Sharpening your images shows more detail and enhances focus in your image. Due to failures in digital technology, which tend to introduce “softness” into your images, it’s usually necessary to apply some sharpening.
I’m going to show you a method of sharpening, called the “Unsharp Mask” method, that’s less destructive (with much better results) than the generic Photoshop sharpening tools. Give this method a try – you’ll be amazed, ands it’s much harder to “over-sharpen”.
By the way, don’t let the term “Unsharp Mask” deceive you – it really does sharpen your image! The term’s a carryover from the analog/film days.
When to Use:
Sharpening is one of the last things that you’ll do to an image.
Note: You should never sharpen your Master File (See my last column on “Master Files”).
The amount of sharpening that’s necessary for a 16×20 is more than it would be for an 8×10. If you sharpen your Master File for a 16×20, your 8×10 will be over-sharpened. It’s best to sharpen a duplicate of your Master File for the intended output size.
This method involves creating a Background Copy. You can then selectively sharpen just part of your image by creating a Layer Mask on the Background Copy and “painting out” those areas you don’t want to sharpen (we’ll cover this in future columns).
© 2011 John Watts. All Rights Reserved.
How It Works:
Step 1:Create a New Background Layer. To create a Background Copy, simply drag the Background Layer to the “New Layer” button (just to the left of the “Trash” button at the bottom).
Step 2: Change the Blending Mode. Make sure that your Background Copy is active (highlighted) and then change the Blending Mode to “Luminosity”.
Step 3: Go to “Filter” menu –> “Sharpen” –> “Unsharp Mask…”This brings up the Unsharp Mask Dialog Box.
Step 4: Apply the proper amount of “Unsharp Masking” (more on this in a minute). Click “OK”.
Some Pointers to Get Started:
Suggested starting points in the Unsharp Mask Dialog Box are:
Amount = 50 to 200
Radius = .9 to 1.2
Threshold = 1 to 3
Typically, I leave the Radius at 1.0, Threshold at 3, and I’ll increase the Amount until it looks over-sharpened, and back off a bit.
How much is too much? Mostly you’ll have to rely on a bit of trial and error at first, but the trick is to keep things looking natural and not too intense. You’ll gain more experience at this as time goes on.
By the way, if your image isn’t fairly sharp to begin with, I wouldn’t expect Photoshop to correct it completely. When it comes to sharpening, it’s not a miracle program.
© 2011 John Watts. All Rights Reserved.
Previewing in the Unsharp Mask Dialog Box:
1. You can “preview” your sharpening in the Preview Window in the Unsharp Mask Dialogue Box by holding your cursor over it (the cursor changes to a “hand”), then pressing your left mouse button – pressing it and holding it down is the “before” view, releasing the mouse button is the “after” view.
2. You can also put the cursor in the Preview Window, press and hold down the “Space” bar on your keyboard, press and hold down your left mouse button, and drag the view of the preview pane to a more desirable location.
3. With the Unsharp Mask Dialogue Box open, you can put the mouse cursor in your actual image (a small square “box” will show up as your pointer), place it over an area that you’d like to see in the Preview Window, and left-click: Voila! That area shows up in the Preview Window.
How to View Your Image for Proper Sharpening:
I normally judge the effects of my sharpening with my image at 25% magnification – this is “actual size” (or close to it) on my monitor if the image resolution is 300 PPI.
I’ll also set the Preview Window in the Unsharp Mask Dialogue Box at 50% (default is 100% – press the “minus’ symbol to reduce).
Between the two views /magnifications, I get a real good feel for how the final image is going to look once sharpening is applied.
Use the “Preview” check box to judge the effects of the sharpening in your image (This does not “preview” in the Preview pane).
Until the next time, have fun and stay well!
by John Watts, Watts Digital Imaging