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Discussion Starter · #1 ·
Some of you know that I painted my Flat white wall "Pebble Beach"(grey- Benjamin Moore), and then top coated it with 2 coats of 780.....


I setup my AX100 ( DT500 bulb blew up), and compared it to my 3(?) year old 57" Hitachi CRT RPTV...

The Hitachi resolves more detail, even at the same size screen(tried all sizes), even though I am feeding it 720P (it's native 540P/1080i), I have compared HD and SD, it doesn't matter, the Hiatchi resolves more detail (SAME light conditions- same distance from screen).

The Hitachi even has a worse connection, they are BOTH into a COMPONENT switch, but the Hitachi is 2 cables(30' and 9', with an extension coupler!! -Mistake), while the AX100U is a 3' cable......


I am aware of the 'Smoothscreen" technology, but supposedly the newer units are much better than previous models, and it is LCD vs CRT.......


Anyone notice the Behr 780 topcoat soften the pic at all? I used 2 thin coats.


Thanks for any insight.


m
 

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Discussion Starter · #2 ·
I think it does a lil bit.


I painted a piece of wood with the Pebble beach paint that I had left over, and put it against the screen ( flat).


With the 780, I cannot really see the LCD panel SDE, WITHOUT it, I can actually see the grid a bit (this is up close), numbers and stuff, also are a bit smaller edged(clearer).

The problem?

I can see that the whites are much improved with the 780 topcoat, without it, I can actually see the fact that the screen is GREY ( I probably wouldn't realize it, if it weren't for the fact that I KNOW that it is), this is actually pretty EZ to see.


I may have to invest in a different option now, I can see a difference between the 2, it is rather clear to me in both directions.


I never checked the CRT VS DLP, because my room wasn't setup to really allow that, but it obviously would have shown the same thing, but it may/may not have shown itself as much.


NOONE has noticed this?


BTW, this was my MAIN concern about the 780 BEFORE I even did it, it's a coating, and I thought it may cause this.........
 

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muzz..


back when i used a similiar nearly similiar all poly topcoat called 'black gold' on my black flame screens... i found the same thing you are experiencing. it was for this reason alone (softning/defocusing of the image) that i ceased using a poly topcoat and found better ways to increase the performance without having to use a topcoat altogether.
 

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Your second experiment is much more valid than your first IMO comparing a RPTV CRT to a front projection (digital) side by side or separately even at the same size screen is going to have a lot of variables besides the poly you are comparing.


The best test is the one you did comparing that same paint with and without the poly. And if you can clearly see a sharper image in that test then you are right in your assumption I would say.


Now the question is that really a bad thing?


No screen is intended to be viewed so close that you can see the pixels defined and if this is breaking that pixel edge somehow a case could be made for that being a good thing. That's really up to how you see the image.


I have long made a case for canvas and other textured materials to be painted because I felt that fine texture helped if a slightly diffused reflected image is desired. Its not exactly the same thing but similar.


Poly added to paint increases the surface sheen is what I think happens. Surface sheen acts as a mild angular gain improver. When I did tests with pure poly there was an inordinate jump in gain when I went from paint poly mixtures where the percentage of poly was very high to pure poly. I never knew what caused that and I still don't. I also never tested the 780 poly.


Tiddler has some explanations in his FnEasy thread as to how light interacts with the pure poly top coat.


PB_Maxx stated above that he eliminated topcoats completely in his more advanced mixes but I don't believe he eliminated the use of poly. The mixes I made I called the poly paint blends a top coat only because I found no reason to use the poly in the first few coats of paint as I was just building up a base of paint on the screen. So it was more for economy than light science.
 

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Quote:
Originally Posted by pb_maxxx /forum/post/0


muzz..


back when i used a similiar nearly similiar all poly topcoat called 'black gold' on my black flame screens... i found the same thing you are experiencing. it was for this reason alone (softning/defocusing of the image) that i ceased using a poly topcoat and found better ways to increase the performance without having to use a topcoat altogether.

would you share the better way?


