Archive for the ‘Projects’ Category

Reflected Primary Colors

Monday, May 16th, 2022

Eyes are interesting things. We have color receptors in our eyes tuned for three different wavelengths. Short (blue), medium (green), and long (red). Our brains combine this information and allow us to perceive millions of color, which is really just amazing.

These three colors are so important, that we specifically target them when we produce images on our monitors and TVs. All the images are made up of these three colors. Just as importantly, when we capture images with cameras, we actually filter the light going into the cameras into the three primary colors.

Camera image sensors aren’t inherently color sensitive. Each pixel we get out of a camera is actually made up from information gathered from 4 sub-pixels on the digital camera sensor. Each sub pixel has a filter in front of it for light to pass through; 1 Red, 1 blue, and 2 green. This is called the Bayer Filter. After the camera takes a picture or records a frame, the sub pixels get interpolated together to give a single pixel of data.

(It’s probably more nuanced than that, but that is the general idea)

I recently purchased an RGB flashlight, and wondered how well I could reconstruct a color image by taking 3 photos illuminated with the different lights and combining them.

Ideally, I would like to try this using a black and white film camera, or black and white digital sensor, however I have access to neither, so I decided to use my iPhone.

The first method I used was to take color photos with each illumination, and layer them on top of each other using the add blend mode. Using this blend mode adds the RGB values together. For example:

This method works well. It’s somewhat surprising considering that nothing I used was color calibrated.

The second method that I was more excited about was taking black and white photos of each and using those as the raw channel data to reconstruct the image.

I took the photos on my iPhone while using the black and white filter mode. I then used Affinity Photo to import the photos and assign them to channels. The end result was abysmal.

I was able to improve it a bit by mixing the blue channel higher and reducing the intensity of the green channel.

Still not great.

I believe some of the problems are that the BW filter on the iPhone is not at all true black and white. I was surprised initially to find that the image wasn’t actually grayscale. It was RGB. I also don’t know how the image is being converted to black and white. It’s plausible that in the process of converting to grayscale, more red and blue data is thrown away in favor of green because it produces a better result to our eyes.

Although this was a bit of an interesting exercise, I think in the end it didn’t achieve great results because of the lack of true black and white sensor. The color results would have been more meaningful if it had been achieved without any color aware equipment.

Additionally, I’d be interested in comparing a composited photo using 3 exposures with red, green, and blue lights to a composited photo using 3 filters and white light. Someday I can revisit this experiment once I procure a proper camera.

Clarus the Dogcow

Tuesday, January 25th, 2022

For long-time Apple fans, hardly anything is more iconic than Clarus the Dogcow. Not quite a dog, not quite a cow, Clarus made her debut as part of the Cairo font set drawn by Susan Kare in 1983. Later on in the dogcow’s life, she found herself depicting the orientation of printer paper in the page setup dialog window for Mac OS. I don’t recall exactly in which version she made her debut, but sometime before System 7. And if you are the right age, you may even remember the brown incarnation of the dogcow appearing as a stamp in KidPix!

The dogcow even had official technical notes on Apple’s webpage back in the day! (though those documents were sadly removed in the mid 2000’s)

Naturally, I thought that the best way to commemorate Clarus’ impact on my childhood would be to replicate her likeness in wood. I made a template to follow and cut out strips of light and dark wood that were as uniform as I could make them. These strips of wood served as pixels to my arbor canvas. My dad and I took the little wooden pixels and layed them up against the paper template slowly building up Clarus’ familiar frame. The dark wood is ebony gaboon, and the light wood is maple.

After all the pieces were placed and we corrected any visible mistakes, glue was poured on top. The sides were clamped just enough to keep the pieces from moving. Bursts of air from an air compressor pushed the glue down between the wooden pixels, then finally the clamps were tightened.

Once it was dry, multiple slices were able to be taken from the resulting block of wood which would make the inlays for some miniature cutting board. Four in all were made. Using a CNC router, a rectangular inset was milled away from the maple cutting board, the corners squared up with a chisel, and the inlay glued into place.

All that was left was some sanding and finishing with a food-grade wax to complete these little cutting boards. Kind of a random thing to make, and I honestly can’t remember what made me want to do this in the first place. But I like my little dogcow cutting board and think to myself “moof!” every time that I use it.

Brisco County Jr. Orb Rod

Friday, September 10th, 2021

In 1993, The Adventures of Brisco County Jr. premiered on Fox. It was about a Bounty Hunter in the old west, and his mission to round up the gang of outlaws who killed his father, a famous Marshal. Brisco County is a Harvard educated lawyer who is eagerly looking to the future for the “coming thing”.

As he works to capture all the outlaws responsible for his father’s death, he has multiple encounters with a mysterious object only known as ‘the orb’. In the first episode we learn that the orb can grant power to people who possess it. As we continue through the season, we learn more about the orb’s power and origins, but its mystery isn’t completely unraveled until nearly the end of the season.

The orb is hard to describe. It’s a golden, spherical object with protrusions regularly distributed across it’s surface. These protrusions are the end-caps or glowing rods that can be removed from the orb. As a kid, I always thought that the orb’s mystery and power was very fantastic, and I always wanted to see it in person, or to own it.

Reference photo found on a prop auction site

I finally decided that it was time to replicate it. Not the whole thing, just one of the orb rods. I’ve done a bit of research here and there over the years and have never gotten a straight answer on the exact size of the prop. I managed to find a small image of a prop replica that was built from the same mold as the original prop. Luckily, this prop happened to be photographed next to a ruler. I inferred the measurements to the best of my ability and concluded that the prop orb rod is about 1.5 inches in diameter, and about 13.25 inches long.

Brisco County Orb Rod Plans

I was able to find blue acrylic rod in 1.5 inch diameter from a supplier on eBay for a good price. I then bought some Brass stock on Amazon, also 1.5 inches in diameter.

I don’t have any tooling for doing a rounded end of this diameter, so I used the lathe to create steps at 1/8 inch intervals in the brass that match the contour of a .75 inch radius sphere. I then used a file to smooth it down to a nice rounded end. A little bit of sanding, and then a clear coat of lacquer to prevent tarnishing, and the cap is finished. The reverse side was drilled out to 1 inch to accommodate the acrylic rod.

There wasn’t much to do on the acrylic rod, except to machine down one end in order to insert it into the cap. Additionally, the other end was fairly rough from being cut off with a band-saw by the seller. I used progressively finer sand paper on the end, finishing with a 2000 grit wet sanding to get it to be a clear and smooth as possible.

The last step was to epoxy the cap onto the acrylic rod.

Finally, after many decades, I have the prop replica I’ve always dreamed about.

Sadly, Brisco County Jr. was cancelled in its first season. Despite being cancelled, I find it to be an enduring show full of the witty one-liners you’d expect from Bruce Campbell, the charm of old spaghetti westerns, and a touch of sci-fi. Luckily, the show was able to satisfyingly conclude it’s storyline, so even while it was cancelled, it feels complete, and is one show that I frequently rewatch.