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Discussion Starter #42 (Edited)
Well, so far not so great. Honestly I am at a bit of a low point today five coats of the SF application. With a few coats still to go I decided to fire up the Mits1000 and see how it looks so far. The drywall texture was amplified and completely noticeable for the first time. I never saw any texture when shooting to a beige wall or after a few rolled coats of Kilz2. Now it's all you notice.

Texture was a concern I had expressed here and in my conversations with MM. I remain convinced that our walls have light-to-moderte texture but after what I just saw maybe I have to accept that I may have underestimated it.

I decided to try SF for its purported performance in moderate ambient light conditions and high gain. I never hid the fact that I am not a DIY handyman and any shortcomings in whatever result I get may ultimately be most attributable to my inexperience. So now I am waiting to discuss with MM and wishing I would have started out with a simpler application or just gone with one of the laminates. Not sure which direction I will go next....
 

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12th man this is why I was so adamant about doing a baseline. Most people don't do this and it really is impossible to judge improvements when no reference baseline has been established.

I would say though to go ahead and finish up with any additional coatings that are recommended and then let it cure for a few days.

Here are some tips about gain from the Data and Testing Definitions thread:
12 foot-Lamberts is considered the minimum screen brightness for a completely light controlled room. Many people may disagree with that, and some have far less than that and find it acceptable, but that is the recommended min. The SMPTE and THX standard is 16 foot-Lamberts, and movie theaters usually produce between 12 to 22 fL of light at the screen. Television produces 35 fL or more depending if it's standard definition TV or HDTV.

So if you are less than 12 fL at the screen, that means you either should think about
  • A brighter projector
  • A smaller screen
  • Higher gain
For those that already purchased a projector, option 1 on the list is out of the question. That leaves a smaller screen or higher gain.

Gain is tricky. Some people guess at gain based on comparisons to other materials. This could be dead on accurate, but it certainly isn't reliable. Even commercial companies are sometimes guilty of using testing methods that do not adhere to industry standards and as such they may list 'custom' gains that are unrealistic. One company lists a gain of 1.8 for their CRT White, however when it was formally tested and reviewed, it was not as bright as a StudioTek 130 which has a gain of 1.3. The estimated gain was placed at 1.0 when the company stated it was 1.8.

Gain can bring the fL up to the level needed for a good sharp and vivid image, but many times people get caught up in the numbers. Higher gain is not always better. When gain goes up, the viewing cone goes down. Viewing Cone is the angle at which the screen brightness drops off dramatically from the on axis image. This cannot be avoided, as gain goes up viewing cone goes down, period.

Gain is a measurement of the reflectivity of any screen or projection surface. The gain number represents a ratio of the light that is reflected from the screen as compared to the light reflected from a magnesium oxide reference source. So a screen rated with a gain of 1.0 will reflect the same amount of light as a magnesium oxide reference, and a screen rated at a gain of 1.5 will reflect 50% more than the reference source. This does not mean light is being produced. There can never be more light than what the projector itself creates, and from the instant it leaves the bulb, the energy starts to decrease.

How this works is a 1.0 gain screen is referred to as a unity gain screen. This type of screen has an even amount of light dispersion across the entire surface of the screen and will look just as bright off axis as on axis. Once the gain increases, the light has to come from somewhere and in essence it comes from the off angle reflected light. Since more light is being focused and returned to the on axis viewing position, the off axis angles become dimmer. For the most part this is not a big issue since people normally do not sit at that far of an angle to a screen, but in certain venues such as a church, auditorium, or a bar, there usually are extreme viewing angles present. The angle at which the gain reading drops to 50% of the peak value is known as the Half Gain Viewing Angle. A person viewing the screen from this angle will see an image half as bright as the person seated at the center position.

A high gain screen does not typically reflect red, green, and blue equally. This can produce color shifts in the image that are very noticeable when the screen is viewed from different angles.


Ideally for Home Theater use, the gain is normally between 1.0 to 1.8. That isn't a set rule though and some may prefer a brighter image, but the brighter the image is, the more eye fatigue that occurs. There will be a point that even a two hour movie can induce a headache from strained eyes caused by a screen being too bright.
Also something to note about gain is when it goes up, aside from a reduced viewing cone, typically black level performance goes down and white level performance goes up.

