The secrets behind Marc’s Lab Sharpening Technique

Nearly every photo I’ve post online has the Lab Sharpening Technique applied.

Digital photos tend to shoot a little on the soft side even with on board sharpening which many digital cameras have today. You’ve seen photo online and might have wondered: “How did they get the details so fine?”.

This is a basic must know PhotoShop technique to sharpen up the fine details in your photos. Most budding photographer’s will use PhotoShop’s Unsharp Mask (I know, why do they call it Unsharp when it sharpens). That’s great but it can cause an unwanted halo effect on fine lines and details.

Here’s an example of the Lab Sharpening Technique. That little extra edge for fine details.

Lab Sharpening Technique Sample by Marc Mantha

Here’s the full sized sharpened web photo.

Why the Lab Sharpening Technique?

Using PhotoShop, this technique applies the sharpening to the Lightness Channel in Lab Color Mode instead of all the image channels. It’s doing the same as the more commonly used Unsharp Mask, only better.  This works great for adding a nice punch to the details for web posted photos or print. Be aware that Lab Sharpening for print and web are not executed in the same way. I’ll show you more in Part II coming soon.

Talk to me

If this sounds like an alien language, don’t worry. I’ll lay it all out for you. I want you to be successful.

This also applies to most any version of Adobe PhotoShop too. Although the video tutorial was produced using a Mac, the process is exactly the same with the Windows version. It just looks a little different.

I have a web-cast demonstration for you lower down.

PhotoShop Smart Sharpen Screen ShotPart I – Sharpening a web optimized photo:

  • Change the color  mode from RGB to LAB. From the file menu select Image / Mode / Lab.
  • In the Layers Panel (aka Layers Palette) click on the Channels Tab. If not visible, from the file menu at the top, select Windows / Channel and it will appear to the left of your screen desktop.
  • In the Channel tab are four Channels as follows: Lab, Lightness, a, b. Click on the Lightness channel to make it active. Your image will turn to black and white.
  • Next, from the file menu at the top, select Filter > Sharpen > Smart Sharpen and the dialog box pops open (shown right). The settings for Amount tends to be under 100% with a radius of about 0.5 when sharpening web sized photos.
    • Optional, you can then add a small amount of Smart Sharpening to the overall image by clicking on the Lab channel as demonstrated in the web-cast.

The overall advantage of the Smart Sharpening the Lab Lightness channel is that it better avoids halos around fine details more common to using the Unsharp Mask.

NOTE: Once you have finished sharpening, you can’t save as a JPEG while in Lab Color mode. Simply go to the File Menu at the top, select Image > Mode > RGB. Now save as a JPEG if desired.


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