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post #1 of 20 Old 04-26-2001, 06:52 PM - Thread Starter
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Tomorrow's the day I paint my DIY screen.
Yesterday I finish building my 47X82" frame out of 1X2 hardwood, all glued and screwed, then added a 4X8' sheet of peg board for complete rigidity...again glued and screwed...over the peg board I stretched a sheet of artist canvas. I have also finished a 2.25" black felt frame that goes around the whole thing...it's made with 2 pieces of 1.125" corner trim glued and stapled back-to-back, the back-to-back part forms the lip that is screwed to the sides of the 1X2 frame...after installing felt frame screen is 80X45.
Today I cleared out one side of my garage (my garage has a wall down the center of it) swept the ceiling and walls (paint is very heavy and will pull dust from the walls and ceiling) then hosed down the ceiling, walls, floor and saw horses that screen will lay on for painting. Cleaned the paint gun's exterior of all dust, wiped down air hose, tomorrow I will even wet my hair before spraying.
Yesterday I also recieved my 1.5 liters of "ScreenGoo" from KBK, so we'll see how it goes on, and how it performs.
I wanted to use some flow release, but I'm afraid it may discolor the paint so I'm going to test spray with light thinning using distilled water.
I've added extra lights to the "spray booth" and will wet the floor before spaying. (this keeps dust from being kicked up by feet)
I would say wish me luck, but all that's need is alittle skill...instead I'll ask you to cross your fingers that I have the skill. http://www.avsforum.com/ubb/smile.gif
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post #2 of 20 Old 04-27-2001, 02:21 PM - Thread Starter
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Well...I have the skill. http://www.avsforum.com/ubb/smile.gif
However it was touch-and-go for awhile, the first two coats went on...not as well as I'd hoped. I didn't use enough water to thin the paint.
Out of the can this stuff is very thick. During the first coats I add approx one deciliter (1/10 liter?) per liter of paint, and approx 1 centiliter of flow release agent...not enough, my spray pattern was to narrow, and while I got good coverage I didn't get it to lay down evenly, plus even with all the above prep work I got a few "imperfections" falling into the paint, I was alittle bummed...down, but not out!
After it tacked up I moved it out into the sun, for some fast drying...I had a plan. (Ken is going to KILL me for this next part, he e-mailed pleding that I not do this!)
After several hour in the hot sun I dawned my finger sander (360 grit sandpaper on the end of the index finger) and sanded all the imperfections down WARNING unless you've done this before don't even think about it, and to add to it, uncured waterbased paints can be unforgiving if you don't know what your doing here.
After getting the imperfections out I brought the screen back into the paint booth, added more distilled water to the paint (total water, 2 deciliters per liter) added a good "splash" more flow release, and went back to painting...first pass vertical, second pass diagonal, third and final pass horizonal...done, laid the screen flat
Much better I got a nice wide spray pattern, smooth even coverage.
This is a very high quality paint, and if mixed correctly and sprayed correctly is easy to apply. I've worked with much harder applications than this, so even for a novice (which is what I am) it's not hard, however beginner is another story, if you have no spray paint experience I'd say hire a pro or at least someone with some spray experience.
The important thing is thinning, waterbased paint don't react well to over use of water as a thinner, hence my reluctance is thin correctly the first time...however this paint is so thick in the first place that a little extra water seems to be no problem here.
One more thing, after looking at the dried first coat this is going to be a beautiful screen, I haven't seen an image on it, but I can tell this is going to look very good!!
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post #3 of 20 Old 04-27-2001, 05:08 PM
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I specifically warned against using any sanding, as the bonding of the layers could be imperfect at the surface junture btween the layers of paint. This would have the capacity to cause a 'dark area' to appear. This is not an opaque paint.. NO PAINT IS. Opacity is a joke, it's realtive to density, and other parameters.

The trick, which you will find out if you pulled off or not, is the drying time of the lower surface, and if the final layer can 'soften and bond' with the underlayer. Then you will be fine. The drying time is so long with this stuff (a full month to clarify in normal room temperatures and humidity) that you should be OK.

It must have practically blew your eyes out of the back of your head in the direct sunlight like that...It is excruciatingly white, and bright.

