High Pass Filter
I've written before, but it bears repeating: I have no idea yet what I'm doing in Sharpening.
Oh, I think I do, and I certainly try, but really understanding it? Not sure yet. I'm trying to get it down. I'm trying to experiment, and to learn.
So, here are a couple of tactics I try when I need to do some sharpening an image:
High Pass Filter
If you look at Photoshop and the built in filters you should realize, there are quite a few options.
Before I Push The Button
Before I push the magic sharpen button, it's important to remember that sharpening should be the last thing I do to the image. In Lightroom, I make color temp, white balance and exposure corrections first, set white and black points (maybe clarity) and then export to Photoshop.
In Photoshop, I do any corrections (content aware fill, erase that stray leaf or blade of grass, etc) then I do my final cropping. When I'm happy, and only when everything else is done, then I try / attempt / play with sharpening. I good tip I picked up from many others before me, I sharpen my images at 100% view on my screen. It helps me look for problems, weird noise or color artifacts.
Native Photoshop Sharpen Filters
If you look at Photoshop and the built in filters, you should realize, there are quite a few options. The big thing to learn, is that Photoshop’s own filter, the generic Sharpen filter is bad. It applies an algorithm that you have zero control over and hits everywhere, so it probably won't do what you want it to do. Same for the Sharpen Edges and Sharpen More filters. No control, and applies to wide a swath.
Probably, the most commonly used filter in Photoshop is Unsharp Mask. When you try Unsharp Mask, you'll see it has three settings, Amount, Radius and Threshold. Amount is how much sharpening is applied to the image (Check out the image at 100% to see the effect as you move the sliders.) The Radius control determines how much around each pixel the filter is applied. The rule of Thumb is to aim for between 0.3 to 0.5. And finally, Threshold should be set to between 0 and 1. Again, check out your image at 100% to see the effect as you move the sliders.
Another Photoshop sharpen filter is Smart Sharpen, (or Adjust Sharpen in Elements) now in newer Photoshop versions. Here you have two controls, amount and radius, similar to the Unsharp Mask filter. Underneath these two, you can define what type of blur you want to remove, like Gaussian, Motion or Lens Blur. For me, I am usually trying to remove Gaussian Blur. Under the Advanced tab you can choose to apply sharpening to Highlights or Shadows.
Smart Sharpen is something I am just beginning to play with.
Sharpening, Made Easier
So, sure, you have a few options: Unsharp Mask, Smart Sharpen, and the High Pass Filter
No one method works best for every image. No method works best for every photographer. Try each one out. Try them on the same image. Try different images. Most importantly, always be open to trying new methods. You never know, you might find something new works for you.
High Pass Filter
This is another filter for getting sharp images without creating artifacts.
Check out my recent post on High Pass Filter http://www.bluefinstudios.com/blog/2014/3/tutorial---sharpening-with-high-pass-filter
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