Get Dynamic Lighting After the Fact with Photoshop
Adobe Photoshop is a wonderful post production tool for photographers, and with this program you can accomplish more than just your basic touch ups. It is possible to achieve dynamic lighting in Photoshop after your shoot, you just need to know how to make the program work for you.
Step 1: Exposure
Depending on how you wish to adjust the lighting, exposure is a good place to start if you plan on making large adjustments. This will be the first of your broad strokes.
At the top, select 'Image'->'Adjustments'->'Exposure.' You'll be able to over-exposure or under-expose the image in these controls. While you won't be able to retrieve information that might have been lost when the image was taken due to poor exposure, you can still adjust and off set the balances to make the overall image brighter or darker.
Step 2: Brightness/Contrast
Once the exposure has been adjusted, you can use brightness/contrast to hone in on the settings you want.
Select 'Image'->'Adjustments'->'Brightness/ Contrast.' Adjust the settings until you find a balance that you like. What's great about CS4 is that you can see the adjustments in realtime without rendering so if you don't like it, you can just hit cancel.
Step 3: Hue/ Saturation
Light affects the tone of your colors, and with hue/saturation you can help adjust the color to your liking.
Select 'Image'->'Adjustments'->'Hue/Saturation.' Tweak the settings until you find a balance that suits your needs.
Step 4: Shadow/Highlight
The final broad stroke in your lighting portrait is the Shadow/Highlight feature which tweaks the overall brightness of the image. This tool specifically targets areas that are darker or brighter than the rest of the image.
Select 'Image'->'Adjustments'->'Shadow/ Highlight.' Using the image adjustments gives you overall control over the brightness and color of an image. They make big changes quickly and have great influence over your photo. But, the real artistry and precision occurs in Photoshops other functions, specifically with layering.
Step 5: Separate the Subject
The real magic of Photoshop lies in mastering the use of layers. Layers, piled onto each other, are what creates a dynamic image. Using the magnetic lasso tool, you are going to drag the mouse around your subject. Take your time doing it. This steps takes time and practice. The slightest wrong movement could cut off a chunk of the subject's hair, making you start over again.
Once the subject is encircled by the magnetic lasso, switch to the selection tool and slightly move the subject. You'll notice a blank spot where they once were. You just made a new layer.
Step 6: Create Light
Make a new layer and position it between the subject and your background. You may want to temporally turn of the view of the subject so you can concentrate on your work. Apply a gradient overlay and a pattern overlay on the new layer. You're going to make everything in the new layer transparent, except for a gradient circle that will be the color of your light.
Once you position the circle in the black spot, make adjustments so
there is some nice glow and fall off. Then make your subject visible
again and position her over the circle so that only the fall off is
visible. You may want to add a blur filter to the gradient to get the
fall off effect you want. You now have backlight.