Green has traditionally been considered the standard colour for PCBs. However, with advancements in technology and creativity, the range of available PCB colours has expanded significantly.

Every assembled circuit is built on a printed circuit board (PCB). The PCB is the core component and the foundation of modern electronics.

This topic is often overlooked, yet understanding the basics of PCB colour is crucial.

Wellcircuits offers a wide range of colours to enhance your design.

Understanding the basics of PCB boards and solder mask colours will be much easier with the help of this guide.

The colour of the solder mask is typically influenced by the colour of the PCB itself. The solder mask, made from coloured lacquer, is designed to conceal the copper traces beneath. The final colour of the PCB, which is made from glass and epoxy, reflects the solder mask. One of its primary functions is to protect the circuit board from short circuits.

PCBs are available in a variety of colours. While green has been the traditional colour for PCBs, the growing range of available colours is driven by technological advances and innovation. Recently, many manufacturers have been shifting to non-green PCBs, moving away from the conventional green hue.

Here are some reasons why you might choose PCBs in colours other than green:

• Different PCB colours can help identify revision changes, alerting users to important updates.
• Choosing colours other than green can make the design appear more vibrant or compact. It’s essential to consider how the assembly equipment’s light transmission, absorption, and reflectance properties affect the design.
• Distinct colours can help avoid mistakes in complex assemblies. Additionally, they can assist in easily identifying lead-free components during assembly.

Here is an example of a wellcircuits ruler. Wellcircuits offers a total of 9 different solder mask colours.

White, blue, black, yellow, red, and other colours are among the options for PCBs. These are often referred to as PCB colour codes. Modern PCBs come in many different colours and styles. For example, green epoxy is still commonly used for manufacturing PC motherboards.

The performance of the PCB is not affected by the colour of the solder mask. However, the resolution of the board may vary depending on the colour used. For instance, red and blue solder masks tend to have lower resolution than yellow or black. It’s worth noting that solder masks with clear transparency usually offer the highest resolution.

Introduction – Solder Mask

Various solder mask colours are available. A black solder mask, made from cobalt and carbon, is conductive due to the carbon content. While conductive layers are formed over the PCB’s traces, this solder mask helps shield the signals from external interference.

A black solder mask made from cobalt alloy is also more expensive. White PCB colours are commonly seen in LED applications, while blue solder masks are typically used in LCD displays to reduce system distractions.

Red PCBs are often used to distinguish one board from another. The red solder mask is typically used in precision equipment like oscilloscopes, analog meters, and bench multimeters to identify specific parts in an assembly.

It is widely acknowledged that green is the most commonly used colour for PCBs. The popularity of green is attributed to its superior performance in soldering component pitches. Green has long been considered the standard for PCBs.

Japan, known for its cutting-edge technology and innovation, leads in the use of green PCBs. On the other hand, Germany has been more experimental, frequently using non-standard PCB colours in various engineering sectors.

PCB Solder Mask Color Options Available – Wellcircuits

When choosing printed circuit boards, there are several factors to consider, including the colour of the solder mask. While green remains the most common colour, alternatives like yellow, white, and black are also available at no additional cost. The challenge is deciding which colour to choose, given the variety of options. Does using colours other than green have any pros or cons? The following brief guide can help you choose the right solder mask colour:

Red solder masks typically have a bold, professional appearance with excellent contrast between planes, spaces, and traces.

However, the contrast with a red PCB is less distinct than with a green PCB. Traces on a red PCB may require higher magnification to inspect. It’s important to note that red backgrounds can resist flux residue removal, making cleaning more challenging. Despite these challenges, green remains the preferred option for most applications.

Blue: The blue solder mask colour is often associated with Arduino projects. While the contrast between planes, traces, and spaces is lower than with green or red PCBs, magnification is necessary for inspecting manufacturing defects.

One advantage of the blue solder mask is its strong contrast with the silkscreen layer. If your design includes heavy components, blue might be the optimal choice.

Blue is also a good option if you want to match the solder mask with your Arduino design and don’t mind less visibility for off-board traces.

Black: Black PCBs are challenging to work with. The contrast between planes, traces, and open areas is minimal, making inspection difficult. Strong magnification and a specific angle are required to spot traces.

Another issue with black PCBs is their tendency to absorb heat during reflow soldering. Cleaning black solder masks is also more difficult, as flux stains are harder to remove and may require additional steps.

A benefit of using black is its contrast with the silkscreen layer. The separation between silkscreen and pads is usually quite clear without additional lighting or optics. Currently, only gloss black is available; matte black solder masks are not yet offered for PCB prototypes.

White: White solder masks are often considered the most difficult to handle. The contrast in white PCBs is much lower compared to black or green, and turning the board to different angles does little to improve trace visibility. White PCBs are particularly challenging to clean due to the difficulty in spotting traces.

Although the contrast with the silkscreen layer is similar to black, the overall visibility issues make white solder masks less practical. Therefore, we generally recommend against using white solder masks in most cases.

Yellow: Despite its vibrant appearance, yellow is rarely chosen by designers and engineers. The contrast between traces, voids, and planes is excellent, especially when compared to green. Yellow solder masks can be a great choice if your PCB design is well-routed and aesthetically pleasing.

Yellow solder masks pair well with black silkscreen, offering better contrast than white. This combination can provide excellent results for your design, with no significant cleaning issues. Considering its superior performance, yellow should be considered alongside green and red when selecting PCB colours.

That concludes our overview of various solder mask colours. With this guidance, you should feel more confident in selecting the right colour for your next project.

Explore new solder mask colours like PINK, ORANGE, GRAY, and even TRANSPARENT at Wellcircuits!

Author: Stack Thomas

If you have any questions about PCBs or PCBA, please feel free to contact me at info@wellcircuits.com.