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Gallery
25 January 2012
Sharpen details for flawless images
Heading: Photoshop.
George Cairns shows you how to produce portraits with punch, by maximising image detail and minimising unsightly artefacts.
Even the best photographers can find it a challenge to capture a perfectly focused photograph, especially when shooting with a camera set to a wide aperture. The resulting shallow depth of field can make it difficult to get all of the key areas in focus.
Some cameras use a low – pass filter to help reduce the false moire – pattern colours produced by complex textures. But this in – camera filter tends to blur the image, producing a soft – focus result. Its also hard to tell if a shot is actually sharp when you view it on the cameras LCD screen.
Theres no substitute for getting a shot sharp in – camera, but Photoshop Elements does have a range of commands designed to help you reduce blur and reveal more of the images delicate details. The sharpening commands work by increasing the contrast around the edges of features such as eyelashes and hairs, giving them a more defined appearance.
ADDING ARTEFACTS
The downside to sharpening is that it can also add unsightly artefacts. For example, if you increase the spread of the contrast change it can add ugly white or dark halos around objects. Sharpening can also emphasise things such as the picture noise produced by a high ISO setting.
Its all a case of getting the balance right. Here, well show you some tips and techniques you can use to tease out extra detail from a soft – focus shot while keeping ugly artefacts at bay.
Duplicate your image
Open sharpening_before.jpg. If the Layers palette
isnt already visible, choose WindowLayers to open it Drag the Background layers thumbnail onto the Create a New Layer icon at the bottom of the Layers palette to duplicate it. By sharpening the copy you can compare it to the softer start image as you go.
Zoom in on key areas
To see the how sharp the shot really is, grab the Zoom tool from the Tools palette. Tick the 1:1 button in the options bar to see the photos actual pixels. Hold down the spacebar to activate the Hand tool and drag the image to view the eyes. Delicate details such as the eyelashes look a little soft.
Tidy up blemishes
If you sharpen the image now, youll exaggerate the smudges of make – up under the eyes. To remove them, grab the Spot Healing Brush from the Tools palette. Choose a soft round tip from the Brush Preset picker with a Size of 35 pixels. Tick the Content – Aware option. Click on the smudges to remove them.
Recognise artefacts
Go to EnhanceUnsharp Mask. Increase Amount up to 500% and Radius to 10 to create typical sharpening artefacts. The shadows are clipped and lack detail, while highlights are blown out White halos cling to the contrasting black eye shadows, and even picture noise and freckles have been exaggerated.
Remove haloes
Pop Radius down to 2.0. This stops the edge contrast change from spreading too far, which helps to avoid halo artefacts. Reduce the Amount to 143% to make a less drastic contrast change. Tick the Preview box to compare the sharpened shot with the original version.
Increase Threshold
When sharpening, you can end up exaggerating image noise and low – contrast blemishes such as freckles. By increasing the Threshold sliders value you can get the Unsharp Mask to leave the low – contrast areas alone, while still sharpening darker details such as eyelashes.
Adjust Sharpness
Click the Unsharp Masks Cancel button. Lef s try EnhanceAdjust Sharpness instead. This newer command gives you a larger preview area and a few extra controls. Set Amount to 130% and Radius to 20. Hold the mouse button down on the preview window and then let go to see a before and after version.
Explore extra options
For a more subtle sharpening effect, set the Remove drop – down menu to Lens Blur. This creates a less harsh contrast change, which helps stop darker details becoming clipped. The More Refined box sounds good, but it tends to reveal more unwanted picture noise. Leave it unticked.
Learn the lingo
ISO
To make your digital camera more sensitive to available light, you can use a higher ISO setting such as 800. However, this faster speed can add more digital noise to your image, which is then in danger of being exaggerated by the post – production sharpening process. By using a wider aperture and a slower shutter speed you will be able to shoot with a lower ISO value.
Learn the lingo
Unsharp Mask
Photoshops Unsharp Mask command has a strange name, as it seems to offer a way to blur a shot rather than sharpen it. The command actually derives its name from a traditional darkroom technique that involved sharpening a negative by combining it with a blurred positive version of the image. The newer Adjust Sharpness command has a more sensible name.
Stop motion blur
When shooting a moving subject you risk capturing motion blur. The Motion Blur drop – down menu is designed to help you counteract this problem using an angle slider, but this is a fairly ineffectual tool. Its better to shoot with a faster shutter speed to avoid motion blur, and then brighten up the under – exposed shot
Compare before and after
Leave the Remove option set to Lens Blur and click OK. Click the Background copy layers eye icon on and off to show the sharpened layer and compare it with the original Badgnound image. The eyes now look much sharper, but you can also see unwanted noise in the soft – focus areas of the girls hat
Add a layer mask
The top of the hat is well out of focus, due to a shallow depth of f eld, so you cant sharpen it. Youll need to limit the sharpening to key features such as her eyes, nose and mouth. This will keep sharpening artefacts to a minimum. Click the Add Layer Mask icon at the bottom of the Layers palette.
Sharpen key features
Select the Background copy layers mask. Hit ctrl+l to turn it black and hide the sharpened layer, revealing the blurred original. Grab the Brush tool and select a soft300 – pixel tip. Click the mask Set the Foreground colour to white, then spray to sharpen the key features while leaving the blurred hat unsharpened.
Enhance your indoor shots
Depth of field
Selective sharpening isnt just great for portraits; its also perfect for enhancing still – life shots like those in our feature on page 36. This technique is particularly useful for images that have shallow depth of field.
Sharpen detail
You can use this sharpening technique to enhance the detail in the sharply focused areas, such as the centre of this Gerbera, ma king them really stand out in the final image.
Minimise noise
By using a layer mask to only sharpen the detail you will minimise the amount of noise and sharpening artefacts that would otherwise be visible in the out – of – focus areas.
Avoid haloes
Its easy for sharpening to produce haloes around out – of – focus areas such as the green stalk against the blue background. Again, usingthe layer mask minimises the chance of this occurring.
Did you know?
Auto Sharpen
Are you in a rush? Well Photoshop Elements has an Auto Sharpen command in its Enhance menu. This gently sharpens the shot, but it doesnt give you any control over the sharpening amount. You can try Auto Sharpen on a problem image and then repeat the command a few times to sharpen the photo in increments.
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