esgeroth : stuff : color : stream
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Stream of consciousness

This color project is growing in scope and I need a place to just jot down my thoughts and findings without any particular structure. Welcome. I suppose you could call this "Pete's Color Log"

Fri, Oct 2, 2020

Here is my first picture of the visible spectrum:

Visible Light Spectrum

It's cropped out of the image below, which I took in my backyard this afternoon.

Visible Light Spectrum on a piece of paper

A couple days ago when I realized I felt a little serious about understanding colors, I ordered a four piece glass prism set. It arrived today:

Four glass prisms

There is nothing special about my picture of the spectrum, other than it being my own work. I still need to add a license to these pages, but I intend to license all this color work under the terms of CC BY-SA 4.0. I want everything I put here to be my own, especially any images. I don't know why, there are plenty of graphics with reasonable licenses I could reuse, but I feel like to understand what I'm doing, I have to do it all myself.

So what am I doing? Well, today, taking pictures of sunlight through a prism:

Prism in sunlight

It was actually trickier than I anticipated. Turning and moving the prism did not initially result in the changes in the visible spectrum that I was expecting. Hopefully with practice I can get some better images. Of course capturing those images in RGB won't fully capture the spectral colors visible, but alas...

Longer term, I want to put together a site that might help others understand colors and also put together some JavaScript to help in that effort and to also share for the purpose of doing fun color things. That first image at the top of this page is particularly satisfying, because when I open it in an image editor and use the eye dropper to pick out the colors, the hue value follows a nice linear progression as I go from left to right across the image.

A week ago I don't think I would have had the same appreciation for that. All I intended to do was document how I chose the color scheme for this website, but I found myself curious about more questions and needing to understand more concepts. The CIE 1931 color space suddenly makes a lot of sense to me after much reading, but wikipedia in this instance was too forward on formulas and not particularly useful for developing any sort of intuition.

So here I go documenting what I've learned, but because I want to recreate all the graphics I need myself, it's going to be slow going. This stream of conciousness will let me write things down unstructured, since it will probably take a few tries to get the structure right. Stay tuned.

Sat, Oct 3, 2020

Before I can start visualizing things, I need something to visualize with. To that end, since I'm caught up in this DIY mode, I have begun work on some JavaScript utilities. Today I am starting with some prototype level code, not encapsulating anything in functions yet. Doing this has reminded me how fun colors in JavaScript can be because of the rapid feedback. Here's what I've got so far:

  • 2D color map
    fill in a 2d plane via a callback that returns a color based on x and y coordinates.

Wed, Oct 7, 2020

Thu, Oct 8, 2020

I woke up at 4 am this morning and couldn't get back to sleep. When I gave up I started reading more about colors. Much material I already knew, but a few things became more prominent in their importance. Among them

  • The relative brightnesses of Green, Red, and Blue as perceived by humans
  • HSV and HSL being alternate representations of a particular RGB color space and not color spaces themselves
  • Saturation not being a particularly useful term because its meaning changes depending on context