Some manufacturer includes color notations in their charts or technical documentation. That color notation defines the color much more accurately than a color name.
Two systems used most frequently to describe colors (by artist paint manufacturers) are Munsell notation, and CIE L*a*b. You can read about those on Handprint or check the links on the Colour Online by David Briggs.
On this page, I mainly use this data to provide an easier navigation:
- Munsell Navigator
- HLC Atlas Navigator
- a*b* planes for paint brands
- Traditional Color Wheel (coming soon)
- Searching for similar hues
3105 paints has some kind of color notation (in total there are 28303 paints in the database).
Whenever those notations from are available, I display them next to the paint. Sources for color notations (in this order):
Published by the manufacturer. Some manufacturer (for example Golden) provides also details about how those measurements are done.
My own measurements. Disclaimer: I don't have access to a high-end colorimeter or spectrophotometer, so those numbers are not up to any scientific or industrial standards. I'll give a more detailed description about my method later.
- Third party sources. Credits are displayed next to the source.
CIE L*a*b, HLC, RGB, and Munsell values are displayed. Depending on the source, I use the following methods to calculate / interpolate.
- Lab → XYZ → RGB, Lab → HLC : I use the algorithm, based on the information from EasyRGB (for RGB, i note if it's out of gammut)
- Munsell → Lab: for the interpolation I use the munsellinterpol R package
When displaying a paint in the Munsell or HLC Atlas Navigator, I assign the color to the nearest spot on the navigator. To calculate color distance, I use CIE ΔE 2000 formula.
For example Munsell 1.5Y 8/13: 1.5Y is a special intermediate hue which is not in the navigator, so it links to 2.5Y 8/12 which is a close, but fairly distinct hue.
The data sources for the color navigators are:
- HLC Color Atlas by freieFarbe e.V. (Creative Commons license CC-BY-ND 4.0)
- Munsell Renotation Data: Munsell Color Science Lab Educational Resources / RIT
As I mentioned earlier, my own measurements are not up to any scientific or industrial standards.
I use a simple NCS Colourpin Pro. It comes with a ceramic calibration tile, has a fair repeatability, and worked good enough when I tested against ColorChecker tiles. For the current purpose (make it easier to navigate through paints, and show similar colors) is good enough.
I try to follow a repeatable workflow: for watercolor swatches I measure masstone. It's not always easy to do that consistently with a watercolor swatch, in some cases I calculate an average of multiple measurements.
Finding the masstone for gouaches / acrylic swatches is much more straightforward, so I prioritize gouache / acrylic swatches over watercolor one when both available.