February 09, 2020 5 min read

Natural Dye Glossary

Our hand dyed yarn and scarves are produced from the finest UK yarns and 100% natural dyes in our FelinFach Dye Studio. By sourcing pure botanical natural plant dye extracts for wool and fabrics, we are able to produce beautiful hand dyed yarn and scarves. The colours from natural dyes are enthralling, each will depend on where the dyestuff was grown, how it was harvested, the fibres being dyed, and the method of application we use.

It takes time, knowledge and patience but we love what we are able to do at the Dye Studio and hope that this comes through in the hand dyed yarn. Hand dyed colours, dyed with natural dyes may be repeated but they can never be exactly the same - part of the beauty of a handmade product!

Natural Dye Workshops

Learn or develop your skills in our FelinFach Dye Studio. Located in the north Pembrokeshire countryside, our hands-on natural dye workshops are held in a purpose designed Dye Studio. All the yarn and scarves for sale on this website have been hand dyed with natural dyes by the Tutor of these Workshops - Hand Dyed Yarn  - Hand Dyed Scarves.

Our workshops are led by an experienced tutor in hand dyeing with natural dyes. As featured in The Knitter, the article is in the series on Artisan Yarn makers and explores our processes for hand dyeing yarns with natural dyes and also our natural dyeing workshops. The Knitter comments, "Taking inspiration from the landscapes of the Pembrokeshire coastline, Karen Morgan of FelinFach produces gorgeous, natural hand-dyed yarns". It also states, "Our favourite yarns this month include beautiful hand-dyed treats and luxurious fibre blends" including the Hydref (Autumn) range by FelinFach". All our workshops are available in our Yarn Store.



Natural Dyeing Glossary

An aqueous solution where the pH of the solution is higher than 7 when measured with pH paper.

A general term for an ingredient that is not the dyestuff or the mordant, but is used to help change a colour or enhance softness, for example.

A term for the dyestuff or the colours the dyestuff contains

Colour shifting
How to change the colour of a dye by ph. It is also used for creating a darker shade by using iron.

The rub off of indigo or dye onto hands or clothes.

Dye Extract
A concentrated, powdered natural dye. The natural colour has been extracted, then purified, strained, dried and powdered.  Other natural dyes are used as whole leaves, shredded bark, sawdust, blossoms, berries.

Eco-dyeing or Eco-Printing
This is the common term for laying dyestuffs directly on prepared fabric, and rolling it into a bundle so that the dyes directly print onto the surface of the fabric. This is a low water use dye method.

Exhaust bath
In immersion dyeing, the dye is dissolved in a pot of water to create a dye bath and the fibres are put into the dye bath and are completely covered. When the fibre is finished, the remaining dye bath is called an exhaust bath and may be reused to dye additional fibres. This is a water and energy saving technique.

Indigo is considered a “layered” dye, meaning that it’s best the build the colour with several dips rather than to dip once.  Multiple dips are important to quality indigo dyeing and to reduce excessive dye rub off. Each dip allows more indigo to attach to the fibre, deepening the colour.

Light -Ffastness
The resistance of colour to fading. 

Mordanting prepares the fibres to bond with natural dyes and is typically a separate immersion bath for the fibres. It is important to submerge and agitate the fibres. Many natural dyes require the use of a mordant to achieve the most durable and long-lasting colours.

Over-reduced Vat
An over-reduced vat is when you have added too much reducing agent.  Add air into the vat with vigorous stirring to rebalance.  It’s common to over-reduce a vat if using an industrial reducing agent such as thiourea dioxide (thiol) or sodium hydrosulphite (hydros) but less common when using fructose or henna. 

A measure of acidity or alkalinity of water soluble substances (pH stands for ‘potential of Hydrogen’). A pH value is a number from 1 to 14, with 7 as the middle (neutral) point. Values below 7 indicate acidity which increases as the number decreases, 1 being the most acidic.

What this means for the natural dyer is that you can raise pH with basic ingredients such as soda ash, calcium hydroxide or other mild bases.  You can lower pH with cream of tartar, citric acid or vinegar. This allows you to have a greater range of colours as many dyestuffs create unique shades depending on the acidity or alkalinity of their dye baths.

Reducing agent
A chemical whose function is to remove excess oxygen from the indigo stock and vat. Without reduction, the indigo vat will not work properly.

A textile term for washing or cleaning fibres prior to mordanting and dyeing, often using a cleanser such as soda ash, or a soap, and near boiling water.

A continuous strand of yarn wrapped into a hank. Skein weights are based on the size of the yarn and the weight of the yarn. A typical skein’s weights is 100 grams or 4 ounces.

Tannins are substances of vegetable origin that include leaves, bark, roots, fruits and are typically astringent or bitter to taste. When combined with iron, they create a blue-black colour, and when used in mordanting cellulose fibres, they increase light-fastness and colour yield.

Under-reduced Vat
An under-reduced vat is blue.  If the vat is turning teal or blue-coloured, add more reducing agent and wait until the vat balances, clears and turns yellow-green or golden brown.  If it doesn’t balance within 30 minutes, check the ph. 

Vat vs Stock Solution
This is in reference to indigo. An indigo vat is the large container that you dip into. Indigo stock solution is the concentrated liquid that you create that is then stirred and put into the vat, then allowed to balance before beginning to dip.

Wash fastness
The resistance of dyed colour to washout when laundering.

Weight of fibre
The dry weight of whatever one is dyeing.

Natural Dye Colours

Cochineal insect (red)
Cow urine (Indian yellow)
Lac insect (red, violet)
Murex snail (purple)
Octopus/Cuttlefish (sepia brown)

    Plant-derived dyes

    Catechu or Cutch tree (brown)
    Gamboge tree resin (dark mustard yellow)
    Chestnut hulls (peach to brown)
    Himalayan rhubarb root (bronze, yellow)
    Indigofera leaves (blue)
    Kamala seed pods (yellow)
    Larkspur plant (yellow)
    Madder root (red, pink, orange)
    Mangosteen peel (green, brown, dark brown, purple, crimson)
    Myrobalan fruit (yellow, green, black, source of tannin)
    Pomegranate rind (yellow)
    Teak leaf (crimson to maroon)
    Weld herb (yellow)
    Juglans Nigra or Black Walnut hulls (brown, black, source of tannin)
    Rhus typhina or Staghorn Sumac tree (brown, source of tannin)

    About FelinFach

    Our company, FelinFach Natural Textiles is located in the heart of the Preseli area of Pembrokeshire near to Boncath. We design Welsh blankets and the iconic Welsh Tapestry blankets which are traditionally woven at Welsh mills. We also design and make natural hand dyed yarn, cotton, silk and wool scarves and other handmade products, all available in our yarn store and shop. We also offer Welsh tartansSheepskin Rugs, Gift Cards and tools and books for crafters and knitters - Cocoknits, Laine, Amirisu and Making to name a few! Lastly, craft courses on hand dyeing with 100% natural dyes in the purpose designed FelinFach Dye Studio. We are a proud supporter of the Campaign for Wool, All Things Wales and Global Welsh.

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    Last update 16th November 2021