Negative local sharpening in the zero to –50 range can be used to fade existing sharpening. Therefore, if you apply –50 sharpness as a localized adjustment, this will disable any capture sharpening. As you apply a negative Sharpness in the –50 to –100 range, you start to apply anti-sharpening, which is kind of like a gentle lens blur effect. But you can in fact go beyond the +100/–100 limit by applying multiple passes of negative sharpness. In other words, if you add multiple adjustments with a –100 Sharpness value, you can increase the amount of blur. However, with multiple negative sharpness adjustments the effect will eventually max out and won’t become any more blurred beyond a certain point.
There are a number of examples of where a negative sharpening effect might come in handy. I sometimes use this technique to help create a shallow focus effect and therefore find it is best to apply a negative sharpness adjustment via a Graduated Filter. Another popular technique is the use of a shallow focus effect at the post-processing stage to give video footage a miniaturized feel. I have seen a number of successful examples, but one in particular that stood out was “The Sandpit” by Sam O’Hare (www.vimeo.com/9679622). Now, although, according to Sam, the original raw files were color processed in Lightroom, the after effect blurring was created using separate software. However, knowing it might just be possible to do everything all in Lightroom, I thought it might be interesting to do a test and see how well Lightroom could carry out such blurring.
1. This shows an image before applying a localized blur effect.
2. To begin with, I selected the graduated filter tool, set the Sharpness slider to -100 and Clarity to -30, and dragged from the top to the middle. I repeated this effect a few more times to achieve the cumulative blur seen here.
3. I then repeated the same thing for the bottom half of the picture, where I applied four graduated blurs to achieve a maximum blur effect.
If you are using Process 2003, you can only evaluate the noise reduction by inspecting the image at a 1:1 view or higher. If you are using Process 2010/2012, the sharpening and noise reduction can be previewed at lower viewing resolutions. However, I still recommend you use a 1:1 view in order to properly evaluate the sharpening and noise reduction, since the less than 1:1 previews can’t be relied upon as being completely accurate.