I am copying and pasting this from one of my posts on Texas Photo Forum. I'll try to pull out the stuff that doesn't translate between forums well... hopefully this will help someone. Also- when I work on images I use a Mac so when I use the word Option think Alt.
This set of techniques is almost impossible to show the value of in one short post and I don't have the time or patience to do a lot of writing. My suggestion, if you want a significant amount of detail for how to make the best use of what I am going to write below, is to get your hands on the DVD
Drawing with Light.
The following are my words however the credit for them (not how I present them... can't blame them if I screw something up) goes to John Paul Caponigro and R Mac Holbert (Google them if you don't know who they are, I didn't). I can only hope that I don't misspeak what they have taught myself and others. I spent a week at The Brooks Institute, in a printing workshop, in Santa Barbara, CA back in November. It was hands down the best workshop that I've ever attended.
For the most part this will be about landscape type images however any image that you desire to add depth to... and that has depth that can be enhanced (if it's not there it ain't happening unless you get tricky and add some foreground or background elements) will benefit from the techniques. The techniques are ridiculously simple and quick to use.
Theory (I hope I don't botch this up)
Images are 2D representations of a 3D (or more) world. The challenge in photography is to give the viewer of the image the illusion of depth. How is that done? Take notice of the real world. Things that are far away are darker. Things that are close are lighter. Things that are far away are cooler. Things that are close are warmer. Things that are far away are less saturated. Things that are close are more saturated (that doesn't mean to saturate the crap out of an image btw). To add depth to the image it would appear that the three best tools for that are:
Luminosity (light / dark)
Hue (warm / cool)
Saturation (saturated / desaturated)
How does one quickly and easily use one, two, or all three of these tools? Adjustment layers.
Onward through the fog-
Open an image
Some would say do the Shadows and Highlights adjustments, spotting, etc on an adjustment layer but unless I'm planning to save the un-flattened file for printing later I do them all on the background layer.
Once that's out of the way, with the topmost layer selected (in case you do S&H on it's own layer), hold down the option key and click the Create New Adjustment Layer icon (black and white circle on the layers palette) and select Curves. Give the layer a name (naming becomes important later). I use Global Adj- L (L for Lightness, H for Hue, S for Saturation) on the first one because that is the mode that should be used first. Select Lightness in the Mode drop down. You'll get the curves dialog as well as an adjustment layer and mask above the layer that you selected. With the
MASK selected, make sure it's selected by clicking on it once, go to the gradient tool, select a linear gradient (change that up on the task bar. Default, I think, is linear), hold down the shift key, drag the gradient from top to bottom.
BTW- Using adjustment layers keeps the file size down.
Bear in mind that as I type this I'm thinking about landscapes. Something with a defined foreground / background element. You can pick this apart and throw all kinds of what if's at it if you want to... but you'll miss the intent of some very powerful tools if you do that. Using masks, the gradient tool, and the Luminosity, Hue, and Saturation modes are very simple and fast tools for enhancing most images. The gradient does not have o be applied vertically. Don't hold the shift key down and drag it at an angle. Option click the mask and then hit Command T to open the Free Transform tool to the mask. You can tweak the gradient by selecting the mask and using Image-> Adjustments-> Curves to add a curve to the mask. The mask can also be adjusted by Selecting the Mask Tab and using the Density and Feather sliders to change the mask. Sometimes I use a contrast mask rather than the gradient tool (see the other post for contrast mask). Luminosity, hue, and saturation are all great tools for creating separation. Masks are your friend :smile:
A quick note on masks. Black nulls the effect of the adjustment. White allows 100% if the adjustment through. Varying shades of gray varies the amount of the adjustment. With that in mind, you can see that painting these colors (
with the mask selected, not the image) gives you almost infinite control over how much you adjust an image. FYI- Per Mac Holberts suggestion I now use a soft round brush set at 100% opacity and 6% flow to paint on my masks. The control you get is much finer than with an opacity setting as it works more like an airbrush so that the longer you stay on an area the darker or lighter the affect gets.
Back on topic- Now that you have created a gradient mask on your layer take a look at your image and the mask. To see the mask hold down the option key and click on it. It helps me to see the mask but I think that once I get used to painting on the image I won't need that anymore. Option click again to return to the image. If the mask is inverted, for instance if you want to darken the sky but the black part of the mask is at the top, just hit Command I to invert the mask. Now adjust the curve to give the effect that you desire. Very often I will drag this layer to the create a new layer icon, invert the mask and change the curve so that I lighten the foreground. It's not always effective but it works enough that I use it frequently. If it doesn't work drag it to the trash can. You can also paint in or out, by selecting the mask and using a brush to paint black or white over the area you want to include or exclude. If you use dual luminosity layers as I've outlined here it's not a bad idea to select both of them and hit Command G to group them. Name them G Luminosity or something so that you know its a global luminosity correction. Once they are grouped you can toggle the "eye" and turn them off and on as a group to see the overall effect or expand the group and turn them off and on selectively.
If the image needs it, do the same thing only use the Hue and Saturation modes. It's important that the layer stack is in the proper order. Luminosity below hue. Hue below Saturation. Group the Global L-H-S layers so that the combined effect can easily be toggled off and on. Name your groups! As you use the techniques more and more you can expand them to Local L-H-S adjustments and mask specific areas (down to the eye or hair level) and it's important to know what you did where. When you move from Global to Local it's important that the Local Adjustments are on top of the Global Adjustments. The sharpening layer would be the topmost layer.
This workflow is for tweaking an image to create the best print possible. However, You can flatten and save for web posting and you will see a good result from it. It sounds complicated but in actual use it is a very quick process. Much quicker than anything else I've learned in the last 5 years.