If red poster colour becomes too pale after adding white what correction can be made?

Correct answer: Add a little base red back

The governing concept is tint correction: adding white to red produces a lighter tint, but too much white weakens the original hue and makes it look pale. The correct remedy is to add a small amount of the original red gradually, mixing and checking after each addition until the desired strength returns. More white would make the tint paler, green could dull or neutralise the red, and a lot of black would create a dark, muddy shade rather than restore the red.