Photo Sharpening Techniques

Today’s Photo Tip: How to Use Sharpening Tools. Most photo editing programs’ sharpening tools act on picture contrast. Boosting contrast usually makes a picture appear sharper. One of the disadvantages in sharpening digital pictures is that the filter is nondiscretionary; meaning that it will sharpen the bits that you don't want sharpened, including digital noise and other imperfections. As there are no "perfect" settings that one can offer, sharpening takes practice. First off, you should always try to start with a focused image. Sharpening will not “focus” a poorly focused picture. FOCUSING TIP: When in Shutter (S) or (M) Manual modes, select the fastest shutter speed possible and use the camera's Auto Focus Lock (AF) feature. NOTE: Two things to remember when sharpening images: (1) Injet prints require less sharpening than newsprint. What may look great on a computer screen, may translate to a much poorer looking printed copy of the same image. (2) Once Unsharp Mask effects have been added to the file (saved), it's impossible to remove them. Because of this, you should always work on a “copy” of the original image. Most photo editing programs offer more than one option for sharpening your images. This often makes it difficult to decide what you should be using to obtain the best result. Below is a description of the most common selections and what they accomplish. Remember, whenever applying any sharpening effect you should always zoom in to 100% so you can more accurately view what is actually taking place. Clarity: The Clarity filter is usually a one-button filter used to add a quick bump in both contrast and image sharpness. It automatically adds changes to both of these at the same time. Sharpen: This option applies a preset contrast boost to an automatically selected range of pixels. Sharpen More: As its name might suggest, this option simply applies a stronger boost than Sharpen. Though easy to use and apply, these three options provide very little control over what gets sharpened. Probably the most common, and most used of the sharpening tools, is the Unsharp Mask. One should note however, that it should be avoided on images with an ISO over 400, that are badly exposed, that have had large tonal adjustments with a “smart photo fix” feature, or that contain large flat areas of blue sky. Unsharp Mask: Because this selection provides three adjustable controls, it provides much more control over either of the Sharpen or Sharpen More options. Furthermore, it applies a selected contrast boost, at pixel level, to parts of the picture with varying lightness levels.      Radius: This Is the number of pixels around the point of contrast difference. You should start by applying a 2 pixel radius. [Too much Radius will create a whitish halo around the high-contrast sections of the image]      Strength: This is the amount of Contrast applied to the pixels selected in Radius. [Too much Strength can create a fiendish grittiness]      Clipping: This control affects the lightness of the chosen pixels. Always start with zero. [Too much Clipping causes the image to appear soft, destroying the effects of the sharpening] NOTE: If you already have a high contrast image, you can add a small amount of Clipping to soften its impact] High Pass Sharpening: This option allows for more selective sharpening of poorer images.      Radius: This Is the number of pixels around the point of contrast difference. It may have a default setting of 10. The larger the number - the more of the image that is affected and vice versa. TIP: Find an area you don't want sharpened, such as out-of-focus areas, and reduce till you see little to no effect.      Strength: This is the amount of Contrast applied to those pixels and sometimes has a default of 70. Remember: Too much Strength can create a fiendish grittiness.      Blend Mode: This selection has three options (Light | Overlay | Soft Light) that determines the Intensity of Sharpening. Each selection reduces/softens the amount of sharpening. My recommendation, practice using Unsharp Mask and avoid the simple, one click sharpening options. Hopefully this has helped you better understand your options when it comes to applying sharpening techniques to an image. Now go out there and begin practicing remembering that, “practice makes perfect”.