You know what there is a subtle schism between imagination and manifestation.
There is a good reason for this.
I take manifestation as also doing or making when the idea is manifested.
You see imagination is wide-ranging open to all possibilities and is a thing of the mind. It is not limited by ability. This is very prominent and easily observable in an artist working and trying to manifest his ideas. There is no technical ability required in imagination but technical ability is required in doing or trying to deliver the idea or to make it.
Also when you use technical ability in art, you find that the work can be quite dry. Good for portraits and such, for commissioned works, like making a chair, something functional to put on the wall, but to see the magic of the universe come out on a canvas you need to make like you imagine, free to make and free decide and free to deploy what is in the mind without technical ability to slow things down and impede mark making.
Jackson Pollock is an extreme of that freedom in mind and manifestation:
John Hoyland has more control over his mind and mark-making:
If you want more control but still stay lose I would recommend Jock McFadyen.
I remember he described how he started a painting to capture the light at night down below him. How he stacked his canvas by the scene and started painting to capture the light at night which he does quite well. Well-spoken and worldly in mind and respectful of others kind of painter:
You can see some of these marks are not deliberately made, perhaps remances from the first layer of paint during the plug and play phase.
Imagination and doing in the thinking mind: Imagination is free to wander and wonder and yet manifestation is limited by interpretation and technique and FORM and doing.