I'm Blue

Designers are used to getting vague direction from clients. "It should have more pop!" or "Can you make the blue more blue?" But Kevin was a contractor who worked on embedded software, so he didn't really expect to have to deal with that, even if he did have to deal with colors a fair bit.

Kevin was taking over a contract from another developer to build software for a colorimeter, a device to measure color. When companies, like paint companies, care about color, they tend to really care about color, and need to be able to accurately observe a real-world color. Once you start diving deep into color theory, you start having to think about things like observers, and illuminants and tristimulus models and "perceptual color spaces".

The operating principle of the device was fairly simple. It had a bright light, of a well known color temperature. It had a brightness sensor. It had a set of colored filter gels that would pass in front of the sensor. Place the colorimeter against an object, and the bright light would reflect off the surface, through each of the filters in turn and record the brightness. With a little computation, you can determine, with a high degree of precision, what color something is.

Now, this is a scientific instrument, and that means that the code which runs it, even though it's proprietary, needs to be vetted by scientists. The device needs to be tested against known samples. Deviations need to be corrected for, and then carefully justified. There should be no "magic numbers" in the code that aren't well documented and explained. If, for example, the company gets its filter gels from a new vendor and they filter slightly different frequencies, the commit needs to link to the datasheets for those gels to explain the change. Similarly, if a sensor has a frequency response that means that the samples may be biased, you commit that with a link to the datasheet showing that to be the case.

Which is why Kevin was a little surprised by the commit by his predecessor. The message read: "Nathan wants the blue 'more blue'? Fine. the blue is more blue." Nathan was the product owner.

The corresponding change was a line which read:

blue += 20;

Well, Nathan got what he wanted. It's a good thing he didn't ask for it to "pop" though.

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