The color of a photograph can take you back in time, create a mood, or make your work look amateurish.
Instagram, in a homage to both the Kodak Instamatic and Polaroid cameras, confines photos into a square shape. It lets you apply a filter and combined with edge effects and the square format can make a photo taken today look like a nostalgia piece. You can make it look like the 1920s, 1950s, or 1970s. The reason for the transformation in time is the photo triggers memories for those who lived during this time or for those people who have found a shoebox or old family albums and looked through the photos.
On the other end of creating a mood is the amateur look. This is where you have color caste to your photos. If under fluorescent light they may look green. While inside with incandescent lights you have an orange effect.
If you mix flash with the available light you may have proper light on the objects closest to the camera and then the background has a color shift.
Look for Upcoming Part 2 and 3.