If I close my eyes and try to consciously see something, I see only black or maybe shifting colours. With my eyes open, and not consciously trying to form an i

If I close my eyes and try to consciously see something, I see only black or maybe shifting colours. With my eyes open, and not consciously trying to form an image, I think I can see things I'm thinking about, though not in colour, but as soon I try to form an image, it slips away. It's odd - I'm not even certain I can see things unconsciously this way - I think I can, but I'm not really quite sure - the images are just on the very edge of conscious reach. This doesn't stop me being able to draw or paint reasonably well, and I'm really good at thinking about how three dimensional mechanisms work - I don't so much as form an image as just understand complex shapes without seeing them - but I still cannot just form an image consciously. To the extent I can, I'm more figuring out how I'd draw it than recalling the image itself. The test from the linked article seems to assume people can visualize an actual image more than fleetingly, but that's not me. I'm pretty sure my subconscious is very good at visualization (I certainly can when I'm dreaming), but it's not a conscious thing for me, and the very act that the test asks for - think of a scene - is what causes any half-images to disappear.