When I work with bold colors in Illustrator I get these ugly edges between shapes. Both previewed in Illustrator and when exported (I have played around with different formats and settings).

I think it has always been like this, I just don't use such colors that often (or avoid). I feel like it has something to do with anti-aliasing and "blending with gamma" (I don't really know how to word this correctly, hope you understand), because without anti-aliasing it's not there. And if i copy the shapes to Photoshop and use "blend RGB colors using gamma" set to 1.0 in the color settings, it gets a little better.

I know this is not such a big problem for most, but it really distracts me to no end! Is there any way to remove it? Or just make it less noticeable?

Where the blue and red meet there's a dark ugly edge

  • I'm not sure if it's actually darker, or just the eye playing tricks. Those colors are "clashing", and are actually quite hard for me to look at for more than a second or two. This might help explain what's going on a little better: io9.gizmodo.com/5974960/…
    – Vicki
    Jan 6, 2016 at 19:41

2 Answers 2


This is not just a trick of the eye, although I'm sure it's part of what's going on.

So if you don't want to feel like some sort of pedantic freak, watch "Computer colour is broken" by MinutePhysics, which explains why your "blending with gamma" seems to help (note: it actually does).

For posterity, the video basically says: "most graphics software, including Illustrator, blends colours incorrectly, leading to grotty dark colours where colours butt up on antialiased or blurred images".

Unfortunately, currently I don't think there's any way to fix this while preserving your vectors, as linear blending is so widespread. However, if your end product can be pixels, I'd suggest putting up with it while you make the image, then transfer to photoshop to render with gamma blending (maybe try tweaking the gamma value to your taste, although be aware that the correct value is different for different monitors and OSes).


Regarding "making it less noticable", you might be able to mitigate the effect with a tiny "hairline" outline that lies over the boundary between the colours, which has a colour that compensates for the murkiness of the linear blending. In your case, I'd expect it to be a very bright magenta/purple, but you'll have to tweak the colour to get a good result.

Importantly, the line should be thin enough that you barely see it, and the colour bright enough that it still has effect. You might have to overlay several of these "hairlines", as a single line might not be able to get bright enough.

Here's a rough attempt, which met some success I think. Make sure you view it at 100%.

Blend compensation fix


It's not about the file or the format you're using. This 'dark blue' thin line is due to how your eyes perceive light and how your brain 'reads' it.

So, as far as I know, there is no way to work around this (unless you can bio-engineer the next Human species).

  • 1
    Would it be theoretically possible to somehow trick the brain to not see it?
    – Mathis
    Jan 6, 2016 at 17:00
  • @mathis, not without adding a gap or color between as a buffer of sorts.
    – BrianC
    Jan 6, 2016 at 22:03

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