Which N do I choose for my screen?

**Richum** · **04-11-09, 10:52 AM**

I thought I would start this thread so as not to take other screen threads off track.

Guys,

Is there any analytical way to determine, based one's particular projector/lighting conditions, which to choose of these three neutral coatings, Black Widow N7.5, Scorpion N8 or Scorpion N8.5 (perhaps N9 at some point)?

Realizing that projector calibration is going to be essential to the final performance in any case, perhaps light meter reading under real world conditions as a starting point?

It could be that this is only be a matter of taste as long as you do not cause color shifts or create a detriment to the blacks/whites. Still I would prefer a bit more date as a starting point, a reason to choose one over the other.

All comments welcome.

**Harpmaker** · **04-11-09, 11:27 AM**

That is a GREAT question Richum, but to my knowledge, there has been little done to address it. While I doubt we will ever be able to determine the proper N shade for a HT screen from tests the average HT builder can do (it would be great to measure the color of 'ambient light' in the HT as well as the amount), I really do think we can do some things that can help make this more than a guess.

Since I purchased my $40 Lux meter and found out how nice it is to KNOW how much light my PJ was hitting my screen with, I have been of the opinion that EVERY serious HT owner should have one of these things. Not only does it let you know exactly how much light the PJ is hitting your screen with NOW, it will also let you keep tabs on how that light-level changes over time as the lamp ages or if you change the position of the PJ to go to a larger or smaller screen. Also, this meter will tell you how much ambient light you have hitting the screen under different viewing conditions (day-time, night-time, all-lights-out, Super Bowl party or game playing).

Just knowing how much PJ light is hitting your screen compared to how much ambient light will go a long way to determining the proper N shade for the screen.

My Lux meter

Ultimately though, it will probably come down to which you prefer, black blacks or white whites. Like most things in life, the best screen for a HT ends up being a compromise unless one has a dedicated 'bat cave' for movies only.

**clark17** · **04-11-09, 12:01 PM**

Quote:

Richum wrote:

Is there any analytical way to determine, based one's particular projector/lighting conditions, which to choose of these three neutral coatings, Black Widow N7.5, Scorpion N8 or Scorpion N8.5 (perhaps N9 at some point)?

I'm in the same boat as you are, as for N9 you can use Cream&Sugar by Harpmaker. Myself what I'll do most likely will be to add a tad of BW to my C&S#2 (to make it a little bit darker) to help my contrast. So it will be very light version of Scropion...

**Richum** · **04-11-09, 12:55 PM**

Thanks for your prompt response gentlemen.

Harpmaster, I also have a light meter it is the Mastech LX1330B Model and does the job quite well, so that is why I suggested its use.

Now that you've suggested measuring the ambient light that is found to be tolerable in a particular controllable setting and then measuring the lumen/lux/ft candles striking the screen it brings the following question to mind.

Could we arrive at a ratio of ambient to projector light and relate that to the Munsell Number we should shoot for? It looks like we have large jumps in range available with just 7.5 -->8.0 ---> 8.5 at this point in time. It seems that for now all we can assume is that we test one end of the scale to the other in three steps with no stop along the way.

It would be a neat trick if we could determine a fairly precise number, such as 8.3 for me, 7.9 for the next person. All this based on test results.

"I'm in the same boat as you are, as for N9 you can use Cream&Sugar by Harpmaker. Myself what I'll do most likely will be to add a tad of BW to my C&S#2 (to make it a little bit darker) to help my contrast. So it will be very light version of Scropion"

I understand but wouldn't it be nice to know just how much a "tad" is for any given situation! I have used the original BW and I am now projecting on to C&S (original) as well. I like the BW but I increased screen size when I purchased another projector and needed to whip out a screen post haste. Now that there appears to be a way to adjust the shade of B&W I am seriously considering painting yet another screen.

Of course, how dark or light should I go?

**wbassett** · **04-11-09, 01:39 PM**

Richum the short answer is no.

