Zink Is Zero Ink — Sort Of

March 31, 2025 by Al Williams 37 Comments

When you think of printing on paper, you probably think of an ink jet or a laser printer. If you happen to think of a thermal printer, we bet you think of something like a receipt printer: fast and monochrome. But in the last few decades, there’s been a family of niche printers designed to print snapshots in color using thermal technology. Some of them are built into cameras and some are about the size of a chunky cell phone battery, but they all rely on a Polaroid-developed technology for doing high-definition color printing known as Zink — a portmanteau of zero ink.

For whatever reason, these printers aren’t a household name even though they’ve been around for a while. Yet, someone must be using them. You can buy printers and paper quite readily and relatively inexpensively. Recently, I saw an HP-branded Zink printer in action, and I wasn’t expecting much. But I was stunned at the picture quality. Sure, it can’t print a very large photo, but for little wallet-size snaps, it did a great job.

The Tech

Polaroid was well known for making photographic paper with color layers used in instant photography. In the 1990s, the company was looking for something new. The Zink paper was the result. The paper has three layers of amorphochromic dyes. Initially, the dye is colorless, but will take on a particular color based on temperature.

The key to understanding the process is that you can control the temperature that will trigger a color change. The top layer of the paper requires high heat to change. The printer uses a very short pulse, so that the top layer will turn yellow, but the heat won’t travel down past that top layer.

The middle layer — magenta — will change at a medium heat level. But to get that heat to the layer, the pulse has to be longer. The top layer, however, doesn’t care because it never gets to the temperature that will cause it to turn yellow.

The bottom layer is cyan. This dye is set to take the lowest temperature of all, but since the bottom heats up slowly, it takes an even longer pulse at the lower temperature. The top two layers, again, don’t matter since they won’t get hot enough to change. A researcher involved in the project likened the process to fried ice cream. You fry the coating at a high temperature for a short time to avoid melting the ice cream. Or you can wait, and the ice cream will melt without affecting the coating.

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Retrogadgets: Oscilloscope Cameras

November 11, 2024 by Al Williams 23 Comments

Today, if you want to get a picture from your oscilloscope — maybe to send to a collaborator or to stick in a document or blog post — it is super easy. You can push an image to a USB stick or sometimes even just use the scope’s PC or web interface to save the picture directly to your computer. Of course, if it is on the computer, you could use normal screen capture software. But that hasn’t always been the case. Back in the days when scopes were heavy and expensive, if you wanted to capture an image from the tube, you took a picture. While you might be able to hold up your camera to the screen, they made specific cameras just for this purpose.

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Polaroid In An Instant

July 31, 2024 by Al Williams 23 Comments

Edwin Land, were he alive, would hate this post. He wanted to be known for this scientific work and not for his personal life. In fact, upon his death, he ordered the destruction of all his personal papers. However, Land was, by our definition, a hacker, and while you probably correctly associate him with the Polaroid camera, that turns out to be only part of the story.

It was obvious that Land was intelligent and inquisitive from an early age. At six, he blew all the fuses in the house. He was known for taking apart clocks and appliances. When his father forbade him from tearing apart a phonograph, he reportedly replied that nothing would deter him from conducting an experiment. We imagine many Hackaday readers have similar childhood stories.

Optics

He was interested in optics, and at around age 13, he became interested in using polarized light to reduce headlight glare. The problem was that one of the best polarizing crystals known — herapathite — was difficult to create in a large size. Herapathite is a crystalline form of iodoquinine sulfate studied in the 1800s by William Herapath, who was unable to grow large sizes of the crystal. Interestingly, one of Herapath’s students noticed the crystals formed when adding iodine to urine from dogs that were given quinine.

Land spent a year at Harvard studying physics, but he left and moved to New York. He continued trying to develop a way to make large, practical, light-polarizing crystals. At night, he would sneak into labs at Columbia University to conduct experiments.

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Reviving A Sensorless X-Ray Cabinet With Analog Film

January 26, 2024 by Dan Maloney 12 Comments

In the same way that a doctor often needs to take a non-destructive look inside a patient to diagnose a problem, those who seek to reverse engineer electronic systems can greatly benefit from the power of X-ray vision. The trouble is that X-ray cabinets designed for electronics are hideously expensive, even on the secondary market. Unless, of course, their sensors are kaput, in which case they’re not of much use. Or are they?

