I was outside a few evenings ago experimenting with my camera when I wandered into the garden at the front of our house. The garden is quite diverse, so I decided to stay for a while to take a few photos. I’m pretty happy with what I got and honestly, I wasn’t going for anything spectacular. I think my primary goal was to take some photos in RAW mode for this website. Unbeknownst to me that evening, the photos I took would come in very handy. I’ve already used them on a number of occasions for all sorts of things.
There wasn’t a lot of light when I was taking the photos, so the ISO value is higher than I would normally allow. Since I wasn’t paying too much attention, the resulting photographs have a bit of noise in them. I was just sitting at my desk editing a few of them when I realized that I should actually be posting the simple process I follow. It’s really only a push of one or two sliders. What’s important about following the steps of removing or reducing noise in photography is understanding what each slider can accomplish. I think I’ve written about this in the past, but I’ll repeat it here; instead of heading into an editing application with no goal and pushing sliders around until the image looks good, you should be initially working on the photo with a goal in mind and you should know which sliders to push beforehand. This helps tremendously with efficiency later on. So that’s what I’d like to discuss below in regards to a mere three sliders.
In today’s post, I’m going to talk about the Luminance, Luminance Detail and Luminance Contrast sliders under the Noise Reduction heading in Adobe Camera Raw. Each of these sliders has its own function and each can either help or harm the output of a photo. Down below, I’ll explain what each slider does in an effort to help you go about editing your own photos with purpose, as opposed to the guessing that I mentioned above.
Today’s Demo Photo
This is the image I’ll be using for this post. I think these are some sort of flower seeds pods.
An Up-Close Look
While the photo I’m using today looks fairly decent on the surface, let’s take a closer look at it. To do so, I’ll open the image in Adobe Camera Raw and I’ll double-click on the Zoom Tool in the upper left corner.
What this tool does, if double-clicked on, is zoom the image until it reaches 100%. This certainly saves a lot of time over repetitively using the keyboard shortcut of Ctrl++ to enlarge the photo.
Anyway, now let’s take a look at some noise.
I think you can clearly see the noise in the image now. Also, just in case you’re wondering, the camera settings for this photo are aperture of f/5, shutter speed of 1/30 and an ISO of 6400. The ISO value is what got me into this mess. The sun was almost down too, so that’s what caused that high value.
The Luminance Noise Reduction Sliders
As I mentioned up above, I’m only going to focus today’s post on three sliders. What’s important here is that you know what these sliders do, so I’ll try to explain as best I can below.
Luminance: This type of noise deals directly with the brightness of any given pixel contained in a photograph. This noise most often stems from higher ISO values, meaning, the sensitivity of the camera’s sensor is amplified in an effort to capture as much light in the scene as possible. Due to this amplification, noise appears randomly throughout the image and pixels that should be one brightness value are either too light or too dark. The Luminance slider in the Detail panel of Adobe Camera Raw uses an algorithm to compare certain pixels with surrounding pixels and modifies the brightness level of any outliers. Pushing this slider to the right can reduce this type of noise in an image, but it comes at a price. Noise can be reduced to such a degree that the image can appear as something akin to a cartoon or a painting of some sort.
Luminance Detail: This slider can be considered a threshold slider in that it essentially stops the Luminance slider from reducing noise past a certain point. If you were to keep this slider all the way to the left, the Luminance slider would continue to flatten the image more and more as it’s pushed to the right. If you were to push this slider all the way to the right, the Luminance slider would have much less of an effect as it’s pushed to the right.
Luminance Contrast: This slider attempts to control and maintain contrast in an image. As the Luminance slider is pushed to the right and noise is removed, so is contrast. By pushing this slider to the right, Camera Raw tries to maintain that contrast, but if pushed too far, blotches can appear in the image.
Reducing Noise in This Image
From reading the above slider descriptions, you may have correctly deduced that the critical slider among the three is the Luminance slider. That’s the one doing all the heavy lifting. The other two are sort of correction sliders that keep the first one from misbehaving.
I’ll go ahead and try to reduce the noise in the image I’m working on today. To do this, I’ll move into the Detail panel in Camera Raw.
Once there, I’ll push the Luminance slider to the right some. As I do this, I’ll notice that the Luminance Detail slider immediately jumps to a value of 50. That’s fine. I’ll keep it there. Now, I’ll give you a little piece of information that I’ve discovered through the years. In general, a Luminance slider value between 35 and 50 gives good results. That’s with a Luminance Detail value of 50 and a Luminance Contrast value of . I rarely use that last slider. So in today’s case, after some trial and error, I’ll set these three values:
Luminance Detail: 50
Luminance Contrast: 0
And just from that, I’ve cleaned up the image pretty well. In this next image, the after version is to the left and the before is to the right.
I’ll leave it at that, since I’m happy with the results. It really shouldn’t be any more complicated than this. The process is simple as long as what the sliders do is understood.
Here’s the final image. I know the difference is barely discernible from the one above, but it’s there.
I hope I clearly explained how the Luminance noise reduction sliders inside of Adobe Camera Raw work as well as demonstrated what they can do when it comes to removing grain from a photo that’s been taken with a digital camera. If you have any questions regarding this post, please leave them for me in the comment section below. Thanks for reading!