This was information I found on the Etsy forums about improving product photos. I am always interested in ways to improve my photos so I thought I would share Allison's quick fix. This post was written by Allison of Zipper8Designs.
"I've been taking new photos of my products, and even though I bought a daylight bulb, they are coming out a bit pink-yellow-ish. So I've been editing them in photoshop, and found a great quick fix, so I thought I'd pass it along and see if I could help some other people.
Oh, and my photos are on a white background, which is why this works. Just putting that out there.
When you open the photo in Photoshop, go up to the Color Balance (Image-Adjustments-Color Balance). Then you have to make sure you switch from effecting Midtones, to Highlights. This way the color balance change will primarily effect the white background, and not the color of your actual product. (If you need to tweak the color of your product, you can play around with changing the Midtones and Shadows toggles too.)
Then, simply increase the top slider towards Cyan, and increase the bottom slider towards Blue. You need to move both sliders because they balance each other out, towards a purer white."
You can find out more about Allison on her Blog at: http://zipper8musings.blogspot.com