Sharpen an Image In Lab Mode
Last week I made a brief introduction to Lab Mode in Photoshop, showing you around the interface. I talked about how Lab mode is made up of different channels, such as the lightness channel and the a and b channels. It turns out that Lab mode is great for sharpening images. The reason is that the lightness channel is separate from the a and b channels. No color information is found in the lightness channel, so if you sharpen it, you won’t be affecting the color information of the image itself. this is great, because you sharpen the image without creating artifacts and color distortions. In the video below, I will show you how to sharpen an image in Lab mode with Photoshop.
If you select the lightness channel and perform sharpening filters to it, you can sharpen your image with more control and precision. In the video, I used the Unsharp Mask Filter to sharpen the image. The Unsharp Mask window gives you three settings, Amount, Radius, and Threshold. Keep in mind that setting Amount higher, and Radius higher, each give you more sharpening. If you lower Amount and lower Radius each give you less sharpening.
Threshold works just the opposite way: the lower the Threshold the more sharpening, and the higher the Threshold the less sharpening. You are essentially raising the point, or the threshold at which sharpening of the image occurs.
It’s good to keep in mind that subtlety is best. You only want to sharpen an image slightly. You don’t want to over-sharpen an image, because it will look terrible. The key here is subtlety. The idea of less is more really applies here. You can really produce some amazing effects with sharpening in Lab mode. If you have any questions abut Lab mode, be sure to leave them in the comments section below.