Home Theater Forum and Systems banner

Status
Not open for further replies.
121 - 140 of 1474 Posts

·
Registered
Joined
·
2,234 Posts
Discussion Starter #122
benven said:
On another note, what is the difference between using aluminum flakes and the silver mica flakes that I have been using? I easily attained a neutral, or really close to neutral, paint mix with them.
From what I see you're only using .27 ounces of the Pearl Silver for a quart of the main mix. That's why you don't see a color shifting. That's less than 1% of the entire main mix. The other 'popular' pearl/poly topcoating mix uses 2-4 ounces of craft grade mica. That's 6-12% of the entire mix, and a significant difference. And if you agree that is a big difference, BW PFG uses a whopping 20% of the aluminum component for a 40oz mix. I'm positive if we had 20% mica/pearl in any mix it would be unwatchable.

As far as aluminum over mica- One is a non-interference, the other an interference method, which is another factor and why I was so interested in it.

With lighter colors micas are a bit more forgiving but color shifting is still there. When things go darker color shifts are more apparent.

With just a 10X magnification the color separation is easily seen with Jacquard Pearl-Ex Silver.


This is just a fact of what mica (pearls) do. It's why they are used by artists. Non-interference materials are opaque and do not allow light to pass through them, so the light is not refracted. Mica is a trade off that's been used for years. It makes for a brighter image, but causes color shifting. Aluminum (non-interference) also creates a brighter image but doesn't have the classice mica rainbow color shift effect.

benven said:
Not to nit pick. But 0.8-1.2 is a 50% difference in gain!! That alters L alot. If we say unity gain +/- 5%, that would make more sense to me. That isn't too difficult to hit. It just seems pointless, to me, after doing all that work to get a neutral gray that you would ruin it with such a gain spread.
Unmolested neutral gray in a flat or matte finish is naturally around a .8 or lower gain depending on how dark of a shade it is. Going from .8 to .9 is pretty easy. Getting to 1.0 from say a .8 surface gain starts to have an effect on things, but still not enough that the average person would notice. Going from .8 to 1.2 and the viewing cone not only starts to become noticeable, but specular gain starts to overtake the native 'gain' of the shade of gray alone. Once you breach a .5 increase in gain viewing cone starts to drop faster and off axis color shifting becomes more apparent unless careful steps are taken to counteract the color shift. There are no known steps that can compensate for viewing cone as gain goes up, well not totally true... that's when a torus screen comes into play... It is however true when it comes to flat screens.
 

·
Moderator Emeritus
Joined
·
3,772 Posts
I have a question about the prism effect of mica: Since my PJ only has red, green and blue filters on the color wheel, in theory (there's that word again :bigsmile:), I shouldn't see any prism effect even if it is present because no "white" light is hitting the screen.

Do most of the more expensive, or better, PJ's have a white (or clear) section on their color wheels that this is so important?
 

·
Registered
Joined
·
2,234 Posts
Discussion Starter #124
I have a question about the prism effect of mica: Since my PJ only has red, green and blue filters on the color wheel, in theory (there's that word again :bigsmile:), I shouldn't see any prism effect even if it is present because no "white" light is hitting the screen.

Do most of the more expensive, or better, PJ's have a white (or clear) section on their color wheels that this is so important?
Even with a DLP that just has an RGB color wheel, it is additive color. All colors combined create white in an additive color system. With paints it's a subtractive system and when you add all colors you get black.

Rarely does a projector put out just one of the primary colors. It is creating a complex image of light and colors created from the primary colors in the color wheel or the LCDs in an LCD projector. When light is refracted, it is broken back down to it's individual colors, hence the rainbow prism effect happens. I'm not being argumentative at all, this is the nature of mica is all.

Iridescent materials are covered in detail here.

There are also different grades and quality of mica, which also are a factor. Lower grade mica/pearls tend to have less consistancy between flake sizes, thickness, density of how many flakes per bottle... lots of variables, but they all do have a common characteristic...

Aluminum is a non-interference that is also very bright and reflective, which is exactly what sparked the interest in using it. We can go darker in shade, add more aluminum, and still maintain whites, blacks, and color reproduction.
 

