I'm still fairly new to all this (only got 3 paintings under my belt), and I've just tried doing a fourth today that has resulted in a number of frustrations (mostly because I don't know why what's happening is happening).

I tried painting Winter Mist this afternoon as it seemed a fairly simple (to my mind) painting to attempt, and I wanted to try a snowy painting. These are the problems I ran into

Colour

In Bob's video, he says he made the grey for the sky using the Van Dyke Brown, Prussian Blue and White, but every time I tried this, with varying amounts of the different paints, I ended up with basically blue. I even tried just putting in the smallest amount of blue, and still I ended up with a blue colour

These are my attempts on the palette

At no point did any of them look grey. In the end I went for a little midnight black and white to try and get a grey (and even that I would argue resembled purple more than grey.

The next issue I had with colours was when it came to the first set of mountains, that for reasons unknown to me, they ended up green. I did what Bob said, and used brown and blue.

Nothing I could seemed to make a difference. I even tried just putting straight Van Dyke Brown on the mountains, but as soon as I put some white on, the colours all went off again.

So in Bob style, I tried to treat this as a happy accident, maybe I can just cover how green they were with clouds, which brings me onto my next issue.

Clouds

I cannot get them to work. This is the third time I've tried them now, and they don't do anything remotely like Bob gets. For a start, I can load the fan brush full of white, but almost the second I start doing my little circles, that white is basically white + sky colour and I end up with zero definition in my clouds. In one of my paintings, I thought this might be because I used too much paint in my sky, but I really tried reducing how much paint I used for the sky in the next painting, and I ended up with the same thing. The problem I then get is, when I go to top the brush up again, I'm no longer getting white on my brush, because the colours are all mixing again.

The other thing I'm fairly I've never seen happen to Bob when he does clouds, but does to me every time, is the fan brush ends up clumping up in bunches (it ends up looking a brush with 5 massive bristles on it).

So coming back to the aforementioned Winter Mist painting, I tried doing clouds to cover the base of the mountain, but all that did was push around a light green colour, so I thought I would tap the brush (which is what you can see in the picture), and, well, that didn't work either.

In the end, I've given up with this painting, but I could really do with some advice as to why the things I'm seeing are happening. What is it I'm doing wrong?