Semi-permanent vegetable dyes, such as henna, are a good choice, but study the label - some products billed as 'natural' also contain strong chemical dyes.

Its decline came when chemical dyes were discovered.

The dyeing industry has decayed with the introduction of chemical dyes.

Using locals technical knowledge of chemical dyes, the industry grew bigger than ever at the turn of the 20th century.

But the invention of chemical dyes put the indigo industry out of the business scene.

The gel has molecules that bind to bacteria and activate a fluorescent dye.

Probe molecules, typically labeled with a fluorescent dye, are added to the array.

The maleimide functionality allows conjugation of the fluorescent dye to the sulfhydryl group of cysteine residues.

A similar redox-based assay has also been developed using the fluorescent dye, resazurin.

Assuming a pure fluorescent dye solution in an isotropic surrounding, the individual emitters are indistinguishable.

Add 1½tsp of the orange juice and a few drops of red and yellow food dye.

I would then absolve them by sprinkling them with holy water (tap water with blue food dye in it).

Then simply splatter it with pink food dye.

Colour lemonade with red food dye for blood or orange as pumpkin juice.

Fill a rubber glove with water and food dye, freeze and take off the glove for a scary sculpture.

Hair dye firms urge people to do a skin allergy test before using the product.

Doctors told her she had some of the worst burns they had seen linked to hair dye.

Then after a quick change, some hair dye and a kip, she re-emerged with a pair of bunnies, inset.

Gone were the smart clothes, the hair dye and make-up.

She would like her story to be a stark warning to people buying home hair dye kits.

This permanent dye comes in a variety of shades and offers a good depth of colour.

Permanent dye takes between 48 and 72 hours to fix itself into the hair cuticles and, after that, it may well not budge at all.

If you are covering greys, choose permanent dye for full coverage.

A one-color permanent dye creates a flat, uniform color across the whole head, which can look unnatural and harsh, especially in a fair shade.

Aside from henna, more common permanent dyes were based on natural substances and perhaps more unorthodox mixtures.

This research on naphthalene gave much impetus to the synthetic dye industry.

Fuchsine was another synthetic dye made shortly after mauveine.

Mauve became a popular fashion color after the invention of the synthetic dye in 1856.

Most other classes of synthetic dye, other than vat and surface dyes, are also applied in this way.

He scaled up production of the new mauveine, and commercialized it as the world's first synthetic dye.

It can be used as a vegetable dye to dye leather red.

The parade committee has since switched to a mix involving forty pounds of powdered vegetable dye.

Semi-permanent vegetable dyes, such as henna, are a good choice, but study the label - some products billed as 'natural' also contain strong chemical dyes.

Vegetable dyes will leave your hair super-glossy, and are partially chemical-free.

Most of the products used are based on vegetable dyes or plant extracts and usually wear off without causing any long-term damage to the plant.