Category Archives: graphics

fun, graphics, perception hacking, visualization

Fun with Pseudocolor, Part Two

A more perceptually-uniform, if less pretty, pseudocolor scheme.
A more perceptually-uniform, though arguably less pretty, pseudocolor scheme.

Inspired by this brilliant interactive demo of the perceptually uniform CIE L*a*b* color space, I decided to try a L*a*b* version of my pseudocolor scheme. I don’t find this version as pretty to look at, but it has the advantage that higher values are always mapped to colors that are perceptually brighter than lower values. In other words, if you squint at the image above, the bright and dark regions correspond pretty much exactly to what you’d see if it were greyscale. (For the L*a*b* to RGB conversion, I grabbed pseudocode from this handy page.)

L*a*b* space is much bigger than RGB space, so the spiral gets clipped against the edge of the cube in some places.
L*a*b* space is much bigger than RGB space, so the spiral gets clipped by the sides of the cube in a few places.
If you crank up the saturation, you do get more vivid colors, at the cost of a lot more clipping.
If you crank up the saturation, you do get more vivid colors, at the cost of a lot more clipping.
fun, graphics, visualization

Fun with Pseudocolor

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Screen Shot 2015-03-17 at 10.14.36 AM

A shader experiment gone horribly, beautifully wrong.

I was tinkering with some GLSL shaders in Processing, and I needed a way to visualize a value that smoothly changes from 0 to 1, showing a lot more than the 256 levels of gray that you’d normally see. So I wrote a little pseudocolor function that spirals through colorspace from black to white, hitting various hues along the way. It’s fun, and pretty, and very rungy-chungy, so I thought I’d post it here.

vec4 pseudo3(float val) {

    float reps = 20.0;
    float pi = 3.14159256;
    float bright = val;
    float con = 0.25 - 0.20 * cos(val * pi * 2.0);
    float sat = 0.66 - 0.25 * cos(val * pi * 2.0);

    return vec4(sin(val*pi*reps)*con+bright,
                sin(val*pi*reps - pi*0.663 * sat)*con+bright,
                sin(val*pi*reps - pi*1.333 * sat)*con+bright,
                1.0);
}

Here's the path the above function traces through the RGB cube of colorspace.
Here’s the path the above function traces through the RGB cube of colorspace.

animation, effects, graphics, self-reference, video

MTV Top 20 Video Countdown (1994)

MTV Top 20 Video Countdown (1994) from Cassidy Curtis on Vimeo.

In the 1990’s, it was typical for production companies to start their demo reels with a clock-wipe countdown. Some companies would use this as an opportunity to say something about their style, and do custom animation. (Will Vinton Studios, I remember, had a particularly cool stop-motion countdown at that time.) I thought it would be cool for Xaos to have a countdown that reflected our particular style of work, so I created this drippy ink effect counting down from 10 to 1, and a drippy version of the Xaos logo, which we put at the beginning and end of our demo reel respectively.

Some time after this, our producer got a call from MTV. They had this show called “Top 20 Video Countdown”. They wanted to use this effect for the bumpers and interstitials. Could we add the numbers 11 through 20? Our producer said “of course”, and charged them a lot of money. But it didn’t really take me that long.