Digital Darkroom; Sharpening Lightroom & Camera Raw

The Digital Darkroom is a series of posts aimed at beginners and those interested in Digital Photography and Editing. In previous weeks we have looked at basic adjustments, curves, editing colour with the HSL/Color panels, black and white toning, split toning and local adjustments. This week we are looking at using split toning to help create a rounded image. If you wish to check out previous posts in the series you can do here.

In digital editing, sharpening is a three step process; Capture Sharpening, Creative Sharpening and Output Sharpening. In Lightroom and Camera Raw you can do all three. This week I am looking only at Capture and Creative sharpening. In a later post I will look at exporting a picture and sharpening the picture for output then.

If you wish to watch the companion video for this post you can so here

If you would like to read a more in depth series about sharping, you can read my sharpening series here.

Sharpening

Sharpening in Lightroom and Adobe Camera Raw uses an unsharp mask  applied to the luminance of the image. Unsharp mask works by creating contrast between light and dark pixels (lighting light pixels and darkening dark ones) emphasizing edges. Although the process creates an apparent sharpness, the computer though doesn’t know if two pixels next to each other are actually an edge or digital noise, this can lead to artefacts being created where there are no edges.

The sharpening panel in Lightroom and Camera Raw have four sliders;

• Amount– the strength of the sharpening
• Radius– the size of difference between light and dark before it is considered an edge. A larger radius means the edge must be thicker before it is sharpened.
• Detail– controls the amount of sharpening on the edges of details. High setting results in small details being sharpened more where as a low detail setting will result in these being sharpened less. The issue with increasing detail is that digital noise may be inadvertently sharpened especially if you have been using a high ISO.
• Mask– allows you to isolate areas that you want sharpened and not. The higher the mask setting the more selective the areas that are being sharpened, a low setting more areas are sharpened.

With each of the settings you can preview the adjustment by holding down the alt key while you more the slider. The previews are grey scale for Amount, Radius and Detail, the Mask shows up as a black and white overlay showing edges that will be sharpened as white.

Sharpening for capture

All raw images out of camera need to be sharpened. When you apply capture sharpening you are correcting the softening of an image that occurs when the picture is taken. If you have shot Jepg the camera has already applied capture sharpening and this step is not need.

When sharpening you need to view your image as close as possible to a ratio of 1;1. You can zoom into the subject of the image and use the loupe to see a 1:1 view in the preview screen.
I generally start by deciding if the image is a high or low frequency image. A high frequency image has a lot of fine details, like landscape and architectural images. A low frequency image has less fine details and smooth areas, for example portraits.

Capture sharpening is the first level of sharpening, the goal being to make sure the image as a whole image is sharp.

With a high frequency image I set the strength at first to about 40-50, to have quite a strong adjustment. I set the radius to about 1 because I want to sharpen all the small narrow edges. I set the detail to 35 for the small details to be sharpened and leave the mask at 0. From here I can fine tune the adjustments, usually lowering the radius, adjusting the detail and of course raising the mask, but not too much as I want most of the details sharp.

With a low frequency image I start with the strength set between 20-30 and  a radius between 1.5 and 2, to make sure that it is only the fine details that are being sharpened. Detail is set low between 10-20 and the mask is usually set quite high to make sure that only the strongest details are being sharpened and everything else is left smooth. The same as with high frequency images from here I can make specific adjustments for this image.

Low Frequency

High Frequency

Let’s get creative

Creative sharpening also known as selective sharpening, is when you sharpen specific areas of an image to emphasize they are the focus of the image. In a portrait this would be the eyes and possibly the lips, in a landscape or building the area that you want to be seen as the subject or focal point.  If you are going to be doing a lot of work in Photoshop then I would do these sharpening adjustments there.

For creative sharpening in Lightroom and Camera Raw you can use any of the local adjustments mentioned in last week’s post. I am going to use the brush in this post as it is quite versatile for local adjustments.
In the local adjustment brush you can increase the sharpness by just increasing the sharpness slider. When you do this it is like adding more strength to the settings you already have applied. With my orange flower the strength was set to 52, if I add 100 to my brush wherever I paint the effect would be a sharpening amount of 152. I painted in the centre of the flower with a strength of 36 to make it pop a bit more.

How much you add is up too you but when artefacts start to appear and the area looks like there is  localized noise then you may have gone too far. It is best when using the brush to zoom into the area that you are adjusting and tweak adjustments if need be if artefacts appear.

Negative sharpening

What can be added can also be taken away, negative sharpening is exactly this. With local adjustments what you add to sharpness adds to the amount you have already applied. If you add a negative value it will minus from the amount of strength you have already applied. With my Orange flower, the capture sharpening has in a way sharpened the background, to take this back to a presharpened state I can apply a local adjustment with the negative amount.

Negative sharpening is not a blurring but more a softening and can look a bit like a lens blur. There is a point when applying negative sharpening that the softening effect will no longer be visible. With High frequency images the effect will also be more obvious than in low frequency images.

When to Sharpen

All images need some sharpening and some need a bit of creative sharpening as well. When you are sharpening you are making more prominent what you focused on in camera. You cannot make sharp something that was not sharp to begin with. Trying to sharpen a blur will create more artefacts and emphasize more that the shot was out of focus.

When sharpening especially high ISO images you need to keep an eye out for noise, the topic of next week’s Digital Darkroom.

If you have any questions or comments please use the comment box below, all are welcome as this series is designed to help people learn how to use Photoshop and Lightroom.

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