Why is PCB Green?

It's not necessary for printed circuit boards to be green. Using different colors to distinguish or customize different PCBs might have several advantages. PCBX offers conventional colored PCBs in Green, Blue, Black, Red, and White, as well as bespoke colors or corporate hues upon request.

Why Are PCBs Usually Green?

Now, let's talk about PCB colors. If you want to gain more professional knowledge, please read the content below.

Green Reduces Visual Fatigue and Improves Inspections

At the dawn of technology, due to the technological development level at that time, quality control testing relied on workers checking the boards manually with their naked eyes. It's exhausting to gaze over small circuits all day, yet both neurologists and psychologists agree that the wavelength of green light relaxes the body and reduces weariness. Furthermore, they discovered that human eye sensors, known as cones, are especially sensitive to green light. As a result, there will be more contrast between the circuit traces, pads, silkscreen printing, and blank spaces. When viewing the boards from the outside, it is clear that faults in the outer layers are immediately identifiable. The increased contrast makes it easy to find errors This is evident from green-colored boards compared to other colors like blue, yellow, black, or white.

The Military Role in PCB Development

People tend to believe that the color green was chosen due to the military. The color ranges of PCBs were even researched by the United States military, which concluded that green was the best color, especially after testing the Boards under unfavorable conditions. According to this research, the military standardized PCBs as green in hue. Because the companies who created the boards for the military also made them for non-military entities, there was little need to make boards in different colors because most PCBs are hidden from the end users.

Cost Efficiency

Solder masks are created using a silkscreen process, in which a large volume of oil is splattered onto a screen mesh, followed by the circuit board underneath. The application is then withdrawn to dry before being reapplied under the mesh. Because the industry's major goal was to reduce costs, green PCBs were standard because other colors were more expensive to create.

When a different color solder mask is necessary, the excess solder mask oil must be removed from the silkscreen and cleaned before the new color can be placed. Adding more silkscreen stations for other colors is another alternative, although this usually generates chemical waste if it is not in use regularly, which reduces time and efficiency.

Contrast

A white silkscreened ident is frequently printed on the component side of rigid boards, and green gives the highest contrast for this layer, allowing human-readable writing. Peter Skippings, one of the co-founders of Artetch Circuits in the late 1960s, stated that green possessed the appropriate heat resistance for the roller tinning process for exposed copper pads on the board. Thus, only green was utilized because it met all operating requirements satisfactorily.

Are Green PCBs Necessary?

Most PCBs are green, however this color is not required, because this color of a PCB does not affect the performance or the device it powers but does affect the resolution and makes the solder mask harder to see on different colored boards. Other than green, red, blue, black, and white are commonly used. All colors of the rainbow can, however, be found on some circuit boards.

Colors are frequently linked to distinct sections of a device. Most computers, for example, have green motherboards, which assist technicians in identifying the core PCB. Other boards are used for lesser activities and may be color coded to indicate their functions.

Get Free Quote for Your Customized PCB

However, non-green circuit boards can be difficult to work with. For example, the black ones overheat under pressure, whilst the white ones stay unreadable. For this reason, red appears to operate better due to its high color contrast, whereas blue is recommended for visual comfort.

Finally, while green PCBs remain the standard for historical, practical, and budgetary reasons, all other hues are available because manufacturers provide their devices in colors that meet specific demands or are fashionable.