Light Mode InFFFFFFlation

Summary

Back in the day, light mode wasn’t called “light mode”. It was just the way that computers were, we didn’t really think about turning everything light or dark. Sure, some applications were often dark (photo editors, IDEs, terminals) but everything else was light, and that was fine. What we didn’t notice is that light mode has been slowly getting lighter, and I’ve got a graph to prove it. I did what any normal person would do, I downloaded the same (or similar) screenshots from the MacOS Screenshot Library on 512 Pixels. This project would have been much more difficult without a single place to get well-organised screenshots from. I cropped each image so just a representative section of the window was present, here shown with a pinkish rectangle: Then used Pillow to get the average lightness of each cropped image: for file in sorted(os.listdir('.')): image = Image.open(file) greyscale = image.convert('L') stat = ImageStat.Stat(greyscale) avg_lightness = int(stat.mean[0]) print(f"{file}\t{avg_lightness}") This ignores any kind of perceived brightness or the tinting that MacOS has been doing for a while based on your wallpaper colour. I could go down a massive tangent trying to work out exactly what the best way to measure this is, but given that the screenshots aren’t perfectly comparable between versions, comparing the average brightness of a greyscale image seems reasonable. I graphed that on the release year of each OS version, doing the same for dark mode: 2009 2025 100% 0% This graph is an SVG, which may not render correctly in feed readers. View this post on the web. You can clearly see that the brightness of the UI has been steadily increasing for the last 16 years. The upper line is the default mode/light mode, the lower line is dark mode. When I started using MacOS in 2012, I was running Snow Leopard, the windows had an average brightness of 71%. Since then they’ve steadily increased so that in MacOS Tahoe, they’re at a full 100%. What I’ve graphed here is ju...