If you had waited a week, and then sanded, you would be screwed. And, it looses so much mass during drying (water) that even drips (small ones, more like slight running) can dissapear into the surface and be un-noticable during viewing, and hard to find, even on a full white screen image.

I have been using the first made, and badly sprayed prototype for months, with no urge to change it. (well, not enough yet...)

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[This message has been edited by KBK (edited 04-27-2001).]

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post #4 of 20 Old 04-28-2001, 06:29 PM - Thread Starter
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That is the exact reason I sanded it within 2 hours of spraying, I knew that if I waited it'd be harder for the top coat to "bite down" into the base coats. It was either do it when I did, or risk bad adhesion in the sanded areas. I simply chose the one I knew would work.
I'd say offer your product just the way you sent it to me...there are so many variables that to offer it any other way might be asking for trouble.
You have variables in supply pressure to the gun, nozzle pressure, paint quantity at the nozzle (trigger adjustment) and lastly ambient temp, which on a hot day may require a little extra water or flow release. Automotive paint is never offered "ready to spray" just for these reasons.
OH YEA, while the screen was out in the sun I think I got a sunburned face from it http://www.avsforum.com/ubb/smile.gif once I came in my house it was so dark it seemed like night.
Last night the gain on the screen was alittle to high for my liking, but today it is looking better...I'm very happy with the finish product!

[This message has been edited by KennyG (edited 04-28-2001).]
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post #5 of 20 Old 04-28-2001, 09:06 PM
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What happens is that the image that the fresh screen provides is a bit 'hot' due to the high water content; it has not dried out yet. Over the first few days the hotspotting behaviour dies down considerably as the original 'milkiness' of the mix begins to clarify, and the complex mixture begins to be able to deliver it's capacities to the total reflective character of the screen. As the clarity comes up, so does the color intensity. The first three-four days or so will show the greatest difference, and then half again within a week, and then a quarter of that change in the next two weeks or so... and then, that's about it.

As I said, if the sanding is not properly done,and handled, the results could be, uhmmm.. less than optimal. It should be perfectly fine, due to the time period in which it was done, and your previous experience with paints allowed you to predict the right time better than most would.

Once the product has been properly thinned, or the understanding of what kind of thinning is needed has been acertained, then this problem no longer occurs, and no effort is required beyond the actual spraying.

We may keep the raw, unadjusted paint stock available as an item, for those who can handle spraying gear very competently, this will allow them to adjust their OWN mixtures, and get maximum coverage and lay characteristics that they may desire, for any particular application.

I would like to hear comments on this if at all possible.

Oh yes, the product does remain flexable after full drying, with a elastic break point of 300%. This means that it will bond to older matte white pull down screens with proper surfaces (for paint bonding) and will work fine with recoating older screens.(strictly depending on the surface character of the old screen being painted over)

This also means that it can be put on a material that can be streched, like artist's canvas (original design parameters), floor mattings (yes, it makes a tough rug as well) It CAN BE WASHED, with GENTLE soaps and cloth... clean, warm water, please. SO, bar use for large screens is definitely NOT out of the question. Tough enough to hose down at the same time it is an excellent viewing surface. Once you have done a surface or two, your skill level is high enough to make application hassle free.

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[This message has been edited by KBK (edited 04-28-2001).]

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post #6 of 20 Old 04-29-2001, 02:12 AM
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Hi Kenny,

Congrats on a job well done!

Let us know what picture improvements you find using Ken's miracle whip. http://www.avsforum.com/ubb/biggrin.gif

KBK sent me the same thick mixture as you, so I have been extremely attentive to your spraying recommendations. I take it that you used 2 deciliters of distilled water per liter of paint mix, and no other thinner.

Since I am at a very windy location atop a building, it is impossible for me to spray this stuff outdoors. However I will be emptying my multipurpose HT room to put in new flooring, and in the interim will have an indoor surface upon which to spray. http://www.avsforum.com/ubb/smile.gif

How do you feel about the way artists canvas conveys the impression of textures when projecting onto it? Did you have to paint the board underneath the canvas in black to avoid light reflection through the weave? Does a woven surface better convey a sense of the original textures than smooth vinyl would?
For example, does tree bark not only look like bark but also "feel" like you are looking at bark on a real tree - or am I barking up the wrong tree? http://www.avsforum.com/ubb/wink.gif

If I recall correctly, vinyl is said to better convey image depth - the 3d effect. So what should it be: canvas or vinyl? Thanks in advance.



