Some Colour Idioms in English:
1) BLACK OUT
- To darken by putting out or dimming electric lights.
- To lose consciousness.
Example:
During the war people in the cities were forced to black out their windows so that the enemy aircraft could not see them.
Suddenly the man blacked out during the parade and had to be helped to a quiet place.
2) TO APPEAR / HAPPEN OUT OF THE BLUE
- To arrive unexpectedly, usually after a long absence.
- To happen very suddenly and unexpectedly.
Example:
My brother suddenly appeared out of the blue yesterday. We hadn’t seen him for years.
I was driving home when out of the blue a deer jumped out in front of my car. I braked just in time to avoid it. We were both very lucky not to be hurt.
3) TO LOOK / FEEL BLUE
- To look / feel depressed or discontented.
Example:
Things are looking blue for Tom these days. His wife has left him.
4) GREEN THUMB
- A talent for gardening, ability to make things grow.
Example:
She has a green thumb and is able to grow one of the best gardens in our neighbourhood.
5) GOLDEN - a golden opportunity
- A great opportunity that might never come again.
Example:
This is a golden opportunity to make a business deal with that big company.
6) TICKLED PINK
- Be very pleased, thrilled, delighted.
Example:
She was tickled pink that you made the effort to go and visit her when you were in town.
7) TO BE IN THE RED
- To have an overdraft, to be in debt.
Example:
I am overdrawn again. I hate being in the red.
8) AS WHITE AS A SHEET
- In a state of great fear.
Example:
You look like you’ve just seen a ghost. Your face is as white as a sheet.
9) YELLOW-BELLIED
- Extremely timid, cowardly.
Example:
He is a yellow-bellied coward and never is willing to fight for what is right.
10) TO SEE SOMEONE IN HIS TRUE COLOURS
- To understand someone’s true character, often for the first time.
Example:
As soon as he made a fuss about returning her money, I saw him in his true colours.
Source: http://www.learn4good.com/languages/evrd_idioms/id-c.htm