Home Theater Forum and Systems banner

21 - 40 of 70 Posts

·
Registered
Joined
·
41 Posts
Discussion Starter #21
Hi again, thanks for the chat today. what dulux vivid white paint should I get i.e. flat enamel interior????

One thing being a not so bright country lad is..... If a grey screen with additives compared to grey screen absorbs ambient light for a less washed out picture but reflects more light back to the viewer yet the idea of a grey screen is to stop reflection. I.e. why not just have a white screen that reflects more light back than the grey so be it at the sake of a deeper black? Or is the theory that the additives reflect the light back out of the screen after it has been absorbed or does it just reflect the light away from the screen and the white screen reflect the light toward the screen.

White it is for me anyway just would like to understand it more about grey white ambient light projected light gain and N value and how they relate

Jase
 

·
Registered
Joined
·
92 Posts
Heres the code number from a doc I dug up,
Vivid White 620-04912

I might note there is no real advantage to go towards glossy surfaces, infact matt contains more TiO2 than satin as all paint starts as matt and the gloss(flatterning) ingredents are added. Matt is what you want.

With projection, to create black there must still be a carrier of light if ever so small. Then the surface to be perfect would be black to create perceptual deep visual black. However black also absorbs the light that is trying to be white at equal absorbance levels. ie A Black surface may absorb 80% of light, as low light trying to be black or strong light trying to be white. The result would be a deep perceptual black but very dull white as 80% of it's initial luminance is absorbed by the surface.

The grey screen attempts to knock off the base light level to create the black, the N8 lvel is roughly 20% absorbent, thus white is also 20% absorbed. Because the levels are actually log in nature far more white levels are absorbed than black, 20% is a ratio not total amount. However we don't notice too much as we are more sensitive to black level differences than white level differences.

The catch is though user based projectors are typically lacking in lumens relative to commercial grade and can run out of puff, the gains in black level perception are lost to overall performance losses.

In other simple words, stick to a white screen or very near too, and spend more time darkening your viewing environment, finally calibrate as calibration has measurable gains in black level perception and maximises the screen & projector package.
 

·
Registered
Joined
·
41 Posts
Discussion Starter #23
I get the black white thing what I dont get is how you can get increased gain/keep white levels as of a white screen yet absorb the light at the same time. Is it the way the aluminium or opal etc reflect light i.e. does the grey absorb the ambient and projector light to stop it washing out and then the additives reflect more off after its been absorbed?

from what I see they dont have a vivid white matte only flat or low sheen or is low sheen equiv. to matte in this range as flat is only 1-2% sheen?


boarder paint is there any dulux stuff that works? or does it realy need to be material felt or velvet

cheers Jase
 

·
Registered
Joined
·
92 Posts
Use as matt as you can get, if flat is all thats around now(has been a few years so things change)
That number above is probably still the base stock for all internal paint.

For your question about reflective components, The only way to make a screen gain more reflective light is to narrow the focus so that direct light is directed into a focus as a torch does. However keep in mind you cannot amplify the original light, only gather the light. So screen gain is technically a poor discription. Focusing the light just redirects more of the original light back to say a viewer. There is a catch though, screens with high gain discriptions have narrower fields of view, they can also have spectral shifts across the screen surface and hotspot, brighter in center of the image darker toward the edge.

This is why it is typical to find the average manufactured screen between 0.8~1.2 gain with the mass of those about 1.1
A good quality grey screen with a gain of 1 means the manufacture has attempted to balance contrast(black level and or ambient light absorption) with higher gain, narrower field of view without spectral shifts and hotspoting.

It really is a world of compromise and tradeoffs.
 

·
Moderator Emeritus
Joined
·
3,772 Posts
I get the black white thing what I dont get is how you can get increased gain/keep white levels as of a white screen yet absorb the light at the same time. Is it the way the aluminium or opal etc reflect light i.e. does the grey absorb the ambient and projector light to stop it washing out and then the additives reflect more off after its been absorbed?
First of all, visible light is either reflected or it is absorbed by a surface, not absorbed and then reflected. The fact that this "absorption/reflection" theory has been advanced on another forum is just proof they don't understand the physics of light or laws of reflection at even the most basic level. :rolleyesno:

The way you get the white levels of a white screen on a gray screen is by increasing the reflectivity of the gray screen compared to the white screen. This can be done by adding gloss or by adding billions of small "mirrors" to the paint. Gloss basically works by stealing the light from off-axis (from the viewer POV) areas of the screen and concentrating it on-axis. This will create a viewing cone and if carried too far the screen will hot spot. Aluminum flakes or particles work by appearing as microscopic mirrors in and on the paint (gloss is only on the surface of the paint). These flakes/particles are randomly oriented on the paint surface and in the paint layer itself, they don't form a more-or-less solid shiny surface the way gloss does so they don't concentrate as much light toward a central point; this means they are a less efficient way of boosting gain, but they also aren't as prone to hot spotting. Mica particles act in a similar fashion, but their ability to refract light (break it up into colors) needs to be controlled by the paints opacity or color-shifting and shimmering can occur.