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post #7 of 20 Old 04-29-2001, 03:12 PM - Thread Starter
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Brett, you do not want to paint your screen outside...even on a dead still day, there are so many things either floating in the air, or flying through it, you will get alot of airborne crap falling into your screen. You want an indoor room that is as clean as possible, remember, every step you take stirs up dust off the floor, if your spraying close to the floor or a wall the air from the spray gun will kick up dust. So clean the room very well, keep the screen several feet off the ground and out in the middle of the room. You can stand it up the paint, then lay it down to dry.
I don't know if you have the paint the peg board backing, but I did using "Kilz" waterbased primer/sealer...three coats did it.
The Artist canvas has a tight weave, so it wasn't noticable even before I painted the screen, now the canvas texture is almost gone, the paint filled in alot of it. After two days of drying it is really looking good, the paint is beginning to "tighten up" alittle and many of the small imperfections have simply disappeared. The screen reflectivity has dropped slightly, which I'm glad of, that first night the gain was to high for my liking.
This screen beats the Draper it replaced hands down, no contest...is it better than a Stewart? I don't know, but I think it might be as good!!!
At the price ($265 total) I'll take the DIY every time...Kenny
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post #8 of 20 Old 04-29-2001, 04:06 PM
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************
Brett:
He DID use a material called 'flow release' as well. What that is, is a 'anti-clogging' agent for the spray tip on the spray gun. It helps stop the tip from clogging, and blowing thick chunks all over your nicely spray painted screen. VERY, VERY important for MAXIMUM spray quality applications, which this definitelty is one of.
*************

We also sell the most heavily pigmented (and properly made) artist's acrylic gesso on the planet. We sell it at the normal retail price, which is $25 US per litre, I believe. It is 4 times as heavily pigmented as standard gessos, and with the proper ingredients, with absolutely NO fillers of any kind, something that NO ONE else in the entire industry does. We sell this as a 'backing' paint-drop for those who desire a good, high grade starting surface. It is nearly an absolute perfect 1.0 gain surface, with maximum color fidelity. Makes almost all 1.0 gain matte screens look like chopped liver in comparison. Some might stop there, and not bother with the screen paint.


I am satified enough with what KennyG has been getting with the paint, that I will start selling the raw stock to those who can handle it. This is a nominal rated 1.6 gain white screen paint, for CRT use. Light doping for grey screens can be done with a small amount of our pure carbon black additive, for digital projector use.

e-mail if you are interested. As of this moment, the doors are open for business. The web site is not fully set up for CC useage yet, but I can do things by pay-pal for the moment.

I cannot and will not comment further on pricing and the like, as this is NOT a commercial space. This is a nice HT internet forum, not my own personal sales soapbox. Please restrict ALL commercially oriented enquiries to e-mail with me, don't bring it here. Thank you.

All other questions are welcome, as in coverage, blending, additives etc. All this will eventually make it to the website for users to peruse, and become informed by, but it is actually time to begin gathering such info, so fire away.

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[This message has been edited by KBK (edited 04-29-2001).]

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post #9 of 20 Old 04-29-2001, 05:22 PM
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Ken,

So if I were to add a bit of the carbon black to the raw 1.6 stock would I have a grey screen with some amount of gain to it?

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post #10 of 20 Old 04-29-2001, 08:31 PM
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Definitely.

The higher contrast ratios that are beginning to occur create a situation where the requirements of grey matching vary considerably. Specific targeting can occur if the costing is low enough. Hence the need -with these ever changing markets- for a method of getting to a matching gray. If you think you have your gray targeted, then there is no reason you shouldn't try. We will be creating more advanced pre-made grays, but this trick works perfectly well if your color is currently balanced. Please consider our carbon black additive for such an enterprise.