·
Moderator Emeritus
Joined
·
3,772 Posts
Thanks for the reply Bill. I want to be clear that I'm not being argumentative either, really, I'm just trying to understand this correctly. :ponder:

Great treatise on iridescence! :T

Perhaps Texas Instruments is simplifying the matter too much, but their explanation of how a single-chip DLP projector works ( http://www.dlp.com/tech/what.aspx ) says, in both text and graphic, that the DLP chip is struck by only red, green and blue light (the light that passes through the color filters on the color wheel), thus only red green and blue light hits our screens using such a PJ, and only one color at a time. It is the "persistence of vision" of our eyes that makes us see the full visible light spectrum. As I'm sure you know, it is the same phenomenon that lets us watch a CRT television without seeing the even and odd scan fields, but rather one image that doesn't flicker.

If what T.I. says is true, I don't understand how iridescence can come into play with such a PJ. :dunno:
You have MUCH more experience with this stuff than I do, and if you say iridescence is a problem I believe you.

The next time I have my PJ in my "lab" I'll do some testing and see if I can work this out so I finally "get it". :nerd:
 

·
Registered
Joined
·
69 Posts
From what I see you're only using .27 ounces of the Pearl Silver for a quart of the main mix. That's why you don't see a color shifting. That's less than 1% of the entire main mix. The other 'popular' pearl/poly topcoating mix uses 2-4 ounces of craft grade mica. That's 6-12% of the entire mix, and a significant difference. And if you agree that is a big difference, BW PFG uses a whopping 20% of the aluminum component for a 40oz mix. I'm positive if we had 20% mica/pearl in any mix it would be unwatchable.

As far as aluminum over mica- One is a non-interference, the other an interference method, which is another factor and why I was so interested in it.

With lighter colors micas are a bit more forgiving but color shifting is still there. When things go darker color shifts are more apparent.

This is just a fact of what mica (pearls) do. It's why they are used by artists. Non-interference materials are opaque and do not allow light to pass through them, so the light is not refracted. Mica is a trade off that's been used for years. It makes for a brighter image, but causes color shifting. Aluminum (non-interference) also creates a brighter image but doesn't have the classice mica rainbow color shift effect.

Thanks Bill. I guess I should have explained myself a bit better. I should have stated....what is the difference between aluminum and silver mica when put into a paint mix or media? The refractive properties of coated mica flakes and the reflective properties of aluminum must change. I have no scientific proof of this. But using common sense, when mica flakes are mixed into a paint or some other media, how do their properties change? The refractive properties would have to b e different? mech has stated he did not see the prism effect with the mica powders I have used. I assume the reflective properties of the aluminum flakes change. Maybe this requires more discussion/investigation.

And yes, my bad mech, I shouldn't have hijacked this thread :sneeky:
 

·
Registered
Joined
·
2,234 Posts
Discussion Starter #127
Thanks for the reply Bill. I want to be clear that I'm not being argumentative either, really, I'm just trying to understand this correctly. :ponder:

Great treatise on iridescence! :T

Perhaps Texas Instruments is simplifying the matter too much, but their explanation of how a single-chip DLP projector works ( http://www.dlp.com/tech/what.aspx ) says, in both text and graphic, that the DLP chip is struck by only red, green and blue light (the light that passes through the color filters on the color wheel), thus only red green and blue light hits our screens using such a PJ, and only one color at a time. It is the "persistence of vision" of our eyes that makes us see the full visible light spectrum. As I'm sure you know, it is the same phenomenon that lets us watch a CRT television without seeing the even and odd scan fields, but rather one image that doesn't flicker.

If what T.I. says is true, I don't understand how iridescence can come into play with such a PJ. :dunno:
You have MUCH more experience with this stuff than I do, and if you say iridescence is a problem I believe you.

The next time I have my PJ in my "lab" I'll do some testing and see if I can work this out so I finally "get it". :nerd:
What they say is true but you have to keep in mind we see a complex image that is produced by the projector. In order to see the image and colors, mirrors are turned on and off to control the pixels, and the color wheel sends the light. To get a color other than red, blue, or green it rapidly passes light through different color segments. Our eyes combine it into the 'color'.

