What the hell is this Unsharp Mask thingy?
So that new top of the line digital camera putting out soft pics? Your slides that you shot with a $1000 tripod looking like butter after you scan them. What’s the deal anyhow?
With your ever increasing attention to detail you may have noticed a while back that digital capture means softer images.
Well why is that so?
From the conversion process whether it’s scanning film in a home digital scanner or capturing in camera with digital, when the image is rendered some softness is just going to happen.
Most of us know this and that is why we have to post process our images and sharpen them up a little. For a long time, especially in the beginning we used Unsharp Mask in Photoshop to re-define our images.
This tool works good in a lot of situations, but it also enhances noise and artifacts in our images. Not to long ago Photoshop introduced Smart Sharpen and it uses a much better process when applying sharpening.
There is also the option to apply sharpening in Adobe Camera Raw.
So what’s the best course to take? If you ask ten different photographers you may get ten different answers.
So here is answer number 11.
When you start looking at the finer details of your image and begin to look for the least destructive method of sharpening, you start to rule out some of the long practiced methods.
However when we look at sharpening as a whole, different situations may call for different ways to go about things.
For example: We may want to use multi-pass sharpening for an image that will be destined for print. We would first apply a small amount of sharpening in Adobe Camera Raw. Then when the image is opened in Photoshop, we may apply a small amount to further enhance our edges. Then if this image is interpolated (made to a bigger size) we may again apply one last pass.
Another example would be for an image that was destined for the computer screen. You may only apply a one time Unsharp Mask and call it good.
The bottom line is to experiment and compare to see what results work best for you output.
I have just recently came across a method described in Martin Evening’s book, Adobe Photoshop CS3 for Photographers, that I believe works the best out of all the methods I have tried for one pass sharpening.
The process is very simple and what we do first is create a duplicate layer of our image by going into the layers panel and selecting new layer (Ctrl+J). Then in the drop down menu directly above the new layer in the layers panel you select Luminosity. Next you adjust the Opacity of the layer and bring it down to somewhere around 60%. This you can experiment with for different images to see what result works best. I usually keep it around 60%.
Then you go up to your filters menu and select Unsharp Mask and adjust your setting accordingly. For images from a digital camera I usually select an amount around 100% and for my Radius around 1.0. I usually leave my Threshold to 0 or 1.
These are just rough guides for settings, you can experiment and see what works best. I have compared this method against applying a regular Unsharp Mask, Smart Sharpen, Sharpening the lightness channel in LAB mode and Multi-Pass sharpening.
I have found that not only does it deliver less noise in the shadow areas, but it provides an easy method that I use for most all of my images.
If you are scanning slides, for better results you’ll find that your Amount and Radius numbers will need to be adjusted differently than an image taken with a digital camera.
This by no means is the only way to sharpen, but I have found that for me it has been the least destructive and most efficient.
One other neat thing (and a time saver) it to create an action for this method and then you have a one button sharpening command.
I would recommend further reading on this in Martin’s book. He goes into greater detail about more advanced and selective methods.
Again the best way to compare all the different methods out there is to try em’ out and compare side by side.