"Describing Natural Dye Colours with HSV"

The Three Dimensions of Colour

Any colour can be precisely described by measuring it along three distinct axes. Albert H. Munsell, an artist and art teacher, developed a highly influential system based on this idea, comparing the description of a colour to describing a box by its length, breadth, and thickness. The Munsell system names these three dimensions Hue, Value, and Chroma. Another common model, HSV, uses Hue, Saturation, and Value. While the technical definitions vary slightly between systems, the core concepts are the same.

Let's begin by defining these three terms. We'll start with a straightforward article from Symfonie Yarns and then deepen our understanding with a more technical piece from the Munsell Color System.

To solidify these definitions with the precision that your design background merits, let's explore the more formal Munsell system's definitions. This system uses the term Chroma instead of Saturation. For our purposes, we can consider them largely interchangeable, with Chroma being the more technically specific term for colour strength or intensity.

This short video provides an excellent visual recap of these three concepts, which might help you synthesise the information from the readings.

Visualising the Colour Space

Thinking of colour in three dimensions can be made much easier with a visual model. The HSV (Hue, Saturation, Value) model is often represented as a cylinder, which is a very intuitive way to map these properties.

Using this model, every possible colour has a unique address in a three-dimensional space. This systematic approach is invaluable for a designer and educator.

Let's look at a beautiful, practical example from the world of natural dyes.

Take a moment to analyse this wheel using our new vocabulary.

• The hues change as you move around the circle: yellows and greens in Spring, vibrant magentas in Summer, earthy oranges and reds in Fall, and deeper purples and browns in Winter.
• The value changes as you move from the outer ring to the inner ring. The outermost colours are generally the lightest (highest value), while the colours become progressively darker (lower value) towards the centre.
• Saturation also varies. The bright, clear yellows of Spring have high saturation, while the muted, earthy colours of Fall and Winter often have lower saturation.

Applying the Vocabulary to Dyeing Results

Now, let's bridge the gap between theory and your dyeing practice. How can you use this vocabulary to describe the results you get from different dyes, mordants, and modifiers?

The best way to learn this is to listen to an experienced dyer describe their results and then translate their intuitive language into the formal terms of Hue, Saturation, and Value. The following video tests different mordanting methods on cotton and provides a perfect opportunity to practice this.

Let's break down what you just saw, applying our new framework.

• Madder Root: The dyer describes the control sample (no mordant) as "pretty saturated actually but it's kind of brown." In our terms, this is a red-orange hue with relatively low saturation and medium-low value. She calls the aluminum acetate sample the "most vibrant color... a bright orange red," indicating a similar hue but much higher saturation and a higher value. The aluminum lactate is a "more lipsticky color... even more of like a it might even be richer." This suggests a subtle shift in hue towards blue-red, with very high saturation and a slightly lower value than the aluminum acetate sample.

• Osage Orange: She calls the control "very dull," which is a perfect description of low saturation. The mordanted samples are "more vibrant," meaning they have higher saturation. When she notes that after sun exposure "none of them look bright yellow," she is observing a loss of both saturation (they become duller) and value (they become darker/muddier).

• Avocado: Here, hue is the main story. She's looking for a pink or red-purple hue. The control is a good starting point. The alum and sodium acetate sample is "very brown," a significant shift in hue to orange-brown with low saturation. After sun exposure, she notes that several samples "didn't really stay pink," describing a loss of the desired hue.

• Logwood: This shows the most dramatic shifts. The control sample is a brown hue with low saturation. The successful mordants, however, produce a "delish blue color" — a complete change in hue to blue/purple with high saturation.

By using Hue, Saturation, and Value, you can move from subjective descriptions like "nice" or "funny colour" to objective, repeatable observations. This is the language you will use to build your colour sample books, to explain choices to your workshop participants, and to document your own creative process.

Conclusion

In this lesson, we have established a precise and professional vocabulary for describing colour. This framework is not just academic; it is a practical tool for any serious designer or dyer.

Here are your key takeaways:

• Three Dimensions: All colours can be described by their Hue (the colour's name, e.g., red), Value (its lightness or darkness), and Saturation/Chroma (its intensity or purity).
• Systematic Description: Using this vocabulary allows you to move beyond subjective impressions to make objective, communicable statements about your dye results.
• Analysis of Variables: This framework is essential for analysing the effects of different variables in your dyeing process—how a specific mordant affects saturation, how an iron modifier lowers value, or how a pH shift changes a hue entirely.

You are now equipped not only to create a wide range of colours but also to describe them with clarity and precision. In our next lesson, we will combine these skills. You will learn to predict colour shifts resulting from different mordant-dye-fibre combinations, turning your knowledge into a powerful creative and pedagogical tool.