The reason I talked about iridescence was you asked about the prism effect of mica. I see what you were getting at now though.

I really don't think the type of screen you are talking about is feasable, and definitely not by any DIY means that I know of. I suppose a person could play with Red, Green, and Blue transparant films laid over top of each other, but I'm not sure how well that would work. Translating transparant sheets to a translucent paint would bext to impossible to control the outcome on our level.

Also it seems like this type of screen if it worked would be exclusive to DLP projectors would it not?

Might make an interesting thread if you want to start one up and check into it.
 

·
Registered
Joined
·
2,234 Posts
Discussion Starter #128
Thanks Bill. I guess I should have explained myself a bit better. I should have stated....what is the difference between aluminum and silver mica when put into a paint mix or media? The refractive properties of coated mica flakes and the reflective properties of aluminum must change. I have no scientific proof of this. But using common sense, when mica flakes are mixed into a paint or some other media, how do their properties change? The refractive properties would have to b e different? mech has stated he did not see the prism effect with the mica powders I have used. I assume the reflective properties of the aluminum flakes change. Maybe this requires more discussion/investigation.

And yes, my bad mech, I shouldn't have hijacked this thread :sneeky:
One thing to note is the Micro Pearl seems to be a much finer size of flakes as compared to the craft paint pearls. I think that is the biggest factor right there, better quality.

Even mixed in paint, unless the paint is a heavy clay based paint, or loaded with Ti02, it will have some translucent properties to it, at least on the outer surface. If it didn't, then it would just cover the mica and what would be the benefit of mica, aluminum or anything mixed with the paint itself? But paint does allow light to penetrate to a point. Aluminum will reflect the light back without any of it passing through the aluminum flake. Mica is translucent and allows light to pass through it, and when the light passes through the mica it gets refracted. That's what causes the sparkles of colors we see.

I think if a major amount of micro pearl were used then you would start seeing the iridescent effect begin. Like I said, I believe it's because this is a finer particle size that is the real key.

Can you see from the 10X shot of the Pearl Silver though that if that was added at a higher concentration than what you used color separation definitely would show up? Not a slam or anything, just my observations. Ben I am almost thinking you could drop the Pearl Silver from the main mix and not even notice. That might be a topic for the CG thread though.

There are some companies that make a Ti02 coated mica, but honestly, I'm not really sure what the benefit of that is over getting a high quality paint that is already rich Ti02.
 

·
Moderator Emeritus
Joined
·
3,772 Posts
Hi Bill,

You're misunderstanding me, but rather than continue to talk about this in this thread I'll start a new one. :T
 

·
Registered
Joined
·
17 Posts
Re: Black Widow PFG

So look for that to be coming in the next few weeks... the prototype worked, so now it's time to build the real McCoy.[/QUOTE]

Hi, wbassett. I been away from this forum for several months while researching and trying to organize the purchase of my first projector. Hopefully my Epson Powerlite HC 1080UB should be coming in today.

I've been trying to decide how to go screenwise (since I can't afford to buy a manufactured one) and have been intrigued by the notions of Wilsonart laminate, pvc vinyl and painting.

As an American currently living in Australia I do find that much of the great advice given on these fourms is not really applicable to me with regards to material availablity.

If my Epson can handle it, I would like to build a screen 12 to 14 foot wide which, if the projection calculator on Projector Central is correct, would give me a screen height of between 6.7 and 8 feet.

I can get Wilsonart laminates here but the biggest size is 12 ft. by 5 ft. (too small for my screen.)

I looked into the pvc vinyl from Dazian but for the size I want I would be paying about $1400 plus the shipping cost from New Jersey to Sydney Australia.

Suddenly a sheetrock wall painted white or this aluminum is looking pretty good.

Which brings me to Black Widow PFG. Some questions for you, if you don't mind.

What are you guys painting this on to. The Wilsonart laminate?
Sheetrock? Canvas?

I will re-read these forums posts, but since most of your successful results seem very product specific, it may be that I'm back to square one or reduced to expensive experimentation myself. (or have my friends in L.A. ship those massive paint cans to me).

Thanks, wbassett and I look forward to seeing how the new screen build turns out.

Kane
 

·
Registered
Joined
·
2,234 Posts
Discussion Starter #131
Welcome to the Shack kane!

