Monday, May 28, 2007

All Week: Digital Photography Tips and Tricks and Your Software

Tips for Sharpening

by Julie Ann Shahin, Founder

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Results are subtle

Did you know that most digital images need to be sharpened THREE times? Not every time, but most times a photo needs to be sharpened not once, but three times according to Ken Milburn, Author of Digital Photography: Expert Tips.

He recommends skipping your camera's feature to sharpen the photo -your computer has much more powerful ways of sharpening. Here's why you need to sharpen your images more than once:
1) The first time you sharpen, you do it because it is in the nature of most image sensors and of such things as dust-protecting and low-pass filters, which are built into most digital cameras (most especially those meant for pros and prosumers).

I'll explain the three stages of sharpening that are almost always necessary. I call them rescue, effect, and output.

Sharpening Round 1
On the Layer palette select your Background Layer and right click. Select Duplicate Layer.
  1. Do use Adjustment layers to do the various gamma adjustments (Auto, Levels, Curves).
  2. Do overall color balance adjustments (gray card, color balance).
  3. Do any color effects you're likely to want to use with a Hue Saturation Adjustment layer.
  4. Remove any image noise. I highly recommend using Nik Dfine, but if you can't afford it, you can download some effective noise removal Actions from Adobe Studio.
  5. Do basic retouching.
  6. Do basic sharpening.
Basic (non-destructive or high pass) sharpening tips:
On the Layer palette select your Background Layer and right click. Select Duplicate Layer.
  • With this new layer highlighted select Filter / Other / High Pass. Set the Radius to 10 and click OK.
  • Zoom into your image to Actual Pixels level so you can better see what you're going to do next.
  • Go back to the Layer Palette and select Hard Light from the left drop down.
  • Now go to the Opacity Slider and select a level of sharpening that seems best to you. Usually something between 20% and 70% will be best.

Sharpening Round 2

Apply free midtone sharpening action

For round 2, I applied Mid-Tone Sharpening. Download the free action

Sharpening Round 3
Sharpen your image to print it (output sharpening)

The resolution of your output device (whether it be offset press, inkjet printer, or the Web) is likely to be quite different from what you've been seeing on screen. That does not mean that you should have done any sharpening that you've done up until now any differently. What it does mean is that if you want the image you are going to finally present to look as detailed as possible, you are going to have to duplicate the image you have created so far and sharpen it just one more time especially for the device you are going to use to present that image. It is a very good idea to rename these images so that version contains the name and resolution of the output device and to then save those images in a directory or CD that is just for images meant to be printed.

There are two ways to accurately sharpen for printed output: experimentally or with Nik Sharpener Pro. To do it experimentally, use the Photoshop Unsharp Mask filter on several sections of the image -- each with different sharpness settings. Use a text layer to annotate the setting for each section. You can then output this "test" print. Use the USM settings that are closest to the best results. If you want to be really accurate, create another grid with settings that are closest to the best results. If you're really organized, write down the best settings for each different size of image that you're likely to produce from a given original file size.

If the above sounds like way too much work, and you figure your time is worth between $79.95 and $329.95, get one of the three versions of nik Sharpener Pro that is best suited to the type of printing you do. This program takes into account both the size of the image being sharpened and the resolution of the image to be output, and then automatically does the sharpening that will produce the best possible result. Source:

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