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When it comes to photography with digital SLR cameras I always recommend setting the in camera sharpening setting to zero. Doing this gives you the highest quality RAW file to work with and also gives you much more creative control once you are in Photoshop CS (PSCS). While Raw conversion programs will apply some sharpening to the image, I almost always find that I need do some additional sharpening before I print an image. Take note that it is usually best not to sharpen an image until it is ready to be printed, posted on the web or made ready for presentation in some other form. The reason for this is that most magazines and other publications request that only unsharpened images be submitted. The ultimate sharpening tools - unsharp mask and history: When it comes time to sharpen an image you can forget about the “sharpen” and “sharpen more” tools in PSCS. The tool to use is unsharp mask (USM) (Filter > Sharpen > Unsharp Mask). While somewhat tricky to get the hang of, this tool enables the ultimate in sharpening control. Before you sharpen however I would suggest saving your image, closing the file and re-opening. You’ll see why in a minute... Before sharpening I like to convert images over into LAB mode (Image > Mode > LAB) and then select the lightness channel to sharpen from the channels window. The reason I do this is that it cuts down on color artifacts. A general rule is that smaller files will require less sharpening. With a full size image out of a 6-8 megapixel camera I would suggest setting the sliders to 100-120%, 0.5-0.8 and 3 as a starting point. You can then adjust each as necessary until you have achieved a result that is pleasing to you. Do note however that over sharpened images are definitely undesirable. And always preview your images at 100 percent when sharpening. Once satisfied you can convert your image back to RGB colour.
One little trick that I often use (the reason for saving, closing and re-opening) is to sharpen the image so that the straight edges (such as a birds beak) are getting just slightly over sharpened. Then I use the history brush to “paint” over these over-sharpenned spots yielding an overall image with maximum sharpness. Selective sharpening: I stated above that I never sharpen an image before I am ready to print or display it. That is not entirely an accurate statement. In some cases I will selectively sharpen an area if I feel that it improves the image. Most of the time this involves sharpening an area around the subjects eyes. Here's how I do it:
First I zoom right in on the eye and select an area that I would like to sharpen using either the eliptical marquee or magnetic lasso tool.
Then I expand the selection (Select >Modify >Expand) and feather (Select > Feather) the selection so that the sharpened area blends in with the rest of the image.
I then convert the image to LAB mode and select the lightness channel as described above and apply the USM filter.
Finally I convert the image back to RGB and I may use the history brush on the actual surface of the eye to remove any artifacts that may have appeared. Sharpening for printing: When I sharpen an image to send to the photo lab I always sharpen it more than I would normally. The reason for this is that the printing process inherently involves some loss of sharpness. A little tip that I picked up a while ago was to view my images in PSCS at 50% when sharpening an image to send to the lab. The result is that the image gets over-sharpened just enough to balance out the softening process of the printing. Sharpening for the web: Sharpening an image for the web works the same way as described above. Just make sure that you adjust the vales of the USM filter accordingly. I usually present my images on the web as 4 x 6 inch images at 120 pixels / inch. To sharpen an image of this size try out settings in the neighborhood of 100-120%, 0.3 and 1 as a starting point. |
