This has probably been asked before. I know when I go to sleep that my eyes are not "black", in the sense that I see some spotted colors and so forth. In a dedicated home theater room, this may not be a problem most of the time, unless there is a black screen. When we see an ounce of white, the black really stands out. HOW DOES THIS IMPACT OUT PERCEPTION OF BLACK?

PS I know when I look at the night sky, the eye is limited to the amount, or lack of, light. Does this affect our home theater experience?

Supposedly the eye can detect as few as 3 photoms per second when fully night adapted. So, the projector makers have a very low threshold to shoot for. :p

This has probably been asked before. I know when I go to sleep that my eyes are not "black", in the sense that I see some spotted colors and so forth. In a dedicated home theater room, this may not be a problem most of the time, unless there is a black screen. When we see an ounce of white, the black really stands out. HOW DOES THIS IMPACT OUT PERCEPTION OF BLACK? Our retinas are wired to enhance the signaling of contrast. Black is blacker when contrasted directly with white.

PS I know when I look at the night sky, the eye is limited to the amount, or lack of, light. Does this affect our home theater experience?I do not get what you are saying. Can you restate it?

BTW, the input of a single photon can be signaled to the brain.

Kal

This has probably been asked before. I know when I go to sleep that my eyes are not "black", in the sense that I see some spotted colors and so forth.

You are likely perceiving your own brain states. It is the brain that perceives; the eyes are just an input. Keep in mind that when you close your eyes to sleep, you are creating a sensory deprivation environment. Under these conditions, the brain can perceive self-generated content (imagination) as vividly as though the eyes were open. :)

You are likely perceiving your own brain states. It is the brain that perceives; the eyes are just an input. Keep in mind that when you close your eyes to sleep, you are creating a sensory deprivation environment. Under these conditions, the brain can perceive self-generated content (imagination) as vividly as though the eyes were open. :)It is not as simple as that. The retina, in the eye, is really an extension of the brain and has substantial processing capability. One interesting issue is that the system is constantly operating, even in the dark (one might say, especially in the dark!), and it outputs noise-signals when the eyes are closed. The rest of the brain then does what it does best: it interprets the noise. :)

This has probably been asked before. I know when I go to sleep that my eyes are not "black", in the sense that I see some spotted colors and so forth.I don't recall the name for it, but there is a state where there is nothing visible in our field of view and our eyes tend to see a kind of gray, but with no visible objects. Probably largely from the noise Kal mentioned. For projectors and screens to give us that same state they have to have a low enough black point that we don't see the rectangle of gray. For short transitions from bright scenes even 10k:1 on/off CR can give us a feeling of not seeing anything when things go dark for a short period, but for long periods (say 10 seconds or longer) I think it takes more like millions to 1 on/off CR in order to get the screen dark enough that our eyes wouldn't see anything and it would be as if we were in a cave with no light (where things go kind of gray, but for the whole field of vision and not just some rectangle). Part of how long projectors can simulate this no visible light situation depends on whether we look around. I figure this has something to do with moving the image to new receptors on the back of the eye instead of ones that were just saturated or at least set to a higher level from non-black images off the screen.

--Darin

It is not as simple as that. The retina, in the eye, is really an extension of the brain and has substantial processing capability. One interesting issue is that the system is constantly operating, even in the dark (one might say, especially in the dark!), and it outputs noise-signals when the eyes are closed. The rest of the brain then does what it does best: it interprets the noise. :)

Although environmental light can certainly pass through the eyelids and influence brain activity while sleeping, this rarely happens. What DOES happen is that when the brain is active/stimulated, so too are synaptic connections to the body, which means when we dream, our eyes react to some degree as though they were open. If we dream of running, we are stimulating the motor cortex, and all of those connections to the legs. So basically, the eyes are active when we sleep because the brain is active...and not the other way around.

If two groups are taught piano lessons, one group with only hands-on lessons, and another group with fewer hands-on lessons, but also imagined piano lessons, the group with the additional imagined piano lessons and fewer hands-on lessons will be nearly as proficient as the group that received more hands-on training but no imagined lessons, because imagination/brain activity is stimulating the same neural pathways used in the actual physical act of playing the piano.

The brain is not just interpreting noise. There is a lot happening during sleep. Current thinking is that we dream to explore mistakes or problems, and to explore new choices and possibilities, as well as just having fun. The brain also enters a state of rejuvenation during sleep.

Check out this fantastic book for the latest on neuroscience:

http://www.amazon.com/Brain-That-Changes-Itself-Frontiers/dp/067003830X

Don't worry, no new-age stuff here, just science.

I don't recall the name for it, but there is a state where there is nothing visible in our field of view and our eyes tend to see a kind of gray, but with no visible objects.

--Darin

Sounds like you are referring to the Ganzfeld effect.

There’s also spots and floaters. Clumps and strands in the Vitreous Fluid. I see them even with my eyes closed. Over 40?

Dave

Not sure how you made that logic-leap from my post. Read it again? I'm not skeptical of you nor did I say no. I've experienced my share of altered consciousness. Just offering up yet another reason for ones seeing crap with your eyes closed. You'll be over 40 one day and you'll likely have spots-n-floaters too. Just because one sees hoofprints, doesn't mean there were Zebras. Occam? :D

Dave

Sorry, got a bit carried away there. Deleted my off-off-topic :D posts.

Interesting Info. My first post.

Although environmental light can certainly pass through the eyelids and influence brain activity while sleeping, this rarely happens. What DOES happen is that when the brain is active/stimulated, so too are synaptic connections to the body, which means when we dream, our eyes react to some degree as though they were open. If we dream of running, we are stimulating the motor cortex, and all of those connections to the legs. So basically, the eyes are active when we sleep because the brain is active...and not the other way around.I think you are making an artificial distinction since the neural retina is, in fact, brain and is as active as the rest (at rest). Besides, dreaming is not a constant occurrence while the effects described occur while one is awake but at rest.

If two groups are taught piano lessons, one group with only hands-on lessons, and another group with fewer hands-on lessons, but also imagined piano lessons, the group with the additional imagined piano lessons and fewer hands-on lessons will be nearly as proficient as the group that received more hands-on training but no imagined lessons, because imagination/brain activity is stimulating the same neural pathways used in the actual physical act of playing the piano.Perhaps but irrelevant to the present topic.

The brain is not just interpreting noise. There is a lot happening during sleep. Current thinking is that we dream to explore mistakes or problems, and to explore new choices and possibilities, as well as just having fun. The brain also enters a state of rejuvenation during sleep.Dreaming occurs only during a small segment of sleep time (during REM sleep) and, as stated above, is not relevant to the observations described while awake.

Check out this fantastic book for the latest on neuroscience:
http://www.amazon.com/Brain-That-Changes-Itself-Frontiers/dp/067003830X
Don't worry, no new-age stuff here, just science.Well, popularized stuff but hardly hard neuroscience. Such books are informative for the layman but, in translating the information into understandable language in a familiar context, some principles are often smeared. I wouldn't place all reliance on this or similar.

(My day-job is Assoc. Prof. of Physiology and Neuroscience.)

my eyes are rated at 4,000,000:1 contrast, I had them calibrated by Jason at AVS. I could originally only see 15,000:1 out of the womb.

my eyes are rated at 4,000,000:1 contrast, I had them calibrated by Jason at AVS. I could originally only see 15,000:1 out of the womb.Wait 'til the bulb dims. ;)