Looking at depth of colour in the sky and sea

Have you ever noticed.  When you paint the SKY the darkest area is at the Top, the weakest is towards the bottom...that's because the sky recedes into the distance and that is seen as a weaker colour.

The opposite happens with the SEA.... that is Darkest in the distance.  (I remember this by thinking  the further you look out to sea, that's where the sea is at its deepest...hence the Darkest colour).  The foreground (nearest the viewer) is a weaker colour.

Does that makes sence???  well, yes I think it does....look at my illustration...

Do you get it?

Hope this helps.