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post #11 of 20 Old 04-30-2001, 08:01 AM
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1.6 gain screen with paint that retains colour accuracy and does not hot spot. WOW. That is amazing. This must have been a labour of love more than a get rich quick(slow) scheme. Probably a stupid question but have you achieved what you started out to do? Back to the Gray question, when you get around to making the Dila gray will there be a certain gain you will be shooting for? I like the idea of better contrast(how wouldn't) but I am also addicted to a nice bright picture. The reports I have read about the current commercial screens seen encouraging but there is that give and take with contrast and brightness. Do you think it is possible for you to be able to increase contrast by approximately the same as the HC screens that are out there now but also keep the gain above 1. gain? If so when do you plan on experimenting with this? If you need access to a Dila I know where you can get one (uncalibrated)that is close. Keep us informed
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post #12 of 20 Old 04-30-2001, 10:21 AM
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I would like to immediately clear one thing up.. there is a minimal amount of hot-spotting when the paint is used in conjunction with smooth matte vinyl. The gain comes up, but so does the hot-spotting issue. It is very minor though,and tends to be unnoticeable even to me, and I am picky. It only comes up as noticeable, if you are specifically looking for it, on wide, high white level scenes. Any color, and the effect disappears. I am mostly speaking about the colorshift due to the fact that I use CRT. When combined with some of our carbon black additive, the colorshift becomes moot, due to the fact that it will be use with Digital single lens projectors, AND, MOST IMPORTANT, the digital projectors suffer much less from level drop-off as you move off center (screencenter to edge) from the output. More like 15% difference up into the corners, compared to the CRT's problem of 30-35%. So, if I find it to be perfectly fine with CRT use, then Digital projector users should have zero complaints.

The DILA does not suffer from color problems as much as other projectors' bulb and output considertions, so, a CRT 1.6 with some carbon black additive should do wonders for creating a higher gain grey screen. The grey screen that suits YOUR distance and viewing considerations which is what is required for the best image. A specifically targeted screen. There it is. Do you want it?

The reason that I say this, is that the room reflectivity, ambient lighting considerations, calibration of black level, screen size (and hence the Foot lamberts of light producing the image) and lighting up a specific amount of screen area.. This combined with the eye's natural dilation response, etc. This is what gets you to the right grey screen, and the right 'peaking levels' for convincing whites at the same time. All critical, and quite variable from situation to situation. You have to 'dial in' the grey that is best for your set-up. And, the best screen has to be availible to you, and it must be variable, so as to fit your shifting needs. It has to be cheap enough that people can get there at reasonable expense as well. It's your screen, and your projector, your room, your viewing size and distance, and your perceptions. I am not making any judgements on the screen design, YOU WILL. that's not my place. My place is merely to provide you with the tools you need.

Digital projectors vary SO MUCH in their requirements that no single screen design will suffice.

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[This message has been edited by KBK (edited 04-30-2001).]

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post #13 of 20 Old 05-01-2001, 12:21 PM
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KennyG:

I am curious what Draper screen you had before....

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post #14 of 20 Old 05-01-2001, 05:09 PM - Thread Starter
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I had a 1.3 gain, 10 foot, motorized unit. The screen size was wasted as I only used a 45X80" area, I just picked it up because it was a deal I couldn't refuse, it was a stop gap measure between a terrible 2.5 gain screen I got with the projector and my DIY'er
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post #15 of 20 Old 05-01-2001, 06:26 PM
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Ken, I am finding some of what you are saying a bit confusing. I understand that one of the advantages of your system is the ability to get the correct screen for specific projectors but is it not also true that there will be less variables with a plain white screen. If the additives end up not being perfect to the projector you are shooting for you will still have a top quality white hi/gain screen that anyone would be happy to own. On the other hand if this same method is used for a grey screen the slightest mistake or over correction with the black additive could be disastrous. Is there a better way than just sending out the paints and saying go to it?
If for example I have a 106" 16x9 screen and a JVC G-11 Dila (approx700 lumens)and my seating positions are between 11 and 15 feet from the screen at a maximum of 40 degrees off centre and my preference is for as bright a screen as I can get that will also noticeably increase contrast,do you have a premix that will fulfil this goal?
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post #16 of 20 Old 05-02-2001, 06:30 PM
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Quote:
<font face="Verdana, Arial" size="2">Originally posted by Martin P:
Ken, I am finding some of what you are saying a bit confusing. I understand that one of the advantages of your system is the ability to get the correct screen for specific projectors but is it not also true that there will be less variables with a plain white screen. If the additives end up not being perfect to the projector you are shooting for you will still have a top quality white hi/gain screen that anyone would be happy to own. On the other hand if this same method is used for a grey screen the slightest mistake or over correction with the black additive could be disastrous. Is there a better way than just sending out the paints and saying go to it?
If for example I have a 106" 16x9 screen and a JVC G-11 Dila (approx700 lumens)and my seating positions are between 11 and 15 feet from the screen at a maximum of 40 degrees off centre and my preference is for as bright a screen as I can get that will also noticeably increase contrast,do you have a premix that will fulfil this goal?
</font>
You could say that there are no variables with a plain white screen. This would be true. Would you want everyone to drive a LADA? The Politburo would like you to think so...