Reflective particles actually reflect some light even when they are below the paints surface, but not much below.
 

·
Registered
Joined
·
41 Posts
Discussion Starter #26
Ok gotya finally, that make complete sense in theory now.

How those little additives know where to lie so they reflect light to the POV simply they must be very bright sparks ( geniuses ) LOL

I looked at the picture of hot spotting in my other thread and to be honest in sport games I would say I could put up with just a slight less hot spotting than that to get the dynamics range ( blacker blacks and deeper colours ). I still think I will stick with the white though and convince the wife of black paint in a semi circle on roof coming out about 1m from the screen wall at its deepest point. ( Is that enough to help ) and then paint the side of screen wall and under screen black also ( Its about 50cm on sides and bottom and about 10cm on the top ) Is paint good enough or do I need to use felt ( velvet pretty hard to get here ). hopefully that will do as good a result as the grey screen as I like my whites as I watch ski vids.

I just hope I can now find this paint that smokin Joe was talking about as it seems it was long ago he go the stuff so maybe the properties have completely changed in the dulux paint. There must be a reason why Peter jackson uses Resene and they have a dedicated paint range with some semi translucent base paint followed by the colour over top?????????? Also they have a flat enamel called space coat that corporate's etc use it tinted white pointer (N8.9), 218 214 204. Is there a reason why you would go just off white like this.

Jase
 

·
Registered
Joined
·
41 Posts
Discussion Starter #27
Ok, so they have interior wash and wear 101 or ultrahide professional. flat 0-2% gloss and low sheen 5-10% gloss. There is no Matte in these ranges. ( dulux au site says that matte is 2-5% gloss ) so do I go for 1l of each and mix?

cheers Jase
 

·
Registered
Joined
·
92 Posts
There is a resene filmpro range, which is made for filmset type work. Hard to get hold of though as not stocked by outlets.

Did you have the link or information for P jacksons screen you make mention of?

The metalics of resene, measured all the possibles, and as far as I can see no new ranges of note.
Hence why i got the raw materials of ali paste in various grades of flake.

I found all mixes of ali flake pushed blue and the higher the mix ratio pushed deeper blue shift.

Using clearcoats of any brand can and will most likely tint with age, yellow shift.(resene chemist comment)

Dulux Vivid White 620-04912, just head to your nearest Dulux outlet, look for the base testpots as an example for number. You should also find the number on the white base paint.
The resene white alternatine is pretty close but does contain less TiO2 than the dulux product, an independent chemist advised me of this, who also happened to supply me with the ali flake.
(that outlet shop is in the RED zone for demo at the moment)

You won't get anywhere trying to get spectro readings or other product details like mix ratios of tints in NZ.
The brands are very protective in NZ, infact Dulux had a "sackable" offence policy with staff who disclose mix ratios.
 

·
Registered
Joined
·
41 Posts
Discussion Starter #29
no link for the Peter J thing that was purely word from the tech management guy via phone so who knows there. They said I can get the filmpro but is that any better in their white anyway???????? If you havnt tested it ir heard I'll leave it. As far as aluminium they now have a fine base range rgb of 125 125 127 http://www.resene.co.nz/comn/whtsnew/finealuminium.htm have you seen that.

Re blue push didnt BW AAA fix that with adding it to bermuda beige so surely you can just do that with the ali fine above then test with your spectrophotometer than fine tune?????????

Anyway you have convinced me out of that route to go white The question is what dulux paint is best the pro series or the wash n wear 101 and what gloss level i.e. the flat or low sheen or mixture of the 2 as there are no Mattes anymore.

Did you ask the resene chemist about the amount of Ti02 in the space cote range or was that not around then? as this if it had the same as dulux could fix the gloss level as they have flat enamel which from what i read seems to work better just flat?????

why would you even conceder poly when you could just have a higher gloss level of paint or does the poly reflect more?

I am going to get paint today hopefully. need to know if flat black paint is ok for boarder and ceiling etc or do I need felt instead

cheers Jase
 

·
Registered
Joined
·
41 Posts
Discussion Starter #30
resene space coat uses their premium grade Ti02 and there is 340 grams/ litre and low sheen is 2-4% which is inline with dulux matte which doesnt exist in the range with vivid white base. resene can do a match to vivid white they say there white has a blue push due to the resin in it?
do you remember the numbers for dulux

cheers Jase
 

·
Registered
Joined
·
92 Posts
They do change their mixes year to year, even batch to batch, hence why DIY screens can be additionally inconsistent.

No I didn't know the actual figures of grams/l of TiO2, took the chemists word for it at the time.

The ali metalicfine existed back when I was playing around, blue push all the way.
Resene head chemist sent me pure tints of their range, couldn't find much that helped spectral response that didn't take the RGB values so low that the result was not useable.
In the end the mixes became such a low level mix ratio it became clear that basic white was just as good for all it's worth.

