There are some standard enhancements that I apply to my photos consistently: auto-levels, increase saturation, increase sharpness, etc. I’d also read that Flickr sharpens uploads (at least, the resized ones) so that they look better.
So last week, I took 100 of my photos and created 4 versions of each image:
- The base image itself (example)
- A sharpened version (example). I used a sharpening factor of 200%
- A saturated version (example). I used a saturation factor of 125%
- An auto-levelled version (example)
I created a test asking people to compare these. The differences between these are not always noticeable when placed side-by-side, so the test flashed two images at the same place.
After about 800 ratings, here are the results. (Or, see the raw data.)
Sharpening clearly helps. 86% of the sharpened images were marked as better than the base images. Only 2 images (base/sharp, base/sharp) received a consistent feedback that the sharpened images were worse. (I have my doubts about those two as well.) On the whole, it seems fairly clear that sharpening helps.
Saturation and levels were roughly equal, and somewhat unclear. 69% of the saturated images and 68% of auto-levelled images were marked as better than the base images. And almost an equal number of images (52%) showed saturation as being better than the auto-levelled version. For a majority of images (60%), there’s a divided opinion on whether saturation was better than levelling or the other way around.
On the whole, sharpening is a clear win. When in doubt, sharpen images.
For saturation and levelling, there certainly appears to be potential. 2 in 3 images are improved by either of these techniques. But it isn’t entirely obvious which (or both) to apply.
Is there someone out there with some image processing experience to shed light on this?