Warm
Warm toned people have Golden, Olive, or dark skin with Brown or dark eyes. Their hair is Black, Brown, Blonde, Red, or Strawberry blonde. People considered warm tan easily. If you are warm toned, your hair reflects Gold, and Gold jewelry looks good on your skin.
Cool
Cool toned people have fair skin with blue or green eyes. They have blonde, black, or brown hair. If you are cool toned, your hair might reflect silver in the light. Silver jewelry looks good on cool skin tones.
The paper & veins test
Turn your arm over. Look at the veins in your wrist and forearms. If they appear to be Green, you have warm tones. If they are Blue, you are cool toned. Another method is to hold a White piece of paper up to your face. If you are cool toned, your skin will look Blue compared to the paper. If you are warm toned, your skin will look Yellow or Golden next to the paper.
Undertones that suit cool & warm
Warm shades are Honey, Golden, Butter, Caramel, or Copper. Cool shades are typically Ash, Beige, and Ice.
What to go for
Adding warmth to your hair if you have Pinkish hues in your skin can result in an over-reddening of your face. Go for cooler blonde shades, like Sandy blonde, Ash blonde, or Beige blond. Go for a darker, Honey blonde if you have darker toned skin.
Darker and Olive toned skin may not be right for a really bright blonde shade, try a Honey blonde instead. Another suggestion is to keep your darker roots and ask for golden Beige highlights. The roots help prevent your face from washing out. Caramel is another shade of blonde that will compliment your tones. Alternately, you can try buttery or strawberry blonde shades.
If you have Brown hair, be careful going too light because it can wash you out. Avoid platinum, white, or orange. Go for blonde highlights instead. Also, if you have warm skin tones, avoid brassy blonde colours. Brassy blonde colours can end up giving you an Orange hue. Ash colours can leave you washed out
Go for Gold tones when you have fair skin. If you have light skin, you want to choose Gold, Strawberry, or light blonde while staying away from White, Ash, and Red undertones. The lighter your skin, the lighter the shade of blonde you can go while still looking natural.
Should I go blonde?
Colouring your hair blonde works well if you were blonde as a child, or your hair becomes more blonde as you spent time in the sun. Ultimately though, Anyone can go blonde, but you have to find the right shade for your skin.
What’s the best strategy?
It’s wise to consult a colour specialist for drastic changes. Drastic would be a blonde that goes beyond 2-3 shades lighter than your natural hair colour. Extreme blonde shades or highlights often require multiple lightenings, and often, multiple visits to the salon. If you try to bleach your hair at home, you could end up with banana or canary Yellow, Orange. Anyone can get Platinum, but it may take months to achieve.
Obviously it will be much easier to reach White blonde with a lighter base to start with and hair that has been coloured before or that is naturally dark hair will take much longer. To safely colour your hair while maintaining its condition, you need to gradually lighten. If your hair is dark, you probably are not going to be able to reach Platinum in one visit. It could take months of colour applications of gradually lighter shades to work you up to a White blonde.