I have a question about a phenomenon that sometimes occurs when i take ayahuasca.

When i close my eyes i see all kinds of colours whirling around and strange landscapes, sometimes entity's and so on. But i have noticed that often in the visual field, those places that are most colourfull and light become 'grey spots': almost like a photo-negative where the brightest surfaces become the darkest.
It's like seeing spot's when you've looked into the sun or some bright light, but this happens in the dark with closed eyes...

Has anybody any idea on what causes this strange effect?

I dunno what to say man. I can tell ya that actual "photo-negatives" ie, camera flash, on DMT are quite weird in how they shift colors xD.

Maybe the spice wants you to stop looking for pretty colors and pay attention to the whole picture?
This is subjective but, that's the sort of thing the spice would do to SWIM that I know.

I find it much easier to see and understand the visions in the dark. I find lights out in my bed tends to be the easiest way to access these types of visions that are not all-consuming in the visual/waking realm.

With ya there. SWIM hardly sees a thing when there's light. I'll tell ya what though... Go for a car ride (as a passenger!) in the middle of the day on spice. It's a whole nutha ball game . But ya, SWIM does have to be in pitch black to get the most out of his spice. He sometimes wonders what's going on in his brain when he smokes spice in the daytime outside ... It feels really weird.

Yea, car rides seem to potentiate a lot of entheogens, possibly due to the stimulus of speed in addition to moving through the visual realm? I dunno...I find for spice trips, a little light is nice, I find that ultimately, once I'm really getting to/through the veil, the room lighting is more or less irrelevant and it's nice to have some light on the comedown. With ayahuasca, it seems, at least in my experience, that the darker the better. The first time I drank ayahuasca I was blown away by non-visual visions that were so full of alien motifs, and I know for certain that I would not have been able to access these visions in a well-lit room.

Well, the thing is that i always do ayahuasca in the dark. But in my visions with closed eyes i have these 'afterspots' now and then, wich is ofcourse very odd.

hmmmm, that is interesting. do the afterspots interfere with the visions? do they linger into following visions? Perhaps it's no different than a negative in the sense that you can generate one with oyur eyes by staring at an object and then closing them real fast. I get that your eyes are closed, just postulating a possible similarity. In this case then, maybe sufficient "light" is perceived by the brain to make a similar effect for CEVs.

Never taken that myself but I noticed something that rings familiar with smoked DMT runs. It often starts with shifting colours or something, then it "opens up" in black and white. It's not like your traditional gray-scale though, it's as if objects were simply painted black and white. Then, as if I had blinked, the room would spontaneously burst into colours and obscure the geometry. Other times I'll see a the room as I normally see our reality, normal colours with nothing fancy then I'll just spontaneously get rocketed into crazy colours and patterns.

The other thing is that I always see or feel as if someone was staring right at my face from the right. There's always a slight distortion or difference in the color up in that area. At first I thought my sitter was waving his hand in front of me, but he wasn't.