This illusion was new to me. Does whichever dot you look at turn more purple?

Pretty neat how clearly this lets you see the reduced sensitivity to blue light in the very centre of your vision.

https://www.schulz-hildebrandt.com/9-purple-dots-illusion/

https://arxiv.org/abs/2509.11582

@Danpiker

Have a look at:

https://gamesx.com/misctech/visual.htm

Your eyes have much lower resolution in blue light than in red or green, the article demonstrates that increasing the size of the blue pixels by 9 times (3x3) makes an almost imperceptible change in the image. Link rot has taken the extra images and a diagram showing a proposed pixel layout of a big blue diamond surrounded by small red and green squares.

Human Visual Accuity: Your Eyes Suck at Blue

Human visual accuity in Blue

@PhilSalkie @Danpiker Huh. Does this means that we shouldn't be writing small text or rendering small details in blue?
@eliocamp @Danpiker
It probably means not just that but we should be compressing the blue layer much more than the green or red when doing lossy compression algorithms.
@PhilSalkie @eliocamp @Danpiker rgb565 is a somewhat common color mode for this reason - we see green with the most detail, so when you're looking to reduce bits per pixel it makes sense to cut the other two slightly

@groxx @eliocamp @Danpiker
Makes sense, there are a number of monochrome photosensors designed to work near the center of the green visual peak as well.

What I found interesting was not just being able to decrease the number of bits of blue intensity for each pixel, but making the pixel count so much less for blue. We've reached a point in tech where speaking about "efficiency" marks you as being from a bygone age - but this seems like it could be a neat way to pack more images into fewer bytes.

@PhilSalkie @eliocamp @Danpiker yea, I can't find the blog post I vaguely remember from long ago that had samples of all channels, but https://calebkruse.com/10-projects/seeing-blue/ looks like a decent demo near the bottom. it's kinda crazy.
Caleb Kruse - Focusing on Blue