Too much surface gain and you introduce specular gain, which almost always results in hot spotting or other image related issues. This really is only a problem with darker shades. An N9 or N8.5 are pretty safe and N9 isn't as susceptible to specular gain like a darker shade is.

So the base does play a factor in all of this, and as a foundation, the better balanced the base is the better the overall screen will be. Neutrals are also more efficient as reflecting light evenly and without shifting the colors. You could review two screens similar in shade, one being neutral and the other an unbalanced gray and without any top coating I guarantee the neutral screen will look brighter.

Good luck with the rest of your project and I hope in the end all turns out well for you. All that matters really is if you are happy in the end. :)
 

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12th,

I paged through the manuals for both of your cameras. There's no way to do a manual white balance on either of them. So basically just take a shot with the flash off in auto mode. From there we may be able to determine the best way to setup up your camera for screen shots. If I can't figure it out I'll give a shout out to JimP who's helped me out immensely in the understanding of color balancing a shot.

Sounds like you may have wanted to paint a substrate then, huh? Major bummer! Let us know what we can do to help!

mech
 

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12th man if you think there is too much texture and a paintable substrate isn't an option, check into liner paper. You will get smooth surface with that for sure.

It means starting over, but if you have to do that then you have to. For now though like I said, finish up with any additional recommended coatings and let it cure, then check it out.

I am getting ready for my screen reviews (when my daughter goes back to PA) and one of the things I will be testing and reviewing is a sprayer. If you can use a spray can and get a smooth even finish with no runs, this may be ideal for some people.

Rolling though still is a very viable application method and really isn't that hard to do without roller marks or excessive texture. The quality of paint though has a lot to do with that too. Cheap paints are loaded with lots of clay and don't roll or cover as well.
 

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And if you really want to know what I'd do....

I'd save the rest of what you have and then head on down to a True Value hardware store and have them mix you up either a Winter Mist or a Winter Mountain. Winter Mountain being the darker of the two and nearer to N8. Just pick up a quart, it'd be cheap (less than $20) and you can use the Wagner sprayer you just bought. Save that other stuff for some other time. You have young kids to and they will more than likely cause trouble with your screen...

mech
 

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Less than $10 :p

I color matched a certain $2000 screen and a quart was $9 and some change. :)
 

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Discussion Starter #49
Sounds like you may have wanted to paint a substrate then, huh? Major bummer! Let us know what we can do to help!
No doubt (in hindsight). I just never expected the wall texture to be an issue since I had never seen it shooting to my basic beige wall or even after rolling two coats of primer. i now realize that any high contrast paint is going to accentuate texture, blemishes, etc. Lesson learned.

With the size screen I am shooting for (120-126") the choice of substrates seemed pretty slim. Now I need to look in to that again and see what might work. For obvious reasons I find myself again wondering about a 122" DW or FG. :wits-end:
 

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With the size screen I am shooting for (120-126") the choice of substrates seemed pretty slim. Now I need to look in to that again and see what might work. For obvious reasons I find myself again wondering about a 122" DW or FG. :wits-end:
Go with the Winter Mist. True Value - $9 - one quart. You leave now you may be watching tonight! Get the latex flat obviously! :bigsmile:

mech
 

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I tend to agree with mechman. Get a quick fix in place to buy some time and rethink your situation. IfTrue Value is available that's great. If not then go to Home Depot and get some Behr UPW Flat-Enamel #1850. It can be easily rolled or sprayed on.

Your comment about texture and high contrast paint has one major flaw in it. It is the gain and viewing cone that cause wall texture or blemishes to be more visible. I'm not sure there is any such thing as a high contrast paint, but it does sound good doesn't it.

MississippiMan once mentioned that a sub-contractor mixed down some drywall compound with water and rolled it on a large screen area. He then sanded down the whole screen area to get a very smooth flat surface. I have found cheep chalky primer can be used in a similar way.

One thing for sure, one way or another we will get you setup without breaking the bank or your back. :T
 

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Discussion Starter #52
Thanks Tiddler. If availability is not an issue is the True Value Winter Mist the best option? I assume I would need to prime again since their are 6 sprayed and 1 rolled coat of SF on the wall right now?