I wouldn't paint laminate, it's just too expensive to use as a substrate. Other than that, anything you can paint you can apply this to.

Can you get either Henry HE558 down there or Creatix Auto Air Aluminum fine? That's really the key, if you can get it. Dick Blick sells AA Aluminum, but I don't know if they ship to Australia, but don't see why they would not. if you can get it, next question is what brands of paints do you have available, or can your local stores call up color matches for Sherwin Williams or True Value? If not, could they contact them and ask for the color code?
 

·
Registered
Joined
·
17 Posts
Hi, Bill.

I'll have to see what's available here. I haven't been off the computer since I first read this thread.

Hardware store can do matches so if I can't get the actual products I can get the color codes from here and match it.

As Mech or you or one of the others said, my best bet is probably to see how the Epson looks on my white wall first.

Off to call the audio store about my projector. It's been two weeks since i ordered it. epson says no problems with supply, but I don't know why it's taking so long since there are only 12 outlets in the whole country.

As Prof. says "Home theatre....the never ending story."

I'll let you know what I find out.

Kane
 

·
HTS Senior Moderator
Joined
·
8,367 Posts
Hi Kane and welcome on two counts..

Katoomba is nice country...watch out for the bushfires though!!..

Stealing my motto eh!!...:nono: :bigsmile:

I'm also looking at the possibility of making up a Black Widow, but as you mentioned none of the brands suggested are available here..

My feeling is that we will have to find a close base paint, perhaps getting a US paint matched to a local colour..and then experimenting with various silvers of local brands (none of the mentioned ones being available here again) using standard paints, craft paints, artists paints etc..
 

·
Registered
Joined
·
2,234 Posts
Discussion Starter #136
Prof/Kane... Dick Blick does ship over seas, granted it would probably cost four times what the Auto Air costs though :(

The other question would be... would they send aluminum paint and would it clear customs?
 

·
HTS Senior Moderator
Joined
·
8,367 Posts
Short answer Bill...NO..
As I mentioned recently, you can't ship any canned paints into Aus. or post between States in Aus., without a special permit, reserved for importers and distributors..
Within Australia, you can road deliver paints between States but it can get expensive for just a couple of cans..

Kane who is in New South Wales and me in South Australia, would need to be able to access the same brands of paint to maintain the correct colour base, plus the same alum. additive..
 

·
Premium Member
Joined
·
560 Posts
Short answer Bill...NO..
As I mentioned recently, you can't ship any canned paints into Aus. or post between States in Aus., without a special permit, reserved for importers and distributors..
Within Australia, you can road deliver paints between States but it can get expensive for just a couple of cans..

Kane who is in New South Wales and me in South Australia, would need to be able to access the same brands of paint to maintain the correct colour base, plus the same alum. additive..
Prof, here's an Australian place to get Auto Air...it ain't cheap at about $40 (+shipping, I assume)...but should be enough for 2 screens. Maybe you and Kane could split it (if it's cost effective to mail paint to each other)???
 

·
Registered
Joined
·
92 Posts
Out of interest I have just received some aluminium raw product in several forms.

My initial tests have shown that because it is so powerful there is no need for a pre tinted product. ie using white with the raw ali I have pulled it down below N7 range(visual). I am current at aprox 5% product with white base resulting with a level aprox N8~N9.

I have yet to do some spectrum readings, if I get time this weekend I'll post the results.

Looking to have some potential already.
 

·
HTS Senior Moderator
Joined
·
8,367 Posts
Prof, here's an Australian place to get Auto Air...it ain't cheap at about $40 (+shipping, I assume)...but should be enough for 2 screens. Maybe you and Kane could split it (if it's cost effective to mail paint to each other)???
WOW!!!...Thanks for that Bill..and they are based in Adealide!!:unbelievable: :yay:
Which of the three types would you recommend?..I presume the fine one..

I take it that you're mixing it with the base colour, so it could still be rolled on?

I will be doing a trip to Adelaide shortly to pick up a few things, so I could get it at the same time and save on the freight cost..

Thanks again for that.:T
 
121 - 140 of 1474 Posts
Status
Not open for further replies.
Top