Wednesday, February 23, 2011

Quick Use Of The Multiply And Screen Blend Modes

Take a look at today's image.  You can see the contrast range is pretty extreme.  We have bright sunlight and deep shadow.  The trick is to take control of the extremes and bring the shadows up and the highlights down.  There are many ways to accomplish the task, but there is a technique I use that gives all the control you can possibly ask for.  The first thing was to go to HDR Pro in Adobe Photoshop CS5 and make a reasonably natural looking HDR image.  That got us part of the way.  I wanted to keep the scene looking fairly straight, not the wild side of HDR.  The image was still contrasty.  It needed selective attention in at least three areas.  The first thing to do was to make a couple Alpha Channel Masks.  One of the group of people to the left of the pole.  Another for the umbrella canopies and a third getting the entire group.  A couple secondary masks were made for the woman on the left's chin and the Harley Davidson patch on the man's jacket.  To find out how each mask was used, hit the "read more".

The first step was to maximize the color saturation using individual (Red, Yellow, Green, Cyan, Blue, and Magenta) Hue/Saturation Adjustment Layers. The method I use is to create a separate Adjustment Layer for each color. I'll just go down the list found in the dropdown near the top of the dialog box that shows "Master" by default. I'll take each color and raise the Saturation to 100%. After highlighting the Amount I'll Hold down the Shift Key I'll tap the Down Arrow Key. This bring the amount of Saturation down ten points per tap. Without the Shift Key the reduction would be one point at a time. You'd have to have amazing eye to see a one, two or three point change. Ten points, you can see the differences piling up. The only thing I was interested in was the umbrella canopies. Everything else in the scene still looked pretty neon when the canopies looked the way I wanted them. I tossed the Layer Mask that came with the Adjustment Layer in the trash, switched to the Channels Panel and Ctrl, clicked on the canopy Alpha Channel Icon, and flipped back to the Layers Panel. Hitting the Add New Layer Mask icon at the bottom of the panel produced a Mask with the selection in place. If you need to, hitting Ctrl I (eye) will invert the Mask. The canopies were now the right shade of color and the rest of the scene returned back to neutral.
A copy of the overall scene was put into a Multiply Blend Mode, darkening the scene and throwing the group under the umbrella much too dark. I went over to the Channels Panel and Ctrl clicked on the Alpha Channel icon showing the group of people in the shade. Clicking the Add New Layer Mask icon at the bottom of the Layers Panel resulted in the overall scene being tined down and the "shadow group" staying brighter. The same Mask, inverted, allowed the "shadow group" to be changed to a Screen Blend Mode, making it brighter.

The woman on the left's chin was much too bright, so a Bland mode change to Multiply with a Mask of only her chin toned the chin down. The Harley Davidson patch on the man's jacket was too blue, so using a Mask of the patch a Hue Saturation Adjustment Layer was used to Desaturate the patch by about 50%.

Each intermediate step was made into its own Smart Object. Using Smart Object allows you to go back to any point in the post processing and fix whatever flaw notice in the end image. Smart Objects should be made a standard part of your workflow.