[Aleksandar Nikolic] and [Travis Goodspeed] strongly disagree, to the point that they dedicated a lot of work documenting how they capture X-ray images on plain old analog film. Of course, this is nothing new — [Wilhelm Konrad Roentgen] showed that photographic emulsions are sensitive to “X-light” all the way back in the 1890s, and film was the de facto image sensor for radiography up until the turn of this century. But CMOS sensors have muscled their way into film’s turf, to the point where traditional silver nitrate emulsions and wet processing of radiographic films, clinical and otherwise, are nearly things of the past. Continue reading “Reviving A Sensorless X-Ray Cabinet With Analog Film” →

You Can Now Build Your Own Polaroid-style Pack Film Cartridge

November 17, 2023 by Jenny List 5 Comments

Instant photography was one of the twentieth century’s coolest-to-have consumer inventions, but when the digital photography revolution came it had few answers. It survives as a niche format thanks to Fuji’s Instax line and a group of Dutch entrepreneurs who revived a defunct Polaroid works, but what hasn’t made it are the earlier pack and roll film formats for which the picture is revealed by peeling apart a negative and positive side. All isn’t lost though, because a small Austrian company has been producing pack film cartridges as a handmade artisan product. To reduce the cost per print they’re now available as a DIY self-assembly kit, and it’s this which [In an Instant] is taking a look at in their latest video.

The kit has enough components for eight shots, and where the original cartridge would have held multiple exposures this one can only hold one at a time. The cartridge itself is cleverly formed from folded card as opposed to the plastic and metal of the original, and the components are a relatively straightforward assembly task. It’s a fascinating window into how the Polaroid pack film process worked, with the light-sensitive layer behind a pull-away black light screen, in front of the white positive sheet and with a pouch of developer chemicals to one side. It’s in no way cheap at somewhere about 10 dollars a shot, but it’s amazing that pack film can be recreated and for enthusiasts it’s a lifeline that keeps their cameras useful.

This isn’t the first time we’ve looked at revitalising a pack film camera, but it’s a lot easier than hacking a Fuji cartridge to do the job.

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Converting A Polaroid SX70 Camera To Use 600 Film

October 20, 2023 by Lewin Day 4 Comments

These days, it’s possible to buy a number of different Polaroid instant cameras new off the shelf. That’s largely thanks to the retro resurgence that has buoyed interest in everything from vinyl records to analog synthesizers. However, if you’re truly old-school, you might still be rocking a vintage Polaroid SX-70 camera. Thankfully, there’s a way to convert these old rigs to work properly with the more popular modern 600 film.

The interesting thing about the SX-70 camera design is that its shutter speed and aperture setting are essentially linked together as the aperture and shutter assembly are combined into one unit with a variable tear-drop shaped opening. Thus, the timing of the shutter opening and closing and the extent to which it opens are what determines exposure and aperture.

Thankfully, [Jake Bright] has learned a lot about these unique cameras and exactly how this complex system operates. He shares his tips on firstly restoring the camera to factory-grade operation, and then the methods in which they may be converted to work with modern film. Fundamentally, it’s about changing capacitors or resistors to change the shutter/aperture timing. However, do it blindly and you’ll have little success. You first need to understand the camera’s mechanics, pneumatics, and its “Electric Eye” control system before you can get things dialed in just so.

We’ve seldom seen such a great deep dive into a camera outside of full-fat engineering documentation. [Jake] should be commended on his deep understanding and command of these fine instant cameras from yesteryear. May the Polaroid picture never die. Video after the break. Continue reading “Converting A Polaroid SX70 Camera To Use 600 Film” →

Polaroid Develops Its Pictures Remotely

August 16, 2023 by Bryan Cockfield 8 Comments

For those who didn’t experience it, it’s difficult to overstate the cultural impact of the Polaroid camera. In an era where instant gratification is ubiquitous, it’s easy to forget that there was a time when capturing a photograph meant waiting for film to be developed or relying on the meticulous art of darkroom processing. Before the era of digital photography, there was nothing as close to instant as the Polaroid. [Max] is attempting to re-capture that feeling with a modified Polaroid which instantly develops its pictures in a remote picture frame.

The build is based on a real, albeit non-functional, Polaroid Land Camera. Instead of restoring it, a Raspberry Pi with a camera module is placed inside the camera body and set up to capture pictures. The camera needs to connect to a Wi-Fi network before it can send its pictures out, though, and it does this automatically when taking a picture of a QR code. When a picture is snapped, it sends it out over the Internet to wherever the picture frame is located, which has another Raspberry Pi inside connected to an e-ink screen. Once a picture is taken on the camera it immediately shows up in the picture frame.

To help preserve the spirit of the original Polaroid, at no point is an image saved permanently. Once it is sent to the frame, it is deleted from the camera, and the next picture taken overwrites the last. And, for those who are only familiar with grayscale e-ink displays as the integral parts of e-readers, there have been limited options for color displays for a while now, as we saw in this similar build which was painstakingly built into a normal-looking picture frame as part of an attempted family prank.

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