Quote:

Harpmaker wrote:

That is a GREAT question Richum, but to my knowledge, there has been little done to address it.

Harp the reason the short answer is no is not because little has been done to address it, in fact quite the opposite. For years now I have been trying to get people to think along the lines of Munsell gray shades and N values and finally they are. The problem with a flat out 'list' is that it also boils down to personal preference too.

Guys, say we had ten people that lived in a community where all the houses are laid out exactly alike (bland I know, but bear with me

). And all ten are using the exact same room as their HT room, and all ten even have the exact same projector. We very well could have ten different types of screens! They could range from DIY to commercial, and a variety of grays and white.

I personally am an advocate that even with a dedicated HT room with light control a light gray screen still has its benefits. Some people are deep dark inky black lovers while others want their whites to be as white as possible. Although it is true that a white screen will be the most accurate at displaying exatcly what the projector is producing, color wise a D65 neutral screen will also accurately display the colors the projector is producing. The difference is the white screen has better whites while the dark gray screen has better blacks... colors should remain accurate on both screens, that is as long as both screens are truly neutral. In the past gray screens were notorious for not having a good color balance, that isn't the case anymore.

Also some variables come into play, such as the room color. An all white/cream colored room with white ceiling, which is usually a living room (what I call a 'media room' or all purpose room) and not a dedicated HT room will actually create its own ambient light problems even at night and with all the lights off. I happen to think Designer White is an incredible screen, but there is a reason why I took mine down. My first projector was a 1700 Lumen Sharp LCD, and my current projector is a 2000 Lumen Panny AX200. The 1.3 gain of DW along with white ceiling and bright projectors- Well during dark scenes the room would be fairly dark, but for brightly lit scenes or bright movies, my room lit up like I had my lights on low to medium. It was bright enough that I could read a magazine with no trouble at all. When I switched to a gray screen that problem went away.

I was actually quite happy until I saw the first PFG panel and that's when I was totally sold on deep dark blacks!

Another variable is how a person is using their projector. I only use mine for big epic movies. Not even the current 'blockbuster of the week' always makes it up on the big screen. LOTR comes to mine, Kong... but not just epics... I like spinning the Bluray Bond flicks on the big screen, and a good western with the wide panning shots like you see on Quiggley Down Under or Dances with Wolves are made for the big screen. But again, that's my personal preference. Other's watch everything on their projector... and some not only watch TV, movies, and sporting events on the big screen... add in gaming consoles as well. The price of the latter is that it eats through bulb life ten fold faster than someone with viewing preferences like mine. I certainly am not putting that down, but I do recommend things differently to a person that is a gamer and watches a lot of TV on their projector.

Why? Well as I mentioned, bulb life. We all know as the bulb ages the image gets dimmer. A person can start off with a very dark screen and love it, but when their bulb age hits 70-75% of its life, often they find that now the image is too dim for their liking. By going with a lighter screen they can extend out their bulb life. I personally also recommend always having a spare bulb!

This is probably talked about more in the projector forum, but one recommendation is to not only have a spare bulb, but also to replace the bulb before it blows. I recommend when you hit 75% bulb life to replace the bulb. This is when the image really starts to become noticeable that it is getting dimmer. Why replace it now though when there is still a good 25% life left? A couple of reasons.

First it restores the image back to that nice bright image you started out with. Second... don't throw that old bulb out! Keep the old bulb as your emergency back up spare. It still has life left in it and if the new bulb blows, you have a back up until you get a replacement. Also this helps with expenses. It's not a fun thought of shelling out all that money on a new bulb, and let's face it... sometimes the household budget and finances are tight and a new spare has to wait. This way a person has a usable spare until they can afford a brand new spare. Once you get the new spare... then toss the old bulb. (But make sure to read the disposal instructions if any- Some bulbs can't just be thrown out.)

