Shade Variations of Black & Gray for LSR Pigments

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Apple Rubber has meticulously designed silicone parts and seals for a wide array of industries, including medical, automotive, aerospace, and electronics. From basic seals to the most intricate silicone parts, we employ a range of sophisticated technologies and processes in order to consistently produce the high-quality silicone components your applications require. Over the years, we’ve become known for our ability to provide our customers with both standard and custom pigments for Liquid Silicone Rubber (LSR), including a surprising variety of shades of black and gray. 

LSR is an extraordinary manufactured material. By combining the appropriate additives in the correct amounts, silicone is transformed into highly specific material. Here are some of LSR’s attributes:

  • Durometers ranging from 10 to 80 Shore A
  • Ability to withstand freezing temperatures and high heat, from -65°C to 200°C.
  • Translucent or pigmented to match any color 
  • Resistant to fungus 
  • Non-toxic

In their natural form, liquid silicone elastomers are usually clear to opaque white. A small quantity of pigment, usually 2-3%, can be added to attain the desired color with little to no effect on physical properties. During the initial mixing of LSR and Pigment many grays and black look the same.  It is not until after the LSR is cured and post cured does the color difference become noticeable. 

At Apple Rubber, we have various color options available to meet your company’s wants and needs. For example, 8 black and 10 gray options are distinguished based on a series of numbers or letters. So, how can you determine which number/letter series paste is suitable for you? Using a Capsure color meter, a pocket-sized color identification tool, we put our colored paste to the test to determine a specific paste color using the universal language of color, the Pantone color system. 


Using a constant compound, LSR 2070, a 70 LSR clear, test slabs with 2% color were formed using 8 of our available black pastes and 10 of our available gray pastes. The paste color was measured using the Capsure color meter to gauge just how different our colored pastes are. Below in Tables 1 and 2 is our paste color identification description, followed by the identified color image and description, and the sRGB values (the standard RGB (red, green, blue) color space) for both paste black and gray. It can be observed that even though our paste black or gray is identified as ‘paste black’ or ‘paste gray’, we have a wide variety of options available to meet our customers’ desired product look. 

Table 1: Capsure Color Meter Readings for Paste Black (click to enlarge)


Table 2: Capsure Color Meter Readings for Paste Gray (click to enlarge)


Apple Rubber is happy to meet our customers’ unique requirements when making a custom product. Contact one of our engineers today to learn more about how we can help with your next project.