Again for comparison curves(relationship and curves from past years samples), check the xls file on the Mech download.
Look for tab with RW which is resene white(red push) and DW which is Dulux white(No push).

Again the comparison may be outdated and the base ingredients may have altered so I would have to measure/sample current batchs to be certain.
 

·
Registered
Joined
·
41 Posts
Discussion Starter #32 (Edited)
I just found out that resene flat is 1% gloss at 60 degrees and the low sheen is 5% at 60 degrees, I am after aprox 1.25 gain in white base paint ( no tinting )

dulux matte says its 2-5%

Is blackboard paint the best for the side of walls and boarder or is flat black paint just as good

cheers Jase
 

·
Registered
Joined
·
41 Posts
Discussion Starter #33
Hi all.

Just wanted to say thanks for your help. I now have a 140", 16:9 screen painted resene white. I no longer feel the need to use bright mode so get a much better pic. in natural mode. looks great with the black wall and ceiling. Just need to make my black boarder ( cardboard and material/paint) for my 120"screen for max pop when watching movies. I have attached a pic as I didnt manage to upload to thread.

I will enjoy for a bit before calibration

many thanks again

cheers Jase
 

Attachments

·
Registered
Joined
·
41 Posts
Discussion Starter #35
I must say my paint didnt turn out as smooth as planned even though I sanded between every coat even the top coat. Turns out the guy at paint shop gave me the wrong roller sleeve ( aprox. 4mm mohair ). Apparently its for oil based paints.

What is it that will happen to my final picture I view from having a slightly textured finish and sanded top coat. ( sanding was with 220 grit and you can see sanding marks) compared to a completely flat surface and not sanded. ( the paint is flat in sheen ).

cheers Jase
 

·
Registered
Joined
·
92 Posts
The roller length of nap has more effect than specifically the oil based roller. I've used both types, result is much the same. The paint flatterning agents where there is less in matt type paints has more effects on the suface texture, sanding under layers reduces the compounding nature of layers.

I would hesitate sanding the top layer unless you can avoid sanding marks, also wait a few weeks for the paint to really harden, being thick it takes a while. If you don't notice any thing or texture about the image I'd be tempted to leave the surface alone.
 

·
Registered
Joined
·
41 Posts
Discussion Starter #37
sweet, the picture looks great to me compared to the grey I had before. i dont really see any difference in the light between the 2 but when its dark it comes alive even at 140" live hd sport like the grand prix above cant wait to get my add on boarder made to see it at 120"

I cant see sand marks will let harden off for a few weeks and then maybe another light sand. I cant seem to get it consistent with the mohair some smooth and some sharp little peaks like mini meringues. May I find it easier with a normal roller?

cheers Jase

Jase
 

·
Moderator Emeritus
Joined
·
3,772 Posts
I can't give you any specific roller recommendation, just the shorter the nap the better as it will leave less texture in the paint. Rather than try to sand out any remaining texture I think I would try adding an ingredient designed to aid the paint in flowing to a smooth finish. In the States we have a product called Floetrol (a liquid that is basically latex paint without pigment) that does this without affecting the color or gloss of the paint. Perhaps Smokey could recommend a similar product local to you. You could also try simply adding some water to the paint to thin it, but be careful since too much will get it too thin and let it run. If you are literally getting "meringue peaks" (great analogy :T) then the paint is too thick.

As for sanding the final coat of paint, don't; it's simply too difficult to get an even finish over such a large screen this way.

The flatter finish a paint is the less it will show any texture beneath it or in the paint itself.
 

·
Registered
Joined
·
92 Posts
Paint is a chemical process, generally most paints start as matt and flattening agents are added to smooth the finish for gloss types. The agents also thin out the paint of the important true reflective component, TiO2.

Im afraid this is where painted screens comes unstuck, spraying can be better as long as you do dusting type applications, either way the chemical nature again creates the gathering and texture of a painted surface.

There are some options in the resene range for additives, however they are nasty to handle, better to just go up a grade in type, of course you head to the hotspotting issue when you go to far. Lustacryl would be possibly the next choise jase, although I'd do a test board on mdf before mucking about with current surface.
http://www.resene.co.nz/archspec/datashts/search_index.htm
 

·
Moderator Emeritus
Joined
·
3,772 Posts
Here is a link to the Floetrol additive. I did some testing of this to see if it changed the color of a paint and I found no significant change in it's recommended concentrations. In it's pure form it resembles what we call a "deep base" here in the U.S. which is a latex paint with little or no TiO2 in it.

From what I can document on "flattening agents" they are added to paints and varnishes to LESSEN the gloss of these products. I thought things might be different Down Under, but then I ran across this link for an Australian flattening agent and it seems they work the same way as the ones in the States.

While adding some Floetrol (or a similar product) to paint would thin it slightly thus decreasing the amount of TiO2 in the whole mix by a small amount, I sincerely doubt you would be able to tell it by looking at the painted wall/screen, or even under projection.
 
21 - 40 of 70 Posts
Top