I digressed, but it was still on topic, and that is keeping the image bright even with a darker screen. I've known a couple people that go through a bulb a year, even less. I've also known someone that replaced their screen when the bulb started to dim, only to end up going back to the original screen once they got a new bulb... but they didn't have a spare on hand either. So when their bulb blew they had to wait until they could get a new one, and all that time they were without a projector- Another great reason to swap bulbs while the old one still has life left in it!

My point is that there are many many variables that come into play, and the biggest is personal preference. Some people just hate gray screens, and would never give up their pristine whites. And as mentioned, others love those dark blacks. I couldn't imagine watching 2001 without the space shots looking like a deep dark black nothingness!

This is why I advocate the 'interview' process. Only after totally assessing the room layout, personal preferences, what projector is being used (however I totally believe that the screen should come first and then the projector) can a true recommendation be made. This is actually how professional installers go about things.

The interview process is always done, but many times I see certain people end up recommending the same thing to everyone- so why they even waste time asking questions in the first place is baffling.

This is perhaps the single biggest advantage that DIY has over commercial screens- A person can quickly and inexpensively test out several DIY OTS painted screens and then decide based on what they like the best. Some may actually stick with the OTS method, other's will buy a commercial screen, while some will move on to a more advanced DIY method. All though will now know which shade they like the best. This is especially important when buying a commercial screen. Not all are returnable, and the companies that will take a screen back typically charges a hefy restocking fee.

Here's a tip... If you use OTS grays to pin down what shade suits you the best... Well for the most part whatever shade a person likes is the shade they should go with for a commercial or advanced DIY screen. Changing the gain, or the translucency or other screen items isn't going to make a person that likes an N9 gray necessarily now fall in love with an N8 screen, and vice versa. It can improve the image, but not necessarily the attributes that caused a person to fall in love with that shade in the first place.

It may seem like a lot of work and money, but it really isn't. Especially if you are painting your theater room in the first place. Take the time to prime the intended screen wall with a primer like Kilz2 and then calibrate and do your baseline evaluation. For around $25 a person can then audition two very good screen options... Winter Mountain and Winter Mist mixed up in Valspar's Signature Series Matte finish. This will allow a person to see a unity gain white screen for a reference and baseline (Kilz2), then a light N9 gray (Winter Mist) or a medium gray screen (Winter Mountain), and all for the price of a couple new release DVDs! Then decide what you like best.

**wbassett** · **04-11-09, 01:41 PM**

Guys sorry about the length of that last post, but it is a pretty important topic and can't just be answered or explain with a few quick sentences.

I do have a chart I am working on that breaks down recommended screen sizes and gray shades based on lumens, but it is only a max type chart. Meaning that's the maximum screen size, or maximum gray shade recommended. It doesn't mean that is what everyone should use, just means if you go beyond those specs expect the the image to start to suffer to some degree.

**doug goldberg** · **04-11-09, 01:52 PM**

Bill, Just think if you got paid by the word...

Personally I love the white on an N9+ screen but love the colors on the N*ish. What we need is a variable N screen to suit your needs that day. Can we work on that next guys. We just need a suitable electro-chromatic control system.

**mechman** · **04-11-09, 01:57 PM**

I agree with Bill!

It all boils down to personal preference. Do you like deep dark blacks? Do you like whiter whites? Do you like to have lights on? Many questions have to be answered before you can figure out what may suit you best.

**wbassett** · **04-11-09, 02:03 PM**

Gee... now I feel like a fool! I should probably edit it down.

**Harpmaker** · **04-11-09, 02:21 PM**

Quote:

Richum wrote:

Thanks for your prompt response gentlemen.

Harpmaster, I also have a light meter it is the Mastech LX1330B Model and does the job quite well, so that is why I suggested its use.

Harpmaster?

Oh, what the hey... I'll answer to about anything.

Yeah, I now remember; you got that meter some time ago. It would be interesting to know how your measured PJ light stacks up against what PJCentral's calculator predicts.

