Bleak browns, blues and greys infuse daily life - the flowered patterns are cheap, old and autumnal, but they suggest the possibility of hope. Iris' pink headband tying back her greasy hair is an assertive note, perhaps an expression of her strength and individuality.
Iris meets a man. The pink that was confined to her hairband finds full expression in the dress she buys for her date - colour enters her life.
The protagonist's bleak life is turned around when she falls pregnant after the one-night stand. There is the possibility of a new life, and she prepares to meet her lover to tell him the news. He brutally rejects her. Note the baby-clothes colours and bottle of pop with a straw, and how the change in her hair subtly suggests her feelings.
Here is the compelling opening scene of a match factory production line:
There's an excellent article on Kaurismaki on the Senses of Cinema website here.