
How to Avoid Equidistant HSV Colors (2011) - Tomte
https://www.vis4.net/blog/2011/12/avoid-equidistant-hsv-colors/
======
ggm
I had a very interesting sequence of exchanges in MBONE about this problem, in
the 1990s.

The problem was the use of colour in distributed editing systems like Van
Jacobsens 'whiteboard'

(it was an exemplar tool we used in the Internet multicasting activity then)

and their projection of color values into greyscale monitors (a class of
terminal which probably doesn't exist any more but at the time, there was a
distinction between pixel quality and size and density in greyscale and
colour. greyscale was finer but limited to .. shades of black and white)

We discussed perceptual colour differences, mapping into grey, the loss of
information. Choosing a sequence of colours which were distinct but formed
grey tones which were also distinct is .. hard.

~~~
im3w1l
> Choosing a sequence of colours which were distinct but formed grey tones
> which were also distinct is .. hard.

Start backwards? And then give them hues?

~~~
ggm
Not a bad approach. they also have to be visually satisfying choices in colour
and you kind of want the rainbow.

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waste_monk
>For instance, in the following HSL color scale the brightness step between
the second and the third red appears much bigger than the step between the 3th
and 4th color. Even worse, this effect seems to differ across different hues,
as the comparison to the blue scale shows.

I honestly can't see what they're talking about in the example images. Is this
a "some people are more visually sensitive than others" type thing, or is this
the visual equivalent of audiophiles messing about with bespoke setups to try
and get marginal improvements in sound quality?

~~~
Reelin
The difference should be readily visible. Various aspects of visual
sensitivity can certainly vary between people but I think it's far more likely
that your monitor isn't very well calibrated or is possibly just of low
quality.

In my case, the difference is barely visible on the profile I typically have
loaded because I modified it to maximize brightness and text legibility at the
expense of significant color accuracy.

~~~
Silhouette
I think the claim that the difference in the first pair was _much_ bigger was
probably overstated.

Would I say the difference appeared bigger in that case? Yes.

But on a calibrated screen, as someone with no known colour vision
deficiencies, and as someone who does a lot of design work including fine-
tuning colour schemes, there is a clear step between each adjacent pair of
reds on that scale to me, and the perceived differences between the steps
aren't _that_ big.

If I had to guess, I'd suggest that some people see the second red darker than
it should be due to poor colour reproduction on their monitor, which would
exaggerate the difference from second to third red.

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Daub
I just read the article. It nicely details the difference between physical
lightness and perceptual brightness. For a demonstration of this, try opening
a photo of colorful flowers in Photoshop. Compare a de-saturation in RBG with
one in Lab (Adjustments/Hu Saturation). The result from the Lab desaturation
will respect the perceptual differences of the hue of the flowers flowers.

------
Buetol
Looks like the link to the "I want HUE" tool is broken, here's the proper
link:
[http://medialab.github.io/iwanthue/](http://medialab.github.io/iwanthue/)

~~~
azepoi
I'm impressed by the other mentioned picker, for HCL this time
[http://tristen.ca/hcl-picker/](http://tristen.ca/hcl-picker/)

This tool is also useful
[https://vis4.net/palettes/#/9|s|00429d,96ffea,ffffe0|ffffe0,...](https://vis4.net/palettes/#/9|s|00429d,96ffea,ffffe0|ffffe0,ff005e,93003a|1|1)

I have to mention this fantastic presentation on colormaps
[https://www.youtube.com/watch?v=xAoljeRJ3lU](https://www.youtube.com/watch?v=xAoljeRJ3lU)
(A Better Default Colormap for Matplotlib, SciPy 2015, Nathaniel Smith and
Stéfan van der Walt). It is about perceptually uniform colormaps.
[https://bids.github.io/colormap/](https://bids.github.io/colormap/)

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hoseja
Seems similar but different to `pastel distinct`[0], maybe it would be a nice
addition.

[0] [https://github.com/sharkdp/pastel](https://github.com/sharkdp/pastel)

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ComputerGuru
hsluv is a much easier way of doing this in 2020. It was recently covered in
an article here on HN, too:
[https://news.ycombinator.com/item?id=22528760](https://news.ycombinator.com/item?id=22528760)

------
CyberDildonics
tldr - there is a color space called CIELab that is made so that euclidean
distances map to perceptual distances.

~~~
neilpanchal
There is also a CIELCH colorspace that allow you to still work in the CIE
colorspace but use familiar values of luminosity, chroma and hue. I created a
library for Processing/Java that allows the user to define colors in CIELCH
space [1].

[1]
[https://github.com/neilpanchal/Chroma](https://github.com/neilpanchal/Chroma)

~~~
RandyRanderson
This lib is fantastic - thanks!!

