Introduction: Film Negative Necklace

While Polaroid instant cameras have made a come-back in recent years, the vast majority of photography is still digital, leaving those of us who grew up in the age of film cameras stuck with shoe boxes full of old prints and developed film negatives.

In my case, I had a notebook of developed film leftover from my wet photography class in college that I'd hung onto with the intention of one day digitizing. It seemed like a shame that they were collecting dust, especially when some of the images were somewhat artistic, and so I decided to try and find an unconventional way to feature and reuse the film negatives.



  • 3D printer with your choice of filament
  • Drill
  • Soldering iron
  • Scissors
  • Pen or pencil


Step 1: Creating the Light Box Pendant


The light box--or necklace pendant--is composed of two parts designed in Tinkercad [Image 1.1]. The front piece [Image 1.2] is where the film will be displayed, and the back piece [Image 1.3] will support the LEDs and battery.

I intentionally designed the light box so that the lilypad battery holder will be exposed on the backside for easy access to the on/off switch and for unobstructed battery replacement. While I contemplated hiding the lilypad inside the miniature light box, like a locket, I found that methods used to make it open and close for access to the switch and battery, such as hinges or magnets, would have increased the size of the pendant, and I wanted to make it as sleek as possible.


I printed the pendant using PLA filament on my Ender Pro3 [Image 1.4]. The .STL file is attached to the Supplies section of this Instructable, but I've also included the pendant dimensions in the above images in case you would prefer to hand-construct it out of some other material.

Step 2: Painting the Pendant

If you 3D print your pendant pieces in the color of your finished design, you can skip this step. I didn't have any black filament on hand, so I used a Rust-oleum primer in flat black [Image 2.1] to paint the pendant pieces my desired color [Image 2.2]. If you choose to paint your 3D printed design, ideally select something that will bond well with plastic and let it dry [Image 2.3] before continuing.

Step 3: Inserting the Lilypad

Once the paint on the pendant has dried, it's time to add the electronics to the back piece of the miniature light box. We begin by sliding the Lilypad battery holder into the groves on back piece so that the on/off switch is at the top [Image 3.1]. Use a pen or pencil to mark where the Lilypad positive and negative connection holes on the back of the pendant [Image 3.2]. Remove the Lilypad from the pendant [Image 3.3] and use a drill to create holes where you made your marks [Image 3.4].

Add superglue to the back of the pendant in the center of the four holes [Image 3.5], slide the Lilypad back into place [Image 3.6], and let the glue dry.

Note: It is important that you position the Lilypad so that the on/off switch is at the top. Otherwise, replacing the battery will be impossible.

Step 4: Adding the LEDs

The Lilypad is composed of two positive connections located at the top near on/off switch and two negative connections positioned at the bottom, so I began with a circuit composed of one LED per pair of positive and and negative holes [Image 4.1].

To attach the LEDs, I began by bending the legs of a 3mm LED so that they were split 180-degrees [Image 4.2]. I then added a 90-degree bend to each of the legs and fed the legs into the drilled holes on backside of the pendant and out through the positive and negative connections on the Lilypad [Image 4.3]. Repeat the process for the second LED, ensuring the anodes (long leg) are attached to the positive connections, and the cathodes (short leg) fed into the negative holes on the Lilypad [Image 4.4]. Once the two LEDs had been inserted into the Lilypad, I bent the tips of the anodes and cathodes over the outside edge of the Lilypad to secure them in place [Image 4.5] before soldering the LEDs to the Lilypad for a secure connection [Image 4.6].

At this point you can move on to the next step or, if you're like me and want more light, you can add a second pair of LEDs to the circuit [Image 4.7] by soldering them directly to the legs of the LEDs already installed on the pendant [Image 4.8]. Attach anode to anode and cathode to cathode, and avoid negative and positive connections from touching. If you have any excess wire handing over the edges of the pendant, clip it away with some wire cutters.

Step 5: Adding the Film Negative

First, cut a piece of clear plastic or plexiglass into a 33mm X 33mm square [Image 5.1]. (I used an old plastic candy mold I had stashed away in my craft supplies.) Add superglue to the inside rim of the front piece to the light box and press the plastic square into place [Image 5.2].

Note:There is limited space inside the pendant because of the LEDs, so select a plastic that is 2-mm or less in thickness.

Second, trim your film negative down to 33mm X 33mm [Image 5.3], add drops of superglue sparingly to the corners of the inside frame on the backside of the clear plastic, and place the film negative inside the front of the pendant and behind the plastic [Image 5.4].

Third, cut a piece of white paper into a 33mm X 33mm square [Image 5.5]. Standard printer or parchment paper works well for this step. Add a little more glue to the backside of the film negative and add the paper to diffuse the light from the LEDs [Image 5.6].

Let the glue dry.

Step 6: Finishing the Pendant

Add superglue around the LEDs along the outer rim of the back piece of the light box pendant [Image 6.1]. Align the front of the pendant with the back so that the LEDs are sandwiched between the two pieces, and press them together until the glue dries and the two pieces are securely attached [Image 6.2].

Loop a necklace chain through the clasp on the pendant [Image 6.3], and your film box necklace is complete!

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