Thanks

David
 

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David,


nothing special really... the changes i had made, i've shared here on diy before.


removal of deep base, increased metallic ratio, considerable removal of silver metallic to address the issues of lamp black and it's possible negative effects, increased rgb content, and maintained the poly to about a 1/3 of the entire mix.
 

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Quote:
Originally Posted by D Wulf /forum/post/0


would you share the better way?


Thanks

David

David


I see you have been a member for around 6 months now and as of late have been doing some screen experimenting. I have to assume you have done your share of reading and tried a poly topcoat from another post you have made.


If you don't know anymore after reading the last post answering your question than you did before I don't blame you. I just read the reply and I have not a clue what was suggested to you beyond that fact that poly alone is not good and somewhere on the forum you can read more as to how do some stuff like remove the deep base, increase your metallic while removing your silver metallic, that will stop lamp black issues, then up the rgb and add a1/3 poly to that.


I have made 1500 posts here in DIY and read 100 times that number and I don't know what any of that means.



If you have any questions or concerns on the paint you are now using or want to try for more improvement ask away and we'll try and get you some kind of a plan o point you in the right direction.
 

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The only surface that wouldn't soften the picture would have to be perfectly flat and 100% opaque at the surface, returning all light from a single plane.


Any mixture which allows light to penetrate at all will soften the picture to some extent, since that light which penetrates does not necessarily return from exactly the same spot it entered.


Behr 780 over a basically opaque paint would present two surfaces for reflection: the top of the 780, and the top of the paint.


Any mix containing metallics or pearls will allow some penetration, and thus present several levels from which light can reflect. The more translucent the mix, the deeper the penetration, with a greater opportunity for a different light return path. On the extreme end of the scale would be "fusion" screens, which may return some light from a much greater depth than any other screen technique.


As Bud says, I don't see this as a bad thing at all. A certain amount of softening will reduce SDE, and nearly all commercial screens have a degree of texture which accomplishes the same thing. Actually, I think controlled light penetration is the key to a good DIY mix, and here's why:


The totally flat opaque surface mentioned in my first paragraph can only present its actual surface area, i.e. a 4' x 3' screen could only present 12 square feet of surface area. If the surface has a physical texture, a greater surface area is presented, due to the "hills and valleys". These hills and valleys can also be placed beneath the actual surface using a combination of metallics, pearls, and translucent carriers such as 780. This method produces what I call an "optical texture". Either way, this texture can definitely be beneficial, since there's more area for light to reflect from. The trick is to balance the "texture" so that the increase in light is not offset by the defocusing effect of multiple light paths.


That's my opinion



Garry
 

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Discussion Starter · #9 ·
Hey Guys,


Thanks for the input.


Before I even considered a poly top coat, I thought about this very thing, but after looking over some comparisons(side/side), I figured the better whites would make up for it.

I see that it DOES help the whites, but it IS softening the pic a bit...


With the PJ I have now, SDE isn't even a problem, I had to get very close to the screen to see the sde at all, with the 780, I could barely make it out, without it- I could see it NP at all, but I would never even begin to be able to see it at seating distance.

If I had the Z5 or something like that, then yeah, the 780 is probably a good thing..


I'd like to preserve the whites, and still get the clarity of paint without the top coat.

I really didn't want to get into crazy mixes and spraying.......... ARRRRRRRRRRRRGH!!!
 

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Good post Garry


If anyone wants to see first hand how light travels into the depths of paint layers and then is reflected or absorbed they should view this thread started by member Tiddler.

http://www.avsforum.com/avs-vb/showthread.php?t=713810


The whole thread is excellent and informative but starting around post #11 an idea was born and action on it was taken up around post #36 and 37. It shows a large sheet of window glass painted with screen paint and pictures were taken after each coat of paint from both sides while being projected the same image each time. It shows how much transmission there was with only one coat and as the layers build the visual of the image diminishing on one side while strengthening on the other tells a lot.
 
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