film

90 Articles

Creating Customized Diffraction Lenses For Lasers

August 23, 2024 by 3 Comments

[The Thought Emporium] has been fascinated by holograms for a long time, and in all sorts of different ways. His ultimate goal right now is to work up to creating holograms using chocolate, but along the way he’s found another interesting way to manipulate light. Using specialized diffraction gratings, a laser, and a few lines of code, he explores a unique way of projecting hologram-like images on his path to the chocolate hologram.

There’s a lot of background that [The Thought Emporium] has to go through before explaining how this project actually works. Briefly, this is a type of “transmission hologram” that doesn’t use a physical object as a model. Instead, it uses diffraction gratings, which are materials which are shaped to light apart in specific ways. After some discussion he demonstrates creating diffraction gratings using film. Certain diffraction patterns, including blocking all of the light source, can actually be used as a lens as the light bends around the blockage into the center of the shadow where there can be focal points. From there, a special diffraction lens can be built.

The diffraction lens can be shaped into any pattern with a small amount of computer code to compute the diffraction pattern for a given image. Then it’s transferred to film and when a laser is pointed at it, the image appears on the projected surface. Diffraction gratings like these have a number of other uses as well; the video also shows a specific pattern being used to focus a telescope for astrophotography, and a few others in the past have used them to create the illusive holographic chocolate that [The Thought Emporium] is working towards.

Continue reading “Creating Customized Diffraction Lenses For Lasers” →

Spy Tech: Making Microdots

August 17, 2024 by 18 Comments

It isn’t just a spy movie trope: secret messages often show up as microdots. [The Thought Emporium] explores the history of microdots and even made a few, which turned out to be — to quote the video you can see below — “both easier than you might think, and yet also harder in other ways.”

If you want to hide a secret message, you really have two problems. The first is actually encoding the message so only the recipient can read it. However, in many cases, you also want the existence of the message to be secret. After all, if an enemy spy sees you with a folder of encrypted documents, your cover is blown even if they don’t know what the documents say.

Today, steganography techniques let you hide messages in innocent-looking images or data files. However, for many years, microdots were the gold standard for hiding secret messages and clandestine photographs. The microdots are typically no bigger than a millimeter to make them easy to hide in plain sight.

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Colour Film Processing For The 2020s Hacker

July 23, 2024 by 17 Comments

We’re now somewhere over two decades since the mass adoption of digital photography made chemical film obsolete in a very short time, but the older technology remains in use by artists and enthusiasts. There’s no longer a speedy developing service at you local mall though, so unless you don’t mind waiting for one of the few remaining professional labs you’ll be doing it yourself. Black-and-white is relatively straightforward, but colour is another matter. [Jason Koebler] has set up his own colour processing lab, and takes us through the difficult and sometimes frustrating process.

From an exhaustive list of everything required, to a description of the ups and downs of loading a Patterson tank and the vagiuaries of developer chemicals, we certainly recognise quite a bit of his efforts from the Hackaday black-and-white lab. But this is 2024 so there’s a step from days past that’s missing. We no longer print our photos, instead we scan the negatives and process then digitally, and it’s here that some of the good advice lies.

What this piece shows us is that colour developing is certainly achievable even if the results in a home lab can be variable. If you’re up for trying it, you can always automate some of the process.

Reviving A Sensorless X-Ray Cabinet With Analog Film

January 26, 2024 by 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” →

Darkroom Robot Automates Away The Tedium Of Film Developing

January 8, 2024 by 14 Comments

Anyone who has ever processed real analog film in a darkroom probably remembers two things: the awkward fumbling in absolute darkness while trying to get the film loaded into the developing reel, and the tedium of getting the timing for each solution just right. This automatic film-developing machine can’t help much with the former, but it more than makes up for that by taking care of the latter.

For those who haven’t experienced the pleasures of the darkroom — and we mean that sincerely; watching images appear before your eyes is straight magic — film processing is divided into two phases: developing the exposed film from the camera, and making prints from the film. [kauzerei]’s machine automates development and centers around a modified developing tank and a set of vessels for the various solutions needed for different film processes. Pumps and solenoid valves control the flow of solutions in and out of the developing tank, while a servo mounted on the tank’s cover gently rotates the reel to keep the film exposed to fresh solutions; proper agitation is the secret sauce of film developing.

The developing machine has a lot of other nice features that really should help with getting consistent results. The developing tank sits on a strain gauge, to ensure the proper amount of each solution is added. To avoid splotches that can come from using plain tap water, rinse water is filtered using a household drinking water pitcher. The entire rig can be submerged in a heated water bath for a consistent temperature during processing. And, with four solution reservoirs, the machine is adaptable to multiple processes. [kauzerei] lists black and white and C41 color negative processes, but we’d imagine it would be easy to support a color slide process like E6 too.

This looks like a great build, and while it’s not the first darkroom bot we’ve seen — we even featured one made from Lego Technics once upon a time — this one has us itching to get back into the darkroom again.

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three resin-printed Single8 film cartridges, uncropped image

Re-Inventing The Single 8 Home Movie Format

November 23, 2023 by 22 Comments

[Jenny List] has been reverse-engineering and redesigning the Single8 home movie film cartridge for the modern age, to breathe life into abandoned cine cameras.

One of the frustrating things about working with technologies that have been with us for a while is the proliferation of standards and the way that once-popular formats can become obsolete over time.  This can leave equipment effectively unusable and unloved.

There is perhaps no greater example of this than in film photography – an industry and hobby that has been with us for over 100 years and that has left many cameras orphaned once the film format they relied on was no longer available (Disc film, anyone?).

Thankfully, Hackaday’s own [Jenny List] has been working hard to bring one particular cine film format back from the dead and has just released the fourth instalment in a video series documenting the process of resurrecting the Single8 format cartridge. Continue reading “Re-Inventing The Single 8 Home Movie Format” →

Sometimes It’s Worth Waiting: Kodak Finally Release Their Super 8 Camera

November 23, 2023 by 32 Comments

Think of all those promised products that looked so good and were eagerly awaited, but never materialized. Have you ever backed a Kickstarter project in the vain hope that one day your novelty 3D printer might appear? Good luck with the wait! But sometimes, just sometimes, a product everyone thought was dead and gone pops up unexpectedly.

So it is with Kodak’s infamous new Super 8 camera, which they announced in 2018 and had the world of film geeks salivating over, then went quiet on. It’s abandoned, we all thought, and then suddenly five years later it isn’t. If you really must have the latest in analog film-making gear, you can put your name down to order one now.

Continue reading “Sometimes It’s Worth Waiting: Kodak Finally Release Their Super 8 Camera” →