A worksheet I created to exercise my students on the written form of colours. First they have to find the words in the wordsearch (they have to recognize a colour when they see it written). You can tell them to colour the word with its colour (e.g. if they find "RED", they should mark it with a red crayon).
The second exercise is a crossword puzzle. At this stage, they should remember the written word to be able to make the crosswords. If they are still insecure, they can always look at the exercise above to guide them.
The last exercise is only about telling the students' favourite colour. You can practice this orally first and then they must write it. They have two children to guide them in the answer.
I think this is a good way to exercise the written form of colours, because it's funny for them, they enjoy solving this kind of puzzles and so they become more motivated and learn better!
Colours included: blue, yellow, brown, orange, green, black, red, white, purple, pink and grey (both in the wordsearch and in the crossword puzzle).