Perfectly white, medium gain screens are just about all that one can hope for when using a CRT projector.

The CRT is capable of a TRUE black. Complete light cut-off. This means that you can use a white screen,and get perfect whites, and perfect blacks (relative on the blacks, there are ALWAYS some shortcomings).

With the DIGITAL based projection units, there is a problem. They cannot at this time produce a TRUE black. What is needed is a falsified black, or a grey screen. This IS the falsified black level. (If you make the mixture TOO black, that's not good. you would get too much darkness in your shadowing, and your whites would look wrong.. slightly grey.

The very simple trick is to not mix in too much carbon black to the mixture. Get a grey of some sort. It is better for the digital projectors than any white screen, as the colors end up looking much more controlled, delineated, and saturated. In other words, the image appears -to the human perceptual mechanism- to have more contrast range, and better blacks. As I said, a slight grey is better than no grey, or complete white.

CRT projectors require complete white screens, otherwise you are wasting the limited output of such devices. In the same manner, you must conserve the output of your chosen projector,and then get what you need, want, or can deal with.

The very variability of the product may be an Achilles heel to the unadventurous. I will not hold anyone's hand on this. As the database of application notes from users grows, the risk factors will be removed to a large extent, as there will be specific results reported with specific mixes. At first all you can do is try. If you want to wait it out, that's fine. The risk level, financially speaking is very low. The quality that can be delivered by the paint... is very high. Small risk for such high gains to be had in viewing enjoyment.

KennyG took a risk on the product, as he knew nothing about it. Each day he uses his new screen, it gets better, and better, until if finishes drying. About 3 weeks, it takes. SO, if you get the paint, and add a small amount of carbon black, it will give you a great grey screen. What you can do, is play with different greys,and try and find one that you feel is suitable. Then, mix carbon black slowly into the paint until it is matched. Then, paint with the mixture. If your screen is LARGE.. which it probably is, you will need multiple coats anyway. Who says the final coats have to be the same grey?

Lets get real... how much does the perfect grey screen cost right now? and then calculate how many grey screens you can experiment with making, and only end up spending half as much, and end up with a better targeted grey. One for you, and your situation, exactly as YOU judge it, as you are properly, for once, the final arbiter of the screen's make-up.

Remember what I said, there is NO PERFECT GREY SCREEN. IT DOES NOT EXIST! There are too many different projection systems out there, and once you deviate from a true white.. you get into a WORLD of hurt. As I said, once the product gets off of the ground, then I will be introducing specific targeted greys, but even they will be 'minimally' grey colored, and will be set up so certain amounts of extra black can be added to the mixtures, to get them to a specific grey condition. These will mostly be the color corrected mixtures to deal with the changes in color output from different bulb types, and color wheels, etc. Not that economical (to manufacture quantities of paint) until it can be proven that people (and dealers and installers) are willing to go this route. Why they would not want to do so is beyond me. It just remains to be proven in their minds that it is a viable method of attack.

As I said, I will be producing specific targeted mixtures, but not today. You can make your own grey screen with the product, or wait it out. Your decision. To say that -in my mind- it is a simple task to blend up a grey screen that you would be satisfied with.. would be an understatement. It is not difficult at all.


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post #17 of 20 Old 05-04-2001, 11:39 PM - Thread Starter
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Well it's been a week since I finished the screen, tonight I sat down to watch Superman (nice DVD by the way) Before I did I threw up a white screen to look closely at the gain...I think it may be alittle to high for my liking. There is some hot spotting, not to noticable with images, but it's there just the same.
Still reflects a beautiful image, but perhaps a slightly lower gain would be of interest.
Ken, can the gain be reduced on a batch by batch basis? Can you have paint in custom gains, say 1.0 to 1.2, 1.2 to 1.4 and lastly 1.4 to 1.6? I can see a 1.2 to 1.4 mix being my choice...
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post #18 of 20 Old 05-05-2001, 09:01 PM
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Higher gain screens give a better contrast range, specifically due to their lower diifusion level, created by their surface texture, or diffusive characteristic. You will notice that the cheaper white matte screens sometimes have a pronounced patterned surface characteristic. This gives them that low gain and low hottspotting, and low colorshift, but, at the expense of contrast range. Ambient lighting becomes a huge concern. One part of a bright image, can wash out another.