With the time, money & effort I have invested in this project it only makes sense to take the advice I have been given by MM. I will roll two farily thick coats of the SF mix (as thick as it can be considering it has been thinned for spraying) and then if there is enough left, spray a final coat. If the texture is still there, that's it for me.

One of the things I will consider in the coming days is compromising my desire to have decent ambient light performance and seek an easy dark room solution. That gets back to the advice Wbassett gave me in the beginning to treat the problem at the source (windows) instead of at the screen. So if I want daylight viewing for Sunday afternoon football, etc. I will have to come up with a way to better control the light coming in. Just something to consider.
 

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12th man, I honestly feel you can get excellent ambient performance as well as overall performance with OTS and Todds Tints. It was your screen size, lumens and room setting as to why I made the recommendations I did.

I have a screen up right now that fairs more than well against a much more expensive commercial screen (as in several thousand dollars for the same size screen) and ambient performance is almost beyond reproach.

Winter Mist is the most D65 neutral paint I have seen and tested, OTS, custom mixes/tints, or commercial.

I still recommend right now that you do what you have planned and use the SF and then if you're not happy rethink things. You already have it up, so why not give it best effort and see if you can get it fixed and working to your liking. If not, don't be afraid to ask for recomendations.

I'm sorry to hear that your first stab at DIY wasn't the greatest experience, but think of it like this- you could have spent a lot of money on a commercial screen and ended up unhappy with it, and worse, maybe even stuck with it as far as money spent.
 

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I agree that you should follow through with MM's directions. I have no basis for comparison to the TV Winter Mist. I do know that the more neutral the gray the better it works. Surprisingly so. Wbassett's Gray Screen is a good example of how well a matte neutral gray can perform in ambient light conditions.

Did MM not suggest you give the screen a light sanding with a wet sanding sponge? That has been his recommendation in the past when texture was a problem. I could see sanding down the texture and then applying some rolled or sprayed coats may improve the surface. Good luck and keep us posted, we are interested and also learning from your experiences.
 

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Discussion Starter #55
My biggest mistake was not addressing the texture up front. I started out rolling 2 coats of primer and then did only a light sanding followed by a sprayed third coat. I thought that the coats of primer would be sufficient since I had not had problems with the texture before. I know, a naive rookie mistake!

So his correcting advice was to roll 2 fairly thick coats of the remaining SF mix, sand lightly and then spray a third coat if I have enough paint left. Well, after rolling the two thick (or as thick as I can get given the mix has been thinned for spraying) it is clear that the texture problem is NOT going to go away. So the last suggestion had made was like what Tiddler mentioned earlier -- thinning drywall compound, sanding and starting from scratch with 3 primer coats + 7-8 more SF coats. No thanks. I tried but need to go in a different direction.

So as to the earlier question I had -- I assume I will definitely need to prime again no matter what painted application I go with? Probably a good place to get back to anyway -- a matte white screen so further evaluation can be done before picking the next step.

Thanks for your help guys -- it is most appreciated
 

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12th,

With your Nikon, Go to Scene Mode and Close Up. Take some pictures of the wall irregularities for us. Not to mention we'd also like to see some close ups of this paint! :bigsmile: You can get as close as 1.6" according to the manual - as long as you are zoomed out all the way. Maybe take a screen shot or two with some ambient light as well...

mech
 

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Discussion Starter #59
I'll try to get some screen shots tonight or tomorrow before I start over with Kilz2. Mech, I'll let you check them out and provide some feedback before I post publicly. Thanks for your help!
 

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Discussion Starter #60
I want to make something clear as you guys continue to provide valued insight.

My unsuccessful first attempt at a DIY screen prompted some rethinking of my ultimate objective and preferences for this project. I have concluded that if there are trade offs to be made in whatever option I try next, I would like to favor the side of dark room performance and "pop" over ambient performance, black levels, etc. That is not to say I value those things any less but I do need to be mindful of the fact that we primarily use the projector at night and that's what I would choose to optimize for even if it means some sacrifice in other areas.

That said, how does Winter Mist do in a dark environment? After what I have been through I am obviously interested in OTS and other simple applications if the results are there. I have also read about an UPW with poly topcoat(s). Any thoughts on that?

Thanks guys for all your input. :clap:
 
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