CIE L*a*b*, HLC, and Munsell

Introduction

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).

Sources

Whenever those notations from are available, I display them next to the paint. Sources for color notations (in this order):

1. Published by the manufacturer. Some manufacturer (for example Golden) provides also details about how those measurements are done.
   Holbein Artists' Gouache (gouache)

   

   G571 Pure Blue

   CIE

   		RGB	r 0 g 100 b 171 #0064AB
   		CIE	L*	40.59	a*	-0.40	b*	-46.66
   		CIE	h°	269.51	L*	40.59	C*	46.66
   		HLC	H270_L040_C045
   		Munsell	3.5PB 4.0/11.5
   		Color	moderately dark valued, dull blue
   		Source	manufacturer

2. 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.
   Shinhan Professional Designers Gouache (gouache)

   

   017 Cadmium Yellow Orange

   CIE

   		RGB	r 253 g 111 b 35 #FD6F23
   		CIE	L*	63.55	a*	51.18	b*	63.43
   		CIE	h°	51.10	L*	63.55	C*	81.50
   		HLC	H050_L065_C080
   		Munsell	10.0R 6.0/16.0
   		Color	moderately light valued, intense orange-red
   		Source	gouache swatch masstone (D65 10°)

3. 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

Own measurements

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.

Brands with (manufacturer) Munsell notations

Brands with CIE L*a*b* information