iPhoto Adjustments - Sharpness & Reduce Noise
This article is the last part of a series where I have covered the image adjustment features of iPhoto. Many users do not make full use of the adjustments offered by iPhoto. With iPhoto 08, Apple has introduced image adjustments that were usually only previously found in professional image editing applications.
Sharpness & Reduce Noise
The Sharpness & Reduce Noise tools allow you to adjust the edge and noise definition of an image.
Sharpness - Increasing the sharpness above the default increased the edge definition, giving the image a more crisp appearance.
Reduce Noise - Increasing the reduce noise above the default removes the peaks and troughs from the image textures, smoothing out the image.
For most image editing requirements, these adjustments should provide you with a very complete set of color adjustment tools. It should be noted that these tools operate on the whole photo. I have been in situations where I only wish to adjust a part of the image. In these cases, a more advanced image editing tool, such as Apple Aperture or Adobe Lightroom/Photoshop is required.
To display the image adjustments HUD (Head’s Up Display) in iPhoto, either of the following will work.
- Select a photo in the browser and click the ‘Edit’ button in the toolbar at the bottom, or
- Double click a photo in the browser and then select the ‘Edit’ button in the toolbar at the bottom
To demonstrate the effects that the Sharpness & Reduce Noise adjustments have on a photo, we will be using the following photo of the Sydney Opera House with a couple of passing Sydney Ferries. The image Adjustment HUD is shown to the right. Adjustments can be made in either windowed or full-screen mode.
Clicking on the following images will load a larger version in a new window, making it easier to see the effects of the various adjustments.
Sydney Opera House and Ferries - click for larger image
The Sharpness & Reduce Noise adjustments also change the tone curve displayed, similar to the adjustments detailed in the other articles in this series, Levels, Exposure & Contrast, Highlights & Shadows and Saturation, Temperature & Tint.
Each color is represented in a value between 0 and 255, and are represented on the graphs scale as between 1 and 100%.
Sharpness Adjustment
The Sharpness values can be adjusted between 0 and 1, with 0 being the default initial value.
Increasing the sharpness slider makes the image edges more defined. In the example image below, I have increased the slide to its maximum value (1). In practice, smaller adjustments will be made; however, we are showing the most extreme level of sharpening and helping to understand how iPhoto sharpens an image.
Sharpened image - click for larger image
As it is hard to see the differences that the Sharpness adjustments make to the photo details, I have included a close-up of one of the ferries. The original image is shown first.
Before Sharpness adjustment - click for larger image
After Sharpness adjustment - click for larger image
As can be seen from the close-up, the edges on the ferry are more defined and gives the image a more crisp appearance. However, with a too high a sharpness setting (I have used the maximum setting to show the effect), the image can look too crisp and not as pleasing.
Reduce Noise Adjustment
The Reduce Noise values can be adjusted between 0 and 100, with 0 being the default initial value.
Increasing the reduce noise slider removes the peaks and troughs from the image textures, smoothing out the image. In the example image below, I have increased the slide to its maximum value (100). In practice, smaller adjustments will be made; however, we are showing the most extreme level of noise reduction and helping to understand how iPhoto reduces noise from an image.
Reduced noise image - click for larger image
As it is hard to see the differences that the Reduce Noise adjustments make to the photo details, I have included a close-up of one of the ferries. The original image is shown first.
Before Reduce Noise adjustment - click for larger image
After Reduce Noise adjustment - click for larger image
As can be seen from the close-up, a lot of the detail from the sea and ferry (especially on the green hull) have been removed by the smoothing. Whilst the image still looks okay, you have removed detail from the image. The algorithm used by iPhoto to reduce the noise cannot fully differentiate between noise and actual image detail. Therefore care must be taken when increasing the slide, as too high a value will loose valuable detail.
Summary
Adjusting the Sharpness & Reduce Noise of an image can have dramatic effects on the overall image. Be careful to only make subtle adjustments at a time. I found the following tip when researching my iPhoto Adjustment articles.
When you are adjusting an image using the Adjust HUD, if you press the Shift key, iPhoto will display the original image before the adjustments were made. This is a really quick way of previewing your changes and seeing what changes they have made to the original photo.
As with all adjustments in iPhoto, it is possible to reset the changes if you over adjust an image. If the ‘Edit’ -> ‘Undo’ option will not undo all of the changes, you can revert the image to its original using the ‘Photos’ -> ‘Revert to Original’ option. When using RAW images, the ‘Photos’ -> ‘Reprocess RAW’ option should be used.
Sharpness & Reduce Noise can be a powerful and effective way of making adjustments to your photos.
Tags: iPhoto, Photo Adjustment
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