Monday, October 18, 2010

Image Adjustment Part 2: Shadow/Highlights

Please contact me via email:

“Creativity is allowing yourself to make mistakes. Art is knowing which ones to keep.”   — Scott Adams

Before the introduction of the  Shadow/Highlight Adjustment  in Photoshop CS in 2003, it took a lot of moves to make an underexposed image usable.  False Profiles  (see Studio Note Assign/Convert Profile) were usually the starting point followed by channel blending and then a healthy dose of Curves. If you worked at it long and hard enough you could salvage almost any image and make the client — and yourself — very happy. No need to reshoot or start from scratch or wonder when you’ll ever catch that great sunset again.

Those days, for the most part, are long gone although I still regularly use channel blending, occasionally  False Profiles  and always use  Curves  to adjust images. Thanks to the  Shadow/Highlight Adjustment (SHH)  command complex image manipulations are performed in the background using a simple front end dialog for getting the job done quickly. The Shadow/Highlight command quickly became a favorite with photographers, photo retouchers (like me) and pre-press professional for its amazing ability to bring out details in the shadow and highlight areas of an image that were too dark or too light to see. In fact, the Shadow/Highlight command is so good at bringing out image detail that I apply it to just about all of my images, even those that at first glance don’t seem to need it.

Shadow/Highlight  is only available as a standard image adjustment, not an  Adjustment Layer.  Standard image adjustments are permanent so its a good idea to to protect the original image. So before doing anything (and you should ALWAYS do this first before working on ANY image) duplicate the original image by click-dragging the  Background Layer  onto the little dog-eared icon at the bottom right of the  Layers Palette. You now have new layer named by default  Background Copy.  Double-click the name Background Copy. It will turn a light blue color and you can type a new name right over it. I usually name the layer add  SHH at the end.

Photoshop Layers Palette. The New/Duplicate Layer icon is circled in red.

Now open the  Shadow/Highlight Adjustment  window by going to >Image, >Adjustments, >Shadow/Highlight and you’ll see a window that looks like this:

Photoshop Shadow/Highlight Adjustment default window settings.  They will produce an unsatisfactory adjustment and need to be changed.  Start by checking the Show More Options box.

Shadows  value of 50% is usually way too much to start with and will result an unnaceptable image adjustment. A simple change to the default settings is all that’s necessary to quickly produce a significantly improved image. Start by checking the  Show More Options  dialog and you’ll get an expanded window that looks like this but with default Photoshop default settings instead of my settings that you see here.

Photoshop Shadow/Highlight Adjustment with new values replacing the default settings. These settings will give you a much better starting point for producing a great looking image and you can adjust them as necessary for each image. Click Save As Defaults after resetting the numbers and these settings will be permanent whenever you call up the Shadow/Highlight Adjustment .

The expanded version of the Shadow/Highlight dialog box appears a bit intimidating at first, especially since the simplified version contained only two sliders, but not to worry. The expanded window is divided into three sections — two of the three sections,  Shadow  and  Highlight,  are exactly the same with each group containing three sliders to help bring out shadow or highlight detail in the image. Below the Highlights section is the Adjustments section which offers a few more options for adjusting the image.

The first slider,  Amount,  is straightforward enough. It controls how much you want to open up the shadows, making them appear brighter. After you become more familar with what the various setting do to alter the image you can just punch in the numbers. But for now draging the sliders is the way to go and you’ll see the results on your image in real time as you make your adjustments. Drag the slider towards the right and you’ll recover more shadow detail. Rarely, if ever, will you need to set the amount past 50 as your image will start to look weird and unnatural. start  If you drag it too far, you'll brighten the shadows too much. That’s why I start with a value of 25 — to see how it looks then go up or down as necessary from there. Every photo is different so just keep an eye on your image as you drag the Amount slider and set it to whatever looks good for now.

The next setting is the  Tonal Width  slider. This determines the range of tonal values that will be affected by the adjustment. Lower numbers affect only the darkest areas (values) of the image. Moving the slider to the right will expand the range to include more of the midtone values. There’s no right setting so just experiement to see what looks good for your particular image. A good starting point for  the Tonal Width  setting of 50%.

The last slider in the group is the  Radius  setting which determines how the other two adjustments you just made will blend in with the rest of the photo. A low Radius value will make your image your appear noticeably flat with harsh transition areas between the adjusted and unadjusted areas of the image. I think a higher Radius value works best so start with a value of 90 pixels and adjust up or down from there. After setting the Radius value you may want to go back and re-adjust the first two settings — I often go back and forth several times before I see something I like.

The  Highlights  group works the same way as the  Shadow  group. I tend to go easy on the highlight settings as overall image contrast can easily be compromised so minor changes often help. My new settings are: Amount 6%; Tonal Width value of 50% and a Radius value of 90px. The settings that work best on your image will most likely be different but these settings deliver a good starting point.

The last group,  Adjustments,  help to restore color saturation and midtone contrast that might have been lost after making the new Shadow and Hightlight adjustments. The first slider,  Color Correction,  is not really a color correction at all, but a saturation adjustment.  Move it to the right and the color saturation increases; to the left the color is neutralized. The  Midtone Contrast  slider is used to increase midtone brightness values giving the image a bit more “punch” if desired. Leave the default  Color Correction  alone and setting  Midtone Contrast  value of +6 is a safe start.  Black Clip  and  White Clip  specifies how much of the shadows and highlights will be clipped (reset) to the new Shadow (0) and Highlight (255) colors in the image. Larger values means greater image contrast so don’t set them too high or you’ll be right back where you started, more or less.

Lastly, after resetting the numbers, click  Save As Defaults,  and the new settings become the default settings. Below is an image before and after these new default settings have been applied. Simple, painless and no need to adjust further. At least as far as image  Shadow  and  Highlight  are concerned. Of course, there will always be the need tweak an image further and it will usually be necessary to make a REAL color correction, most likely by applying  Curves,  and then the image will require  sharpening.

Left: Original image from digital camera sRGB default color space.  Right: Same image with Bruce RGB Assign Profile and new Shadow/Highlight Adjustment applied.

That’s for Image Adjustments Studio Notes parts 3 and 4.

See you soon!


No comments:

Post a Comment