You decide on a vibrant, bold paint colour for a room in your home. It looks perfect on the paint sample at the store and when the salesman shows you the paint before he seals it up, you enthusiastically say that yes, that is exactly what you want. Then, when you get home and start to paint that room, you instantly begin to wonder what in the world you were thinking. Bright orange? Don't fret. You can tone down and darken that orange paint, so you can enjoy your room with its new paint colour rather than have regrets.
Pour about a 1/2 cup of the orange paint into two plastic bowls. Have a tube or quart-size can of black paint and blue paint on hand. In general, you can darken paint with either black or the color's complementary colour. Blue is the complement of orange on the colour wheel.
Add 1 tbsp of black paint to one orange bowl of paint to make it darker. Mix well with a small paint brush. Add 1 tbsp of blue to the other orange bowl of paint and mix well with another paint brush.
Decide if you prefer the way the orange is darkening with the blue or with the black. Black will darken the shade of the orange. Blue, though, will darken it without changing the quality and value of the orange.
Continue to darken with either the orange and blue paint or the orange and black paint. Add more blue/black or orange to the plate until you have a sample of the colour orange you prefer. Keep track of the amount of paint you are adding.
Mix in the blue or black into the large can of orange paint you have, using the same ratio as in your sample. Vigorously mix with a paint stick as you go along. If you have more than one can of orange paint, pour the cans in to a 5-gallon bucket and add the blue/black in there since it will be near impossible to create more than one can of the same exact colour.
Pour some orange paint into a another container just in case you darken the paint too much. You can add it back in to lighten up.