Chris Li is former Product Design Lead at Amazon who led the design of multiple generations of the Amazon Kindle.
After many years at Amazon, I joined PillDrill as the 5th employee to shepherd our health-tech product from concept to production. The team decided on bright teal as our brand color, which we splashed onto our slick teaser website. This teal and five complementary tones looked great on screen, so our industrial designer liberally used them to craft beautiful digital renderings.
But when the time came to turn those renderings into a real product, we ran into trouble matching our system's different components and substrates to the bright hues the team had selected. When I should have been focused on buttoning up our final production processes, I found myself learning about color the hard way, poring over different part samples chasing that elusive perfect shade of teal.
Background on Color
Digital screens like your cell phone or computer monitor display images encoded in RGB - or combinations of Red, Green, and Blue light. If you look through a microscope at a typical LCD you can spot the Red, Green, and Blue sub-pixels. RGB is an additive color model which starts from black with the subpixels being all off (0,0,0 in RGB) to white with each subpixel being fully illuminated (255,255,255 in RGB).
Figure 1: CMYK vs RGB color representations. Credit to: Steve Caplin at creativepro.com/understanding-difference-between-rgb-cmyk/
Contrast this with most printed products like office documents or packaging using a subtractive AKA reflective color space like CMYK. Cyan, Magenta, Yellow, and Black component colors are overlayed on a white background. We perceive the colors only when light is reflected off the colored surface.
But even with these two basic models of color, much of what we see in the real world depends on the individual display or the paper and ink used.
3 Factors to Consider for Color Matching in Hardware
The teal in the PillDrill product was designed into everything from the soft-touch painted main housing, bare plastic container lids, a rubberized TPU strap, silk-screened plastic sheets, and pad-printed logos, not to mention the different uses in the packaging and our digital companion app! After days spent at different factories in China, I learned about the following key aspects of color in manufacturing.
Materials, Processes, and Finishes
Metals, plastics, and paints have their own inherent color characteristics. Different alloys and additives also influence their final coloration. High-heat and pressure processes like injection molding, casting, or forging can change material properties and affect color. Different surface treatments, such as brushing or mirror-polishing, influence the gloss levels of a part. Secondary treatments like paint can cover a surface, while anodization or PVD tint the surface while retaining the base material look.
If your product has a mix of several of these surfaces, make sure you see what the components all look like together before signing off on any one part. Any imbalance can throw off your capacity to match color entirely.
Light Sources and Color Matching
Typical daylight in North America has a color temperature of around 6500 kelvin; elsewhere in the world, it may be a warmer 5000k. If you’ve ever spent time on a factory floor in Asia, you know that most of them don’t have clear blue skies with ample sunlight to replicate a consumer environment. If your product is designed to be used indoors or at night, consider observing part samples at even lower temperatures like 4000k or 3000k. Have parts from the same batch sent to your local teams so they can review the colors in person under typical lighting.
Figure 3: Color temperature from warmer to cooler: Credit www.gadunky.com/colour_temperature_guide/
Measurement and Color Matching
When you produce a colored part, you need an accurate and consistent way to measure color. A D65 or D50 lightbox (65 stands for 6500k while 50 is 5000k) lets you view parts and products under reproducible lighting conditions. The CIELAB color space, sometimes referred to as L*a*b* or simply Lab measures three parameters of L* (lightness from black to white), a* (from green to red) and b* from (blue to yellow). Color meters can return measurements of L* a* and b* values and calculate a root sum square differential known as Delta E compared to a standard color reference. Delta E readings of < 1 are imperceptible to the human eye. Generally, < 1.5 is reasonably controllable and barely noticeable. If you want to measure the consistency of a high-gloss part, a gloss meter measures the amount of light reflected off the surface.
Tips for a smoother rollout
I recommend creating a plan to make sure the product colors are easily producible and measurable. Here's an example:
- Select initial colors from a curated, well-known color system like Pantone if you have limited resources or time. This is an accessible color standard that most vendors know. If color is important to your brand, ensure you have enough resources to follow through on all the work involved.
- Have your vendors create color chips in the materials and processes that you plan to use, making sure to understand the manufacturing tolerance limits for the additives, dyes, or finishes. Ask them to produce a range of colors or run their processes a few times to account for possible variation.
- Once a color is selected, make several sets of chips to provide to vendors throughout the supply chain. (Make extra, as color chips are notorious for disappearing or changing with time and use.)
- Measure those chips with a color meter and set variation limits for quality inspections throughout the supply chain.
- Run long-term reliability tests to understand how things might change in harsher use cases, under UV light for 72 hours in after contact with sunscreen, and set limits or adjust processes as needed.