The color of PCB defines the color of the solder oil or solder mask. It consists of lacquer impregnated with pigments that are known for protecting the traces of bare copper. Made from glass – epoxy, the finishing color of PCB is representing the solder mask. One of the main applications of the solder mask is prevention against the short-circuiting of the circuit board.
Types of PCB colors:
There are different types of colors available for PCB boards. The standard color of printed circuit boards is the green solder mask. However, with the advent of much innovation and technological advancement, the color of PCBs is now changing. In recent years the use of other colors instead of green PCBs is on the increase was driven by most of the assemblers. The following are some reasons for choosing different colored PCB other than green:
•Using different colors of PCB gives an obvious indicator of the revision changes to make users aware.
•Using colors other than green will produce brightness or contract. You need to note that assembly equipment is significant by transmission properties, absorbance, and light reflectance.
•Using different colors will help prevent various types of mistakes in a mixed assembly that may occur. The choice of contrasting color types also has the advantage of identifying meetings that are lead–free.
The variety of colors used for fabricating PCBs includes white, blue, black, yellow, red, etc. The colors of PCBs are commonly referred to as PCB color codes. Different modern PCB types have adopted specific colors. For example, the motherboards of PC are still fabricated in green epoxy.
The colors of solder masks do not create any impact or effect on the performance of PCB. However, with the use of different PCB colors, the board resolution will be other. For example, green PCB resolution is matched using red and blue colors like the yellow and black color with significantly less resolution. It is to be noted that solder masks with clear transparency tend to have high resolution.
Solder mask colors:
It has been seen that there are different types of solder mask colors. Cobalt and carbon, when mixed, produce a black solder mask. This type of solder mask is conductive because of the presence of carbon. Conductive layers are formed across the traces of PCB, but it can be used as a protective shield for isolating the signals coming from different external noises.
Black solder mask made from cobalt mixture is expensive too. You will find white PCB color codes in most LED applications. You will see a blue solder mask generally used in LCDs. It is used to avoid any distraction caused within the system.
Red PCB color code is usually used for making the board look different from other boards. The primary purpose of using a red PCB color code is to identify any particular part present in group assembly. Red solder mask is typically used in precision devices, including an oscilloscope, analog resources, and bench multi-meter.
It has been seen from different resources that green is known as the most favorite color for printed circuit boards. It is because the performance of the green color is better as compared to other PCB colors. Green gives better results when it comes to the point of soldering the pitch of components. Green is often regarded as the default color being considered for printed circuit boards.
Japan is one of the top countries around the globe for innovation and engineering advanced technologies. It has been seen that the use of green printed circuit boards in Japan is on the highest percentage. In contrast, Germany has been reported to use non – standard PCB colors to a greater extent than many other countries and engineering industries.
PCB Solder Mask Color
If you are up for selecting the printed boards, some parameters require to be taken into consideration. One of them is choosing the color of the PCB solder mask. Though green is the most traditional color being used, other colors like yellow, white, and black, which are also available, do not require any extra charges. As there is a wide range of colors available for the PCB solder mask, the problem is which color needs to be selected. Are there any advantages or disadvantages to choosing any color other than green? Given below is the small guide which is going to help you in choosing different solder mask color other than the standard green color:
The red solder mask color tends to be bold and professional. The contrast present between planes, spaces, and traces is quite good.
On the contrary to the green printed circuit board, the contrast is lower. Any magnification is used for inspecting the board traces in case of defects. It is to be noted that silkscreen is known to stand against red background well as it cleans up the flux residues. Though red looks attractive, eye-catching and bold, green is still considered the best.
PCB color blue for the solder mask resembles the same Arduino blue color. Compared to red and green printed circuit boards, the contrast between empty spaces, planes, and traces is shallow. In blue solder mask color, magnification is considered necessary and is mandatory for inspecting manufacturing defects.
However, it is to be noted that the contrast between the solder mask and silkscreen is relatively high that is the plus point for using blue color. So, if you are using a board with the label – heavy, then the right choice, in this case, might be blue for you.
Remember that blue seems to be an excellent choice if you want to match the solder mask color with your Arduino, and you do not care about showing off-board traces.
THE Black PCB color is tough to handle. The contrast between empty spaces, planes, and traces is lower than other solder mask colors, but it is non – existent. Very powerful magnification is required for the inspection of this board. Inspecting it is nothing more than a nightmare as it needs a tilted angle for casting a shadow to find traces.
Another problem with black PCB color is its heat absorption during the process of reflow. As far as cleanliness is concerned, the black solder mask needs hard efforts because the flux stains tend to be harder on the board and eventually require steps to get removed.
One of the advantages of a black solder mask is that it works well with the contrast of silkscreen. The difference between silkscreen and pads is pretty much okay. You do not need any lighting or optics to see the distinction as it is visible. Currently, only gloss black is available. Matte black solder mask color is still to be designed for prototypes.
If you think that a black solder mask is the hardest to handle, you have not seen white yet. Experiments show that there is nothing good about a white solder mask. White PCB color exhibits contrast that is even lowest as compared to black. When it comes to inspecting, even tilting it to light does not help in its traces’ appearance. Cleaning the white printed circuit board is too hard as hints are hard to be seen. However, the silkscreen contrasts in white solder masks are the same as those found in black color, which implies that they work very well. Keeping in view other parameters, we don’t recommend the white solder mask.
It is to the surprise of why designers and engineers do not pick yellow PCB color. The contrast between empty spaces, traces, and planes is too high in the yellow solder mask. It is almost as same as green. So if you have some fantastic routing and your printed circuit board is some hard work of art, then this dark and coppery colored yellow solder mask is the right choice for you.
As the white silkscreen is not contrasting well, you can use a black silkscreen with a yellow solder mask. It has been seen that it will create excellent results for your design and work. Also, you will see that the yellow solder mask does not cause any problems with cleanliness. Yellow should be considered along with green and red colors, depending upon its outstanding performance parameters.