Color Tool | Hacker News Reader

Color Tool

colorusage.arc.nasa.gov

73 pointsTomte16 comments

This tool looks like it employs the Munsell color space, invented by Albert Munsell, one of the Demi-gods of color science. Munsell was a painter, and a pretty good one. He was frustrated by the arbitrary naming of artists paints, so he set out to develop a perception-based system of his own. It was based on two principles: ‘smallest perceivable difference’ and ‘pair-wise comparison’. Using this, and hundreds of test subjects, he mapped perceptual color space. Until then, it had been assumed it was spherical. He showed it for what it really was: lumpy and uneven. Also, fundamentally non-Euclidean. A true pioneer.

As a 13 year old, I read this paper [0] by Lorenzo Ridolfi when it came out and it really inspired me to explore stuff like this. Every few years I'm reminded of it and I try recreating the programs outside of MATLAB. The 3D manifolds he creates are really fantastic, you can see the nonlinearity of human vision causing wrinkles in the surface where optimization breaks down.

[0]: https://www.semanticscholar.org/paper/Investigating-Euclidea...

Will Certainly check that paper out. 13 years old? Pretty precocious.

A great book to read on the subject of color spaces is ‘color space and its divisions: Color Order from Antiquity to the Present’ by Rolf Kuehmi. I have read just about every major book on color there is, and this one is easily amongst the best. Written in plain English and with great insight. Go with him to a place beyond RGB.

Thanks for the reference. It is a subject I would like to know more about.

Let me comment, though, that I've never before seen a review that says that a book from a reputable publisher is bound with the pages at random: https://www.amazon.com/Color-Ordered-Systems-Antiquity-Prese... . In addition I see that there are three reviews, two 5's and a 1, and Amazon says "5 star" is 53%. Hmmm.

Munsell's amazing! This similar to Munsell, but where his space was based on specific, literal sample colors, this one is based on a mathematical model -- but the experiments to determine that model were remarkably similar to his!

The core model is CIE Lab: https://en.wikipedia.org/wiki/CIELAB_color_space

The a and b* parameters of that model are not totally intuitive, though; luckily, the same space expressed in polar coordinates has parameters that map really well to the same hue, chroma, and lightness that Munsell organized with.

I have used Lab space in Photoshop a bit. You are right... it is a relative to Munsell. Lab has one or two very particular uses in color adjustment. For example... as lightness is completely separate to chromacity, it is a very agreeable space for lightness and saturation adjustments.

It is also great for demonstrating to students how the perceptual Lightness value of a hue differs to the lightness value indicated by a desaturation in simple RGB space.

To use this tool on modern Chrome you can use our CheerpJ Applet Runner extension: https://chrome.google.com/webstore/detail/cheerpj-applet-run...

Runs legacy Java applets fully client side with no plugin.

I built a similar LCH space explorer, which doesn't require Java:

http://palette.sambleckley.com/

I use it pretty often; it's easy to ensure accessible contrast, etc, when L values are consistent.

Firing up Netscape Navigator on my Macintosh right now.

I use http://colorizer.org.

This is a nice tool. It has a great range of color spaces. However, the problem I have with it and similar tools is the schemes. These so-called harmonic combinations have a long history, but are almost entirely unsupported by science. Certainly, many high-order images such as paintings and movies employ basic RYB compilatory pairs (red/green, yellow/purple etc), but beyond that their arrangements ate fairly arbitrary.

You may need to fire up Netscape to get this applet working.

> Internet Explorer or Netscape: The Color Tool needs Apple's "Mac Runtime for Java"

The system requirements are indeed a time capsule of their own. Internet Explorer 6, Netscape 7, and Mozilla 1.4 (I miss that browser! Reminds me of Phoenix too, plus other lost browsers - Galeon, for one).

The Mac version "requires a PowerPC with 32 MB of RAM and Mac OS 7.6.1 or later."

Is the source code for this available? I couldn't find anything on the site or by looking through https://code.nasa.gov or https://opensource.gsfc.nasa.gov

It's very easy to decompile Java bytecode unless it's obfuscated. Not sure about legal aspects, but technically if you need source code, it's almost there.

using lightness-normalized colors for my web designs improved the overall balance a lot

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