fading may not occur, but few pixels may be changed otherwise. I am using a photoshop to detect the number of pixels of color that changed. So, my question is that is it possible for a picture from Target to have faded very very little (unnoticeably) in the sun for 4 hours? thanks :]How long does sun fade a photographic picture that I got developed from a local Target store?
I'm not a photographer but i'd say it definitely could be effected in 4 hours...How long does sun fade a photographic picture that I got developed from a local Target store?
Not sure what we are talking about: do you WANT to see fading for an experiment? If so, lay it flat out doors: window glass blocks some UV which will decrease fading. You could cover one side of the picture with black paper to compare the differences. Remember: in the northern hemisphere you'll see far less fading this time of year than you would at mid-summer.