Pumpkin 1 has known her colours for a while, however, colour grading is still a little difficult. We have this colour box from IFIT. It has 4 shades of each colour and two of each shade so they can be used to grade colours or to match colours. You could also easily make your own version using paint samples.
So we’ve been working on light and dark. I pulled out a light shade and and dark shade of every colour and put them into a basket. The child then has to match the light and dark together. I thought it’d be really easy for 2 year olds but they actually find it a little of a challenge but not frustrating. 3 year olds like to do it too.