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July 19, 2007
[ GETTING RID OF THE NOISE ]
Last week we considered the nature and causes of image noise – this week we look at some ways of getting rid of it.
Let’s take the most annoying example of picture noise. You have taken a terrific landscape picture of the fabled hills of Tuscany, following the two thirds rule of composition. In this case two thirds sky and one third foreground. And the sky is a rich blue, full of fluffy clouds.
The sky is a rich blue because it is slightly underexposed, one of the conditions guaranteed to produce picture noise even in the best cameras. Instead of being a smooth blue it is mottled with what looks like film grain. Is it possible to be rid of the mottling?
When it comes to technology we know that every problem has a solution because that’s how clever people spot a business opening. It comes as no surprise that there are a number of computer software solutions to the noise problem.
Photo editing programs like PaintShop Pro and Photoshop, as well as RAW converters like Adobe Lightroom, Adobe Camera RAW and Bibble have noise reduction functions built in. Bibble Pro (U$130) uses the Noise Ninja engine for noise reduction.
Noise Ninja (U$35) is an impressive application that gives the user a great measure of control over the way in which the noise is removed. The challenge in the process is to get rid of the objectionable grain without at the same time simply smoothing away all the fine detail. In reality it is not possible to both despeckle and keep detail, but the best of these tools give the user choices in balancing one against the other. Noise Ninja is the standard against which other programs must be measured because it is the most comprehensive, stand alone, single purpose application for the job.
The “Remove Digital Camera Noise” operation in PaintShop Pro Photo XI shows side by side preview images of the original picture alongside the treated image and the preview is interactive. As the smoothing and sharpening controls change the preview image changes to show the effect. This works well because it gives an instant assessment of the trade-off between noise elimination and preserved detail. The only drawback with the PaintShop Pro function is that it is unbelievably slow in its processing, even on a fast computer.
The Adobe approach to noise reduction in Lightroom, Camera RAW and Photoshop is conservative, staying on the side of preserved detail at the expense of noise reduction. This is a purist approach that will appeal to those prepared to live with a degree of graininess.
Of all the noise reduction software we tried we were most impressed with Noiseware . In its most elaborate form (U$50) it comes as a Photoshop plug-in, but here’s the truly wonderful news, there is a Noiseware Community Edition which is free. It’s stand alone and not a plug-in, so it’s not as convenient as the integrated version, but it does the job, is really intuitive and easy to use and costs nothing. The drop-down Settings menu makes the job easy – just choose Landscape or Portrait or select the degree of noise and click on the Go button and the processing is done in a nonce. This little application makes all the others look under-nourished and over-priced.
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Posted by terry at July 19, 2007 07:08 AM
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Comments
I have been using the Noiseware Community Edition for over 12 months and I think it's a great program. Noise isn't too much of an issue with D50's but when I do need some touching up the Noiseware product does the job better then anything else IMO.
Posted by: RichardR at July 20, 2007 08:22 AM