Quote:

Now that you've suggested measuring the ambient light that is found to be tolerable in a particular controllable setting and then measuring the lumen/lux/ft candles striking the screen it brings the following question to mind.

Could we arrive at a ratio of ambient to projector light and relate that to the Munsell Number we should shoot for?

I don't see why not, but this is only a guess on my part.

Quote:

It looks like we have large jumps in range available with just 7.5 -->8.0 ---> 8.5 at this point in time. It seems that for now all we can assume is that we test one end of the scale to the other in three steps with no stop along the way.

It would be a neat trick if we could determine a fairly precise number, such as 8.3 for me, 7.9 for the next person. All this based on test results.

In my personal testing so far, I'm seeing very little real need to have screens between the N0.5 (or Half-N) increments. While I can visually detect a N0.1 (or Tenth-N) change in side-by-side testing with Reference images (100% White Field and Color Bars), I don't think even a N0.25 (or Quarter-N) difference would really be detectable when viewing actual video content like sports or movies.

The matter of Tenth-N increments becomes a bit moot since the variation in paint color can be more than that from store to store or lot to lot. To get color and shade increments that precise we would have to go to artist paints for all ingredients except for the metallics. Believe me, we developers have thought, and are still thinking, about doing just that; but we would lose much of the KISS principle HTS screen paint formulae are based on by doing so since the user would have to tint the base themselves, which would require users to measure small amounts of artist colors - we really don't want that if it can be avoided. It's a pain in the posterior and every measurement is another chance for things to go wrong. Been there, done that.

So far we have found a way to use commercial base colors and tints to make our mixes and to add the metallics in whole-container increments so no measuring is required whatsoever. KISS baby! You gotta love it!

Quote:

"I'm in the same boat as you are, as for N9 you can use Cream&Sugar by Harpmaker. Myself what I'll do most likely will be to add a tad of BW to my C&S#2 (to make it a little bit darker) to help my contrast. So it will be very light version of Scropion"

I understand but wouldn't it be nice to know just how much a "tad" is for any given situation! I have used the original BW and I am now projecting on to C&S (original) as well. I like the BW but I increased screen size when I purchased another projector and needed to whip out a screen post haste. Now that there appears to be a way to adjust the shade of B&W I am seriously considering painting yet another screen.

Of course, how dark or light should I go?

The ratios for the various N shades are being looked into, but it takes time to do this. Believe me, we developers were recently fantasizing about being able to do this for a living so we would have more time to put into research and testing! As things stand, we have to do other things to put beans on the table and pay the mortgage.

**Harpmaker** · **04-11-09, 02:42 PM**

I was writing my response while Bill and mech were posting theirs.

Look at the last sentence in my first post. Yeah, I know it all boils down to what the user prefers, but I still think there should be a way to compare fL. at the screen under a 100% white field and then shut the PJ off and measure ambient light under various viewing conditions and come up with a real N value recommendation. By ambient light reading, I mean at the screen; this would take into account room color, sheen etc. The only thing I didn't address is that light readings should be taken of the walls in front of the viewers with the PJ on to measure how much light is reflecting off them from the screen itself (with a 100% white field).

This is quite geeky, and in the long run probably not necessary, but you never know...

**Richum** · **04-11-09, 03:28 PM**

Quote:

Harpmaker wrote:

I was writing my response while Bill and mech were posting theirs.

Look at the last sentence in my first post. Yeah, I know it all boils down to what the user prefers, but I still think there should be a way to compare fL. at the screen under a 100% white field and then shut the PJ off and measure ambient light under various viewing conditions and come up with a real N value recommendation. By ambient light reading, I mean at the screen; this would take into account room color, sheen etc. The only thing I didn't address is that light readings should be taken of the walls in front of the viewers with the PJ on to measure how much light is reflecting off them from the screen itself (with a 100% white field).

This is quite geeky, and in the long run probably not necessary, but you never know...

