Anodising is most often dyed using vegetable or sometimes aniline dyes then washed in boiling water to close up the pores, As Mete says the final process is usually a silicon based wax which closes in any open pores and provides a further protection. The type of anodising specifyies the depth of oxide which basically increases with the time in the electolytic acid bath, it is not just simply leaving it in longer, like most things there are other considerations.
But Anodised aluminum is durable and attractive used sensibly. Stailnless steels are passivated to speed up and enhance the formation of the oxide layer, particularly on cast martensitic steels where the iron is concentrated on the surface and so tends to rust, passivating removes this iron and leaves a chrome bearing layer which oxidises providing protection. Excluding the air from any of the stainless steels will cause it to corrode like ordinary steel, always makes me smile in the ads for stainless screws and bolts into wood and such " all rusting problems over" etc, only on the head you can see is reality.
