Whether you’re scanning old photos onto your computer, or downloading images from your digital camera, you will probably encounter a few blurry photos. It can be difficult to impossible to fix these problems with a scanner or camera. We have an aging Canon PowerShot digital camera which we bought around 2005. Though it still works, it often goes astray. Sometimes we take a picture that doesn’t come out quite right, but that we would like to rescue.
My husband is a Photoshop expert and we do have a subscription to Adobe Creative Cloud. But alas, the latest version Photoshop does not run on Linux, so I always use GIMP for these types of photographic repairs. Anyway, I like GIMP because it’s free. Which of course means that the updates are also free. If your distro comes with an out of date version of GIMP, I strongly recommend that you install the latest version, or use the Flatpak app for GIMP.
It’s best to never assume that one tool or another is going to do the trick for fixing blurry photos. I always try different tools until I get the right effect. The temptation for the uninitiated is to go for the sharpen tool, but generally speaking, that is not a good idea. I’ll explain why in the following sections.
Fixing Blurry Photos with the Brightness-Contrast Tool
The brightness-contrast tool in the Colors menu is one of the best tools for fixing all sorts of photographic problems. In GIMP 2.10, the brightness-contrast tool has numerous options that can help fix blurry photos by improving resolution and clarity.
For the above fuzzy photo of a dragonfly, I chose the Brightness-Contrast Tool from the Colors Menu, and set it on the Darken only – Multiply setting. This is much better than the Sharpen tool, which would add a lot of artifacts and grainy texture to the image without necessarily enhancing the detail.
Then I used the Free Select Tool from the toolbar (the icon looks like a lasso) to select the leaves in the foreground, and reduced the saturation using the Hue-Saturation tool, also in the Colors Menu. Then I used the Free Select tool to select the fern-like leaves on the left side of the image, and increased the saturation and decreased the lightness in the Hue-Saturation tool. Then I selected the dragonfly with the Free Select Tool and used the Brightness-Contrast Tool to increase both the lightness and the contrast. I used the Clone Tool from the toolbar (the icon looks like a person’s head and shoulders) to sharpen the outlines of the dragonfly and the leaves, and the Burn Tool (by selecting the Smudge Tool, then pressing SHIFT + D and selecting Burn from the tool options) to increase the contrast of the dragonfly’s head and back. Here is the result.
The level of detail you would like to achieve is entirely up to you, but you can usually make dramatic improvements with the Brightness-Contrast Tool alone.
Fixing Blurry Photos with the Curves Tool
The Curves Tool in GIMP is handy for fixing all kinds of photographic problems, but it works particularly well with blurry photographs.
For this blurry photograph of a yellow swallowtail butterfly, I first selected the outer edge of the butterfly with the Free Select Tool. Then I used the Curves Tool to improve the brightness and sharpness of the butterfly. It’s best to keep the Curves within the range of the histogram shown in the window. I adjusted each channel, red, green, and blue, down on the left, and up on the right, as shown below.
Then I clicked Select – Invert to work on the leaves in the background. I adjusted the Curves differently this time, bringing the values down on the left but not up on the right.
Then I adjusted the image using the Brightness-Contrast Tool, bringing the contrast up and the brightness down a little. Then I applied an Unsharp Mask from the Filters – Enhance Menu to just the butterfly. Here is the finished photo.
The Free Select Tool was instrumental in fixing this photo. I don’t recommend skipping this step, as the Free Select Tool is what enables us to remove the blurriness from the outer edge of the main subject of the photo. If you struggle with getting a clean line with the tool, you can select an area around the object you wish to select, then use CTRL + click to remove unwanted areas from the selection.
Fix Blurry Photos with the Levels Tool
The Levels Tool, located in the Colors Menu in GIMP, allows you to pick a white and a black input level to rebalance the color, brightness and contrast of an image.
For the image above, I chose a shiny spot on the wood rack for the white level, and a black spot on the same rack for the black level.
I then used the Free Select Tool to select only the kitten in the picture. I reapplied the levels by selecting a white and black spot on her fur, and then I applied an Unsharp Mask only on the kitten. I used the Burn Tool to enhance her facial features, and I used the Clone Tool to remove the blemish from her nose. Then I used the Mean Curvature Blur from the Filter Menu to the entire photo.
Fix Blurry Photos with the Unsharp Mask in GIMP
The Unsharp Mask is not my first choice for fixing blurry photos, but it is useful in some situations. Below is an image of a heron which turned out a little blurry.
I applied the Unsharp Mask with a radius of 3.950, an amount of 3.792, and a threshold of 0.105.
As you can see, the Unsharp Mask has left some unwanted artifacts and graininess on the image. You can leave these grainy parts in place or you can remove them using the Clone Tool or Paintbrush Tool from the toolbar.
In the above image, I have removed the most obtrusive grainy areas and applied a Mean Curvature Blur. However, there is still a “posterized” effect in some parts of the image that are hard to correct. In some images, such as nature images of trees and rocks, this might not be a problem. However, in pictures of people or shiny or smooth objects it probably will have an undesirable result.
Conclusion
There are plenty of tools in GIMP that can fix blurry photos. As in the above examples, you’ll probably want to combine them to get the optimal effect. They will help you to rescue photos that might have turned out just a touch too blurry, and that otherwise might end up on the scrap heap.
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