Let's state it this way.

I have a C&S screen that performs well in my medium gray room (screen is mounted on a flat black wall) with low ambient light, as to be expected it begins to wash out as I turn up two 50 watt variables in the back of the room. There is however a small range of increase in light that does not materially affect the performance of my C&S but makes the viewing of a remote control a bit easier.

For example if I were to come into the room after someone else had raised the lights to that level I probably would not take much note of it, while if I do it I see it as it happens. So perception is different in those two cases.

I may be wrong but I think C&S original is at N9, lets suppose now I am using the Scorpion 8.5 in the same room.

Could I expect the threshold of the light's effect to be higher before the perceivable washout of the N8.5 screen occurs?

**Harpmaker** · **04-11-09, 07:23 PM**

Quote:

Richum wrote:

Let's state it this way.

I have a C&S screen that performs well in my medium gray room (screen is mounted on a flat black wall) with low ambient light, as to be expected it begins to wash out as I turn up two 50 watt variables in the back of the room. There is however a small range of increase in light that does not materially affect the performance of my C&S but makes the viewing of a remote control a bit easier.

For example if I were to come into the room after someone else had raised the lights to that level I probably would not take much note of it, while if I do it I see it as it happens. So perception is different in those two cases.

I may be wrong but I think C&S original is at N9, lets suppose now I am using the Scorpion 8.5 in the same room.

Could I expect the threshold of the light's effect to be higher before the perceivable washout of the N8.5 screen occurs?

I used the wrong word in my last statement, it shouldn't be "necessary", but rather something akin to "needed".. even that doesn't really fit. I mean, people aren't doing this and they get along quite fine; but I know where you are coming from Richum.

Yes, an N8.5 mix should take more ambient light before you notice the screen image washing out; an N8 even more light; and so on as the N value of the screen gets higher and the screen gets darker.

A test you could do Richum, is to project a reference image (such as color bars or contrast bars) and then bring up the lights until you notice perceivable washout, then turn off or block the light from your PJ and take a reading of ambient light at your screen. You could compare this with the reading you get from a 100% white field image with no light on (except the PJ or course

); it might be better to take a reading of the same reference image and not the 100IRE image, but I don't know how you would do that.

I would suggest leaving the readings in Lux and not converting them to fL. because Lux is a more sensitive reading (there are over 10 Lux per fL.).

Do this for your various screens or test panels and see how much additional light the darker screens can take before you perceive washout. I know all this hinges on your perception, but it's a start. If such empirical testing looks like it might "go somewhere", a testing protocol could be developed where one would actually measure screen contrast changes to set a standard to measure by.

Or maybe I'm just totally nuts!

**Richum** · **04-11-09, 08:49 PM**

Quote:

A test you could do Richum, is to project a reference image (such as color bars or contrast bars) and then bring up the lights until you notice perceivable washout, then turn off or block the light from your PJ and take a reading of ambient light at your screen. You could compare this with the reading you get from a 100% white field image with no light on (except the PJ or course); it might be better to take a reading of the same reference image and not the 100IRE image, but I don't know how you would do that.

I will try this tomorrow and let you know what kind of readings I get in Lux. if nothing else we may be able to arrive at a general rule of thumb.

**Richum** · **04-12-09, 04:14 PM**

Harpmaker,

I did the testing you suggested in the following way;

Projected color bars and raised lighting until the first noticeable affect occurred, I will call this the threshold, then I took the following reading after turning off the projector:

1.4 Lux center of C&S screen

Turned projector back on and allowed 5 minutes for warm up, used the blank screen feature which on my projector displays bright white:

130 Lux Center of C&S screen

As can be seen very little light is required to effect screen washout.

I am considering spraying N7.5, 8.0, and 8.5 on a piece of blackout cloth placing it across my present screen and repeating the tests. It will probably be 6 weeks or more before I can accomplish it, I am starting into my busy season and spare time will be at a premium.

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