Breakthrough in ambient light rejecting screen - Page 4

Fred
Glad you enjoyed it, and also glad you saw the connection.
I actually saw the effect of this long before the light came on for me. It was kind of like going on trust from what others said. The more I got into this idea of a neutral shading of white it became clearer to me. Then when I realized that in most paint mixes the pigments really don't combine but just sit there side by side as tiny particles in varied proportions. It's the fact the pigment particles are so small our vision can't resolve on just a single bit of pigment we then see them as a combined reflectance. On the other hand light striking the surface reflects or is absorbed particle by particle.
Like a mixture of salt and pepper the salt sending back most of the color correctly because it's white and the pepper absorbing most. That's in paint.
In the case of my paper screen even though the paper looked pretty black it wasn't a pure black body. It had some surface sheen and was a very dark shade of gray I'm sure. I didn't think to measure the surface temperature of the screen before and after projecting but that extra energy was going someplace and my guess is heat.

Fred with the new projector if you have a few lumens left over don't be afraid to try some of the mixes here now. And don't be afraid of gray messing the whites up to much. As long as you have enough light you will be ok. And much better IMO than a ND filter for those with extra lumens.

Not much surprises me here ether anymore, but I'm pleasantly surprised you are still reading the thread.

Krholmberg

That was pretty much what I wanted people to try with that thread and report back what worked and why.

One of the problems I have or most DIYers have is I just have one projector. Its my belief that suiting the projector to the screen is a big deal. And not just the projector / screen but also screen size and ambient room lighting levels.

That's partly why I tried the black screen experiment. I thought what can I do at home in my basement testing lab / home theater that could simulate different peoples projectors and conditions. And knowing my projector is of fairly high lumens I thought I could get an assortment of ND filters and by using them I could mock up lower lumen projectors kind of I also saw I could move my test screens in and out to get different FL readings under these different light levels. That's when I thought ok I can get to any FL I need by moving the screen and if I relate them to neutral gray scales and see ambient performance improvement as FL go up how far can I go. Thus the black experiment. Sure that was an extreme example.
But I read a lot of posts where people are using projectors like the AX100 you mentioned shooting to some pretty small screens. Keep in mind each time you half the throw distance the FL go up by 4. so a 60 inch screen is 4 times as bright as a 120 inch screen.

Last week member movielvr2006 commented on how dark a neutral gray he went to with a smaller screen size and a fairly bright projector. And the great black levels he was seeing with some ambient.

So yes its out there if anyone wants to experiment with the idea.

Tiddler

Finally lol

I have been trying to get across for some time just how slight a shade of neutral gray I have been advocating. And how big the results can be. I would put my projector in maybe the top 10% when it comes to brightness and the shade of neutral gray I selected is way down the sliding scale of grays that are talked about here.

Do the comparison as Tiddler mentioned I prefer comparing samples one at a time against a white screen. I used BOC as a base and advocated that in my thread because its something cheep and also something everyone can get their hands on a yard of. That way when we talk or view screen shots we are all on close to the same page.

I actually did my comparison at first with just the small paint cards you get for free at the paint store. I wasn't looking for overall PQ just areas on a frozen image where white and black came together. The slightest of gray deepened the blacks just as Tiddler said and whites seemed to change very little. There was a point when I could see a slight diminishment in white and that's where I stopped.

The resulting image was LOTS better than white alone and then the addition of the poly paint blend gave a slight improvement in brightness but gave an overall PQ increase in appearance. The word I want to use is not right there and it's something you have to see to know if its what you like. Glow, Shimmer, Transparent, Pop. Pick one

I ended up tailoring my screen to my new projector set on eco mode and brightness at zero with no boosts color 7500k all other settings at zero. I did this knowing throughout the life of the bulb I would need to bump it up from time to time by some means. That's how I would suggest others approach this also.

Side note: conventional wisdom tells us that lampblack mixes are known to result in a blue push. When calibration showed and I concurred by my own taste that 7500k was right for me based off of skin tones etc. I was once again a little surprised. I would have thought I would have had to go to a warmer 6500k at least.
Still haven't figured that one out.

Tiddler

First off I did change the title on November 1, and also added a lengthy disclaimer not to the end of post 1 but to the beginning of it. I can't help it if someone only reads the end of a thread and makes some assumptions as to what is going on in the thread. I often read the last entries of posts I haven't been following but I always take the time to go back to post 1 and try and find out where it all started. And I do at times skip the bulk of the center of a thread if it's something I'm only slightly interested in.

I did not though start the thread as a joke and I didn't infer that in the amendment to post one. In fact I was trying to demonstrate a real world, true, aspect of projecting to a neutral gray screen, and the fact that the darkness of the gray doesn't inhibit the reflection of the color white.

I did craft the thread in a method most are unaccustomed to me doing and in doing so I think I drew attention to the thread and also made something a bit boring more fun. That was my goal but many didn't get it. The fact that some didn't get it and became emotional within a hour of the first post did illustrate the knee jerk reactions that seem to run rampant only in this forum.

(People keep in mind this is FUN!!!)

The nice part of it was some people did get the point and at least a dozen have written and said that the thread and the illustrative photos caused a light to come on in their way of contemplating a gray screen, and at the same time enjoyed trying to solve the puzzle.

The ironic thing is this thread raced to 3 pages and surpassed the thread I started laying out the exact same information in my original (simple screen paint) thread.

I do believe from PM's I have received the thread brought several new minds into the forum that might stick around and contribute.

Krholmberg

I'm glad you read thru my other thread and I'm assuming that's the approach you were talking about following.

Don't make a 112 pure black screen. ok unless you have a very bright room and a huge light canon.

I do understand the problems associated with trying to make a screen in sizes larger than normal materials come in. that's what I was faced with and why I started the canvas screen thread. Pretty much finishing a smooth wall and painting it is the other approach and also the large plastic sheets like MM often shows.

The screen I built looks a little harder than it is but I wouldn't call it simple. My friend just built a variation on it and he didn't have too much trouble.

I also hope you review all the screen types and screen surface options throughout this forum and make an informed pick based on your room, projector, budget and abilities. Good luck

Oct 30 2006 was a fun day watching the replies to this OP come in and the subsequent banter.

Prof55
I was going to give it a bump but I read some place today that doing that is self-serving or something. So thanks for doing it for me.

Actually I was hoping the thread would pass into the archives and I could wait a little while for enough new comers to move in that I could start it over again and have all that fun again.

Oh I'm sure I can figure out something new now.

This thread was kind of sticky the day I posted it. It's not quite as much fun to read with the disclaimer in the OP before you read it but it's still fun and somewhat informative.

I'm still waiting for a 50,000 lumen projector so I can go black on my 120 screen. for now best I can do is gray.

Thanks for reading guys.