Frequently Asked Questions


Q. How much can a 10g (or 30g or 50g) pack of Yamato Indigo dye?

A. This is our most frequently asked question and it is challenging to answer precisely.

When you are wondering which pack to purchase, consider first how large the piece you would like to dye is. The 10g pack makes a 2 to 3 liter vat (size of a cooking bowl), 30g makes 6 to 10 liter (size of a water bucket), and 50g makes 10 to 17 liter. It is important that your piece can fit comfortably in the vat with enough room to "move around.”

The number of pieces you can dye largely depends on the type of fabric and its thickness, and how dark or light you want to dye.


A. How long do the vat lasts?

Q. If it is sealed well, the vat can last up to 1 week. Vat gets weakened by being exposed to the open air and becoming oxidized. When you are saving it for dyeing another day, make sure to seal the container well so the vat surface is not exposed to open air. Add soda ash (caustic soda) and sodium hydrosulfite to exhausted vat and it comes back strong.

You can also line your vat container with a plastic bag, make an indigo liquid inside the bag, then seal the bag when you are finished for the day. It also helps to make the vat in a tall bucket, rather than flat container to minimize the surface exposure to the air.


Q. How can I achieve dark indigo color?

A. There are a few techniques to dye dark color.

First, make sure to rinse your fabric very well in water. If possible, use warm or hot water. If your piece is canvas, boil it in hot water. Fabrics, especially when brand-new, often have all sorts of coating on the yarn. Rinsing items off before dyeing can help achieve better results.

Make a large and rich vat. 5g of Yamato Indigo per 1 liter of water is ideal.

Make sure to keep massaging the fabric when you are dyeing it in the vat. Leave it exposed to the air for oxidizing well. Instead of dipping for 20 minutes and oxidizing for 20 minutes, dip for 5, oxidize for 5 and repeat the process 4 times or more. 

Vat is strongest when it is just made, and gets weaker (less pigments left in the vat) as you use them. Dye thick/large items first, and move to smaller/thinner items. When your vat is exhausted, add soda ash (caustic soda) and sodium hydrosulfite. The vat comes back very strongly, even stronger than when it was fresh. This is also a good opportunity to dye large/thick items in dark.

Note: Do not add soda ash (caustic soda) or sodium hydrosulfite to a fresh vat. They will not make a fresh vat stronger, it only works with weakened/exhausted vat.

If your fabric still doesn’t take the dye well and color is light, it may not be a 100% natural textile and contains synthetic yarns.


Q. What is good to dye with Yamato Indigo?

A. Indigo in general dyes plant-based textile well, such as cotton, linen, or ramie. Yamato Indigo also dyes silk well.

Used, vintage textile dyes better than brand-new, never-worn or washed textile. Yarns of used textiles are “beaten-up” and take dye well. Yarns of brand-new fabrics often have coating. Make sure to rinse them well in water before dyeing.

Yamato Indigo doesn’t dye synthetic fabric. Most contemporary garments are sewn with nylon thread, so seams often remain undyed/white.


Q. Can Yamato Indigo dye wool?

A. Yes. However, the process is much more complicated than dyeing cotton or silk and requires additional agents. We hope to start selling the agents for wool dye soon.


Q. What does Yamato Indigo consist of? 

A. Yamato Indigo consists of extracts from indigo plants (natural indigo), chemical indigo, alkaline agent, and reducing agent. 


Q. Is Yamato Indigo natural?

A. No. It does contain natural indigo (pigments extracted from plants) but it also contains synthetic indigo and agents.


Q. Does the dye come off or rub off? 

A. Yes. This is a characteristic of almost any indigo dyed fabric. After dyeing, make sure to rinse your garment well, as the indigo may still come off or rub off on other white garments. Avoid washing with whites.