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2.4 Noise Reduction and Pre-Sharpening

Pre-sharpening and noise reduction are the last steps before you convert and export your RAW image to the raster editor. It's best to be conservative with this step and use a light touch.

2.4 Noise Reduction and Pre-Sharpening

In this lesson, we'll touch on appropriate levels of pre-sharpening and noise reduction for our photo. So first, let's talk about the concept of pre-sharpening. Pre-sharpening as a common practice use to restore crispness that's was lost from the original scene back into your raw image. It's a way of neutralizing and correcting your image as oppose to adding style to it. You wanna be careful that you don't over sharpen your image at this stage. Especially because you'll most likely be sharpening areas of your image later, when you get to the stylistic phase of your workflow. So let's pre-sharpen our image. First, we're gonna make sure our image is at 100% And we can use the one-to-one button above the image. Next, let's settle into an important area of our photo. And if you want to, you can select the small arrow on the side of your left-hand panel, which removes the left panel and allows you to further focus on your image. Now let's head over to the detail pallet, and we're going to look specifically at the DXO Lens Softness. We'll select the arrow to display those settings, and these settings were automatically applied with the module that we installed upon first opening our image. The DxO Lens Softness tools are made up of three sliders. First, you have your global slider, which allows you to sharpen the overall image. And so, if you click and drag that slider to the right, your image is sharpened overall ever so slightly. And if you take it to the left your image is noticeable softened. Next you have your detail slider which allows you to bring out the details of your image. So if we increase the value of that slider, details are further accentuated. If you decrease the value of the slider, details are softened. On the bottom you have your Bokeh slider, which prevents artifacts from appearing in the soft, blurred areas of your image. And so we're going to increase the details of our image. Just to restore the sharpness of the original scene. And we'll take it up to a value of 93, and then we're going to use our compare button to look at where we started before, verses where we are now. And so you can see the image is sharpened ever so slightly. Now in the case that you're processing a photo that does not yet match up with one of their pre-made modules, you can use the unsharp mask tool in order to sharpen your image. Lets head down to the unsharp mask option and look at those settings. The unsharp mask option has four sliders. First, you have your intensity slider, which allows you to adjust the sharpness of your entire image. You have your radius slider, which allows you to further adjust the amount of sharpness applied to the image. You have your threshold slider, which allows you to sharpen the contours in your image while leaving the flat surfaces alone. And then you have your offset slider, which applies sharpening to the edges of your image. We'll leave the unsharp mask options alone, and therefore the button turned off, but it's a good option to be familiar with. And we'll go ahead and close the DxO Lens Softness settings. Now, let's talk about image noise. Image noise occurs when seemingly random pixels become visible in your image. It can give your photo a grainy feel. And often appears in areas of solid blocks of color. This is known as luminance noise. Image noise can also have random flecks of color in it, which is known as chroma noise. When excessive and unintentional, image noise in general can be distracting and potential detract from the content of your photos. There are several causes of noise, including using ISO settings that are simply too high, or shooting in low light. Sometimes noise is caused by using a slow shutter speed, or even when your image sensor heats up. Also, you may run into noise if you're using an inexpensive camera. As far as trying to prevent noise, try to shoot with the lowest possible ISO setting without compromising the quality of your image. Shooting in raw helps as well because it doesn't compress your image, allowing you to retrieve details later. And just a quick note, we don't want to remove all noise from our photo, we just wanna remove it to the point that it's not detracting from the content and aesthetic focus of our image. If you were to remove all of the noise in a photo, it would look to begin to look unrealistic. In this base processing phase that we're going through right now, that is not our intention. We just want to bring our photo to a neutral level. Let's take a look at the noise reduction options available to us. Let's head over to the noise reduction tools and select the arrow to display the options. You have two main options, high quality and prime. The high quality setting uses an algorithm that's quick and produces a high quality result. And the luminance slider beneath it reduces the fine grain inner image. And so you can see that our image already has noise reduction applied to it because of the module that we installed. It's currently on a setting of 40. If we were to increase that, noise is further reduced in our image. And if we were to decrease the luminance setting, then it will allow more fine grain to appear in our image. We'll leave it on the setting of 40. And next, we have the Prime setting, which is one of the DxO's most advanced features. And it works effectively on images with extremely high ISO settings. It will only show you a preview in the small preview window below, opposed to the entire image. And you'll notice that when we select the prime option and we get the crossed out eye icon, letting us know that it can only be viewed in the magnifying window within this palette. And again, you have your luminance slider to remove the fine grain in your image. For this image because it does not have a lot of noise issues, we'll leave it on the high quality setting, and again the default setting of 40 for the luminance slider. And let's take a look at our image. We'll zoom to fit. And this is what we started with and this is where we're at right now. That brings us to the end of this lesson. In this lesson, we explored pre-sharpening and noise reduction for our image. This also brings us to the end of this chapter. In this chapter, we took various steps to neutralize our photo. In our next chapter, we're going to export our photo out of DxO, thus ending the raw processing stage. We will open up or resulting raster image in Pixelmator in order to add a bit of style to our photo.

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