..Is this normal on my orchid..

[Islander1]

I bought 2 orchids a few weeks ago. When inspecting them today I noticed one has got some black on the leaves but only on the underside nothing on top.

The orchid looks like it's in very good health. It has very lovely white flowers what have been there since I purchased it.

I have a few other orchid but have never seen this on any of them before. Is this anything to worry about? If so how can I stop it please.

[seasprout]

Looks fine to me, I have a couple of phalaenopsis With the same ‘blotches’, I think it’s just a reaction to real sunlight, as apposed to shop lights.

[Dead Dogs]

My orchids have all sorts of marks on their leaves. They are perfectly happy growing in the windows.
One is just is still in flower, having started to open its blooms towards the end of September.

Here’s a photo taken mid October.