I’ve been exploring more of Digikam’s possibilities of late and I came across the ‘Local Contrast’ tool. I had never heard of this before, and a quick search led me to understand that it functions similarly to the LDR Tonemapping utility. Here’s the write-up from Scribbles and Snaps:
digiKam offers several features that can improve photos containing under- or overexposed areas. For example, the Exposure Blending tool lets you merge multiple shots with different exposures into one perfectly exposed photo. But what if you have just a single image? In this case, you might want to give the Local Contrastfeature a try. It’s based on the LDR Tonemapping utility which is designed to improve the dynamic range of the photo by reducing its global contrast and increasing the local contrast. It does so by generating a desaturated and blurred version of the photo. It then combines the RGB channels of the original photo with the desaturated blurred image using either the Linear or Power function. Sounds complicated? Don’t worry, the Local Contrast tool is rather straightforward to use, so you don’t have to understand all its intricacies in order to achieve pleasing results.
Apparently it is good for bringing out detail in the shadows or highlights areas that have been over or under exposed.
I had just taken a photo of a local farmhouse which I was going to use for an HDR image. So I decided to give the Local Contrast Tool a try beforehand.
Here’s the original image:
As you can see, the main portion of the image is underexposed. This would originally have been the underexposed image in a series of three exposures for an HDR image. After applying the Local Contrast Tool using just the standard settings with the first three stages (tonemapping operations) activated, I ended up with this image:
I was quite surprise at the result. This is almost HDR-like from a single image. Somehow, the image is very smooth (soft) and unsharp, but this was just a trial. I will have to look into the setting further to find out the ideal settings.
A second image I used was this one:
After applying the above settings again, I ended up with this one:
These are sized down images pulled from my Picasa album, so the originals look better than this. Still, I think this is quite an interesting tool. I can see some uses here with slightly underexposed areas.
Do you have any experience with this tool? How do you use it in your workflow? Can you recommend any settings?
Would love to hear from you.
Click that shutter!