I don't what happened but for some reason my Photoshop CC is only painting in black and white and none of the colours will show. I tried opening a new file but it does the same. For some reason it creates a channel called Gray and now nothing is colour. How do I fix this please?
Your document is in grayscale mode, where only gray values are possible.
Change the mode to RGB, CMYK, or LAB to use color.
How do I change it to RGB?
Or just create the document in RGB by setting the mode to RGB when you create the new document.