Removing Noise with Adobe Lightroom
One of the benefits of spot metering is that you can dial in the metering to a specific area of the photograph. Sometimes, when using spot metering there are large areas of the photograph that are dark. I found this to be true with concert photography. Since the light was minimal, I needed to use a higher ISO speed and did pick up some noise in my photographs.
What is Noise?
In the film days, higher-speed film would contain large amounts of grain in the developed photograph. Rather than seeing large sections of consistent color, those sections would be grainy rather than smooth. I remember using ISO 800 film at parties and being really disappointed in how the photos came out. The whole photo just looked grainy. With advances in camera technology, noise has been reduced but is still an issue. Noise doesn’t become a problem though until much higher in the ISO range.
Let’s take a look at noise in one of the photographs from the prior post – Understanding Exposure: Spot Metering.
I found that with a higher ISO speed, this photograph picked up some noise I wanted to get rid of. Because of the large areas of black and high ISO, this photo was more likely to get noise than normal. Let’s start with the original photo:
As I walk through each example, I’d encourage you to look at each photo in full resolution to see the artifacts mentioned in the article.
Remove Color Noise
The flecks of red, green, and blue are known as color noise. Color noise often shows up most readily on dark backgrounds. We can see some noise on the subjects pants, and even less on the subject’s shirt and hands. Adobe Lightroom 5 has excellent facilities for removing noise in photographs. The first step is moving the Color slider to the right until the red, green, and blue flecks disappear. It may take a moment for Lightroom to keep up. We can see the color noise all but disappear.
The next step is to sharpen the image to make edges clearer. Sharpening adds some noise, but the tightening up of the edges makes the noise worth it. Key areas to look at are the seams in the subject’s pockets as well as the border between his hands and the back background. To sharpen, move the Amount slider to the right I’d start with a value of 70 which I also used in this photograph.
Reduce Noise Again
Now that we have sharper edges in the photograph, we can take a second pass at removing the “static” in the photograph. To do so, slide the Luminance slider to the right. Lightroom may take a moment or two to apply the effect. We lost some of the crispness from sharpening, but the benefit in noise reduction is worth it. I’d start with a value of 40.
So why not slide the slider all the way to the right? Let’s do that!
The problem with reducing noise is that it also reduces detail. The subject’s arms look too washed out. With each of these effects, only apply the amount you need. Always see if you can back off a bit and still have the desired effect.
Also consider the final output format for the photo. We are looking at this photo at full resolution. Every imperfection is apparent. Email and general web use do not need near this level of detail. Even printing 4x6in photos small imperfections won’t show up. If giving JPEG photos to a client, assume they will print at high resolution.
Do the work so you look good: in full detail.