Creating Cold Light Tutorial Author - Man1c M0g (http://forums.biorust.com/member.php?userid=1)

Sales and marketing people have known for years that there is an incomprehensible mental link between the quality of light and the human emotions that they create.  Cold light conveys feelings of isolation, loneliness, and emptiness - feelings you'd hardly want from a product, but very useful if you want to exploit perceptions to enhance before-and-after images (eg. in fitness magazines, when hawking health supplements, etc).    Exploring this link with colored lights is an easy approach, but un-necessary given the tools at your disposal with a high resolution photograph and Photoshop!
 

Step 1: Open up a stock image in Photoshop of any size and/or format. If you have a darkly-colored source image you may want to spend a few minutes playing with the contrast/brightness or levels to improve the overall color clarity.

Step 2:  Click on Layer > New Adjustment Layer > Curves. Name the layer as you wish in the dialog box that appears, and press OK. A new dialog box will pop up.  Rather than applying the curve to the RGB composite we are going to edit the Red and Blue curves only.  So, select 'Red' from the drop-down Channel listbox and alter your curve to look like the one I have on the left.

Step 3: Without leaving the dialog box, go to the 'Blue' channel and enter in the curve on the left. Note:   Each image has different curve requirements depending on its composition, so feel free to tweak the Red and Blue curves as needed to suit your own needs.

Step 4: When done, just press OK... and you are done!   Of course, the beauty of this technique is that its non-destructive.  Just go back to the layers palette and double-lick on the curves adjustment layer if you need to make adjustments later. NB.   To compare before & after images, just place your mouse over the image to the left.  The difference is subtle, but very emotionally perceptible!