Generally, a distinction is made between the natural hair colors blond, red, black and brunette. People with a dark complexion usually also have dark hair, while people with a rather light and pale complexion usually have blond hair.
All hair colors that differ greatly from blonde, red, black and brown are not considered natural colors that nature intended for humans. However, if you want to dye your hair, you have an almost unlimited choice of colors. The colour palette ranges from mahogany and auburn to copper blonde and classic grey, leaving no wish unfulfilled.

Professional hair colors are often marked with numbers or a combination of numbers and letters. The following applies here:
Number / Number
Criterion
Explanation
Number before the slash (or comma or period)
The color depth
The higher the number, the lighter the tone (1/ = black, 12/ = platinum blonde).
first number after the slash
the color direction
Represents the main tone or main color reflex. Also refers to whether the resulting color has a warm or cool hue.
second number after the slash
the gloss
Determines the secondary tone or the secondary colour reflex, i.e. the reflections of the colour. This is less visible and usually corresponds to the main tone.

The type of product you choose depends on your desired target hair color. There is usually a distinction between tinting, intensive tinting and permanent colouring.
I recommend a tint (durability level 1) if you want to refresh your hair colour and give it more shine. The color does not penetrate into the hair structure, but lays purely externally on your hair, making a tint the gentlest technique. However, you can't change your hair greatly or lighten it by tinting. Also, tints do not cover gray hair. On the positive side, there is no annoying build-up, as the tint washes out after about eight to ten washes.
In contrast to a normal tint, an intensive tint (durability level 2) contains chemical ingredients. This makes it more durable and lasts for about 28 washes. With an intensive tint, your hair is artificially pigmented, so you can even lighten your hair by one shade. However, if you are a brunette and want to go blonde, you will need a bleach or permanent hair colour.
Permanent hair colour, also called colouration (durability level 3), is suitable for extreme colour changes or to cover white or grey hair. The colour penetrates deep into the hair and cannot be washed out as with tints, but remains for a longer period of time.

Which hair color suits you depends a lot on the color type. There are four different colour types: Spring, summer, autumn and winter type. The main distinction is whether your skin has a warm or cool undertone. If your face appears slightly bluish, it has a cool tone (summer and winter). If your skin has a yellowish glow, it has a warm complexion (spring and autumn).
You can find various websites online where you can get colour advice. Hair specialists will help you find your perfect hair colour depending on your personality, your preferences, current hair colour trends, the season and other aspects.

If you have short, medium or shoulder-length hair, one pack of hair colour is usually enough. For long hair, it is better to take two packs to be on the safe side. In any case, read the product information carefully to determine the yield of the color.
The product and the manufacturer are crucial, as the amount of colour you get in a pack can vary. It also depends on how thick your hair is. With very full hair you definitely need more colour than with thinning hair. It also depends on the consistency of the colour. You can often only find out how well it spreads by trying it out.

While the exact process of mixing depends on the product, there are general instructions you should follow:
Type of paint
Mixing instruction
Semi-permanent colors
ready for use
mixing of the shades with each other is possible, as long as the process is not oxidative
Permanent colors
not ready for use
mix with hydrogen peroxide before use
Vegetable colours (henna etc.)
mix with hot water
you get a paste that spreads well in your hair
you can add different contents to henna to change colour reflexes (walnut, red wine or tea)
Oxidative colors are mixed with hydrogen peroxide. Usually you use equal parts of peroxide and colouring cream. You should mix the chemicals in a non-metallic bowl, as metals can react unfavourably with the hydrogen peroxide. It is best to mix the components with a plastic paint brush. When you mix hydrogen peroxide and an alkali (usually ammonia), an oxidation process begins immediately. This process has a limited reaction time, so you should apply the mixed paints quickly.

That depends on various criteria. It depends mainly on the condition of your hair, the product, the application and care. Some products last several weeks in your hair, others even for months. You decide when it's time for a new color application. With these tricks your hair colour will last longer:
Don't shampoo until 24 hours after coloring.
wash less
use the right shampoo (colour shampoo)
only shampoo the roots (the tips are washed when rinsing)
intensify the color with Color Conditioner
Seal the colour with conditioner
use heat protection when styling (heat can bleach your hair)
Use sunscreen spray on your hair (UV rays can fade it)
Either grow out dyed areas or over-dye them. Renew your color only after some time, it can fade and look dull in the meantime. You'll know when it's time for a new splash of colour.

With many permanent hair dyes, there is usually no risk of serious harm, since especially products from renowned manufacturers have to pass elaborate approval procedures.
However, hair dyes are not entirely harmless. A large number of them contain chemicals, some of which can trigger allergic reactions up to and including anaphylactic shock. Among the substances that particularly often trigger allergies are:
Toluene-2,5-diamine sulfates
paraphenylenediamine (PPD)
Resorcinol
Ammonia, which is used in many hair dyes to dissolve the protective cuticle layer of the hair so that the color pigments can penetrate better, also makes the scalp more permeable to harmful substances.
Generally speaking, the less contact the hair dye has with the skin, the lower the risk of allergies. Therefore, you should always wear gloves when self-dyeing and give your hair a break so that it can regenerate.

Yes, you can find some natural hair dyes without chemicals on the market. The most commonly used plant dye is henna. Henna has been used for thousands of years to color skin and hair.
Due to modern product development, vegetable dyes are now available for blonde, red, brown and black, which are getting better at covering gray hair. However, the application of vegetable hair dyes is much more involved than mixing a chemical hair dye.
Caution: Although products advertise with terms such as "Henna", "Organic", "Natural" or "Bio", some non-certified products still often contain questionable or even banned substances, even if the product name suggests otherwise.

To remove color from your hair faster, a hair scrub or oil treatment will help. You can make a natural hair scrub from coffee powder, sugar or baking soda. Mix equal parts of the ingredients with water to make a paste and then spread it through damp hair.
If hair colour gets on your hands or face, you can remove it with baking soda. To do this, mix two teaspoons each of baking soda and a mild dishwashing detergent with a little lemon juice, wet a washcloth well and dip it into the paste. Rub the mixture onto the discoloured skin in a circular motion, slowly scrubbing the stain away. Finally, rinse with lukewarm water.
If the stain is not too stubborn, you can also try using liquid dishwashing detergent alone as a hair colour remover. In general, remove hair color from your skin as soon as possible, because the longer you wait, the harder it is to remove. In the end, take good care of your skin with, for example, a mild toner and a soothing cream.