Printed circuit boards were once so simple. One or two layers of copper etched on a rectangular fiberglass substrate, with a few holes drilled in key locations so components could be soldered into place. They were functional objects, nothing more—built only for the sake of the circuit itself.
Fast forward to today, and so much has changed. Boards sprout so many layers, often more than 10, and all kinds of fancy geometric features for purposes both practical and pretty. But what catches they eye more than that, other than rich, saturated color? [Joseph Long] came to the 2024 Hackaday Supercon to educate us on the new world of full color PCBs.
[Joseph] begins his talk with an explanation of terminology. We often look at a PCB and cite its color—say, green for example. As [Joseph] explains, the color comes from the solder mask layer—so called for its job in ensuring solder can only go where it’s supposed to go. The solder mask sits atop the copper layer, but beneath the silk screen which has all the component outlines and part labels.
Solder mask was traditionally green, and this is still the most common color you’ll find in the majority of electronics. However, in recent decades, the available gamut of colors has increased. Now, you can routinely order yellow, blue, purple, and red solder masks quite easily, as well as black or white if you’re so inclined. As some creative makers have found, when designing a board, it’s possible to get several colors into a design even if you’re just using one color of solder mask. That’s because the solder mask appears in slightly different shades when it’s laid over the bare fiberglass of the PCB, versus being laid over copper, for example. Add in white silkscreen and you’ve got quite a lot to work with.
Different colors are achievable on a PCB even just by using a single soldermask color.
We’re used to having a choice of color on our PCB orders today, but so much more is possible.
But what if you want more? What if you want real color? [Joseph] realized this could be possible when he found out that PCB board houses were already using inkjet-like printers to lay down silkscreen layers on small-run boards. Since there was already a printer involved in the board production process, wouldn’t it be simple to start printing on circuit boards in full color?
As it turns out, this was very practical. Two big Shenzhen board houses—JLCPCB and PCBWay—both started delivering color printed boards in 2024. The method involved using a white solder mask layer, with a full-color “silkscreen” layer printed on top using UV-cured ink. Using this ink was a particular key to unlocking full color PCBs. The UV-cured inks are more robust under the tough conditions PCBs face, such as the high temperatures during reflow or hand soldering.
Color printing PCBs might sound trivial and only relevant for cosmetic purposes, but [Joseph] points out it has lots of practical applications too. You can easily color code pinouts and traces right on the the board, a feature that has obvious engineering value. You can even use photorealistic footprints to indicate where other board-level modules should be soldered in, too, making assembly more intuitive. Plus, full color boards are fun—don’t discount that!
[Joseph] likes using the full-color prints to aid in assembly, by using far more realistic footprints for items like board-scale modules and batteries.[Joseph] is also a big fan of the SAO format, having designed several compatible boards himself. At his talk, he showed off special “extender” boards of his own creation and offered giveaways to attendees.
If you’re wondering how to get started, [Joseph]’s talk covers all the important ground. He goes over the workflow for doing color PCBs with typical board houses. As the main suppliers in this area, PCBWay and JLCPCB both have slightly different ways of working with design files for color boards. Obviously, creating a color board involves making images outside of your traditional board design software. It’s straightforward enough, but you have to follow some careful practices to ensure your images are printed in the right size and right orientation to match the rest of your PCB design. PCBWay lets you make your own images and submit them with your Gerber files from whatever board design tool, while JLCPCB requires you to produce your PCB within their EasyEDA design software and put the graphics directly in there. [Joseph] also explains the costs involved for printing these boards, which does come at a premium relative to traditional boards.
As a bonus, we even get to see some of Joseph’s awesome color boards. The graphics are stunning—they really show the potential of full-color PCBs and how they can elevate a project or a fun badge design. If you’re eager to try this out, go ahead and watch [Joseph]’s primer and dive in for yourself!
This articles is written by : Nermeen Nabil Khear Abdelmalak
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By Nermeen Nabil Khear 