The paint you have used is variable in how it will behave due to the surface it is sprayed upon, how it is thinned and applied to the screen. It is designed to express a nominal behavoir, and to max out at a 1.6 gain characteristic. IT IS very possible to introduce a lower gain targeted mixture, and I will be doing so soon. There are other screens out there that have this gain (in the 1.5 gain area) but have their own inherent problems with color balance. This mixture was designed to be a BASE material to work from. Due to the way it was handled, the screen you have is probaly expressing it to nearly the maximum characteristic of the 1.6 gain... This is where my screen is at, and it was sprayed with a hotspotting white matte vynil as the backing material. Give it another week , and it should have changed noticably from where it is now. It may not get as low as you wish it to though. I will see what I can do for you, if this is the case. I might send you a liter of corrected mix to see if it does what you want it to do. I will be spraying myself a newer screen with a corrected mix first, in about 1.5 weeks or so. If that works out the way I expect it to, then I will send you the new mix to try.

I can drop the gain a little, and will be doing so. This mix is quite good for digital projectors, due to the fact that they do not suffer anywhere as much from hotspottiong issues, and colorshift. They NEED the higher gain response when the formula is greyed with carbon blac additives, so as to keep the overall gain up.

CRT projectors are MUCH harder to satisfy, as they have their problems, and they also posess the subtulty of characteristic to show shortcomings in screens, and can actually give a better image with the right one.

One final comment though. If the hotspotting is not an issue during viewing, and does not draw attention to itself at all during a movie, is it REALLY an issue? Remember, if I cut the gain, you loose that terrific contrast range, at the very least. The gain should drop slightly by the time the paint is dry. Take it outside again for some drying, if you wish to speed the process up. What is happening is that there is moisture trapped in the mix beneath the healed surface. It is causing extra reflectivity. It has to 'wick' out through microholes in the surface. It takes time to have this happen, and have the mix clarify through the drying process.

In my house, in the dry winter, on a vynil screen, it took a full month to reach the final gain characteristic. Truthfully, after another week, it will not change that much from what you have now, but it will definitely be a noticable change, and it might be enough for you. So, give it that extra time first.

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post #19 of 20 Old 05-05-2001, 10:59 PM - Thread Starter
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After watching some differently lit stuff, I have an idea for a screen that addresses one of crt's problems, the drop in light output out at the edges.
Anyone ever tried to create a "dual gain" screen for crt application?
I can see something like a gain "basecoat" of 1.3, with a vertical pass of 1.6 on the outer 24" (both sides) Followed up by an immediate horizonal pass at 1.3 this time 1.6 is also applied horizonally out in the last 18" of the screen. (I'm thinking in 16X9 here so the top & bottom edges don't need higher gain)
Once this dried to a cohesive screen the outer areas would have a higher gain than the center...would this give a preceived light increase out on the edges? Would this even be beneficial?
In a couple bright scenes I noticed the center of the screen was noticably brighter than the outer areas....for that matter if this would work the best way to do it would be to basecoat in 1.6 then spray the center 35" with 1.3...this is fairly easily done by hanging guides 2 feet above the spray surface, your spray gear passes under the guide, but said guide gives you the center 35" inches and spray gun height (as hand and spray gun pass under it, this puts spray nozzles at approx 12" off screen surface.
KBK does this seem viable to you?
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post #20 of 20 Old 05-15-2001, 07:56 AM
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Ok. It's been over a week since I last considered the situation regarding your screen. I suspect that what you had in the way of hotspotting has changed by a noticable amount. It is suprizing how much it changes, but it takes so darned long. That's acrylic resins for you. But, at leat this way the screen remains flexable for as long as it is in use. The paint never hardens. Just curios if you have noticed this slow change in the hotspotting (the small amount it had in the first place).

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