CurtPalme.com Home Theater Forum

bpb · Joined: 01 Apr 2007 Posts: 57 Location: denmark

As written in the subject, i'm interested in knowing how your HT measures in foot lambert with what screensize and if your room is the batcave, semi dark or. and offcourse if you think the lambert you have is enoughf for you or its lacking.

oh okay. I haven't made my question clear... thx standard states 12 to 16 foot lambert, fair enought that much I understand.

Since the thx standard states a required foot lambert there must be a standard protocol to measure/calculate it.

but how is it suppose to be measured, Meaning with what imput color, 100 ire, all white or?

In my case its has to be calculated from the brochure specs as i don't have the equipment to measure it.

my brochure has 4 different lumens measures, 160lumens for 64khz 50hz at 6500, 130 lumens for 15khz 60hz at 6500, 200 lumens at 6500 in all white and 800 lumens at peak.

if calculated which lumens measure should I use, all whites 200 lumens or the 160 lumens.

Basically i'm trying to figure out how much lambert the rest of you crt lovers have and if its enoughf for your room configuration.
That way i can use your experience about lamberts and roomcolor, to make the right decision on what do with my new ht room, can i go larger with my d50 if i get a higher screen, or should i change pj to do larger images and would i wont a higher gain screen if a bought a 1209.

my Ht's was light to medium gray with a large black drape covering a 10x5 foot window, offwhite ceiling. i could have used both more lamberts and a darker room(soon doing a new ht room where it hopefully will be darker and with a higher gain screen)

Input Units
Screen Aspect Ratio 1,78
Screen Size 63 inches wide
Screen Gain 1,1 gain
Projector Brightness 160 ANSI lumens
Horizontal Resolution 1280 pixels
Vertical Resolution 1024 pixels
Actual Seating Distance (first row) 69,0 inches
Actual Seating Distance (back row)

Screen Dimensions
Screen Diagonal 72,3 inches
Screen Width 63,0 inches
Screen Height 35,4 inches

Field of View Width (first row center) 49,1 degrees
Field of View Width back row center)
Screen Brightness1 (projectors only) 10,3 foot-Lamberts

I used this fore calculating.

http://www.carltonbale.com/ht/calculator/theater_calculator_v4.0.xls

best regards

panduro

**AnalogRocks** · Posted: Sat Apr 11, 2009 8:30 pm Post subject:

Which projector?

bpb · Joined: 01 Apr 2007 Posts: 57 Location: denmark

Mine is a Sony d50(fore the time being).

Its whatever pj you are using with what size screen i want to know about.
im more interested in the foot lambert mesurements than with which pj its done with!

best regards

panduro

ecrabb · Posted: Sun Apr 12, 2009 12:09 am Post subject:

G70
1.78 96"x54" (110" diag)
~1.24 gain WilsonArt Designer White

Front row center viewing angle - 50º
Back row center viewing angle - 31.5º

Measured ~12fL on DVE: HD Basics 100 IRE window

Fully light-controlled room, dark walls. 1920x1080p, HD Fury 1, low-level gamma boost.

I love the brightness. I've never once felt like I wished I had a brighter image. Full fade to blacks are awesome.

SC

bpb · Joined: 01 Apr 2007 Posts: 57 Location: denmark

Hi ecrabb

100 IRE window, you lost me there;)

if i put in your numbers in the calculator with lumen numbers from http://www.curtpalme.com/docs/SonyG70_Brochure.pdf

i cant get yuur footlamberts up too 12lamberts, with the all white 320lumens i get 11,1lamberts, with 240 lumens i get 8,3 lamberts, 200 lumens i get 6,9lamberts.

is the all white number the one i should us or is the calculator somewhate lacking precision?

thanks for your answer

panduro

dturco · Posted: Sun Apr 12, 2009 2:38 pm Post subject:

Since your online I Will try to answer. I believe the 100 ire is a test pattern from the projector to put out peak white light from the P/J.

But I am not to sure as I have not pick up my Marquee yet.

I am sure others will answer better later.

bpb · Joined: 01 Apr 2007 Posts: 57 Location: denmark

oh okay. I haven't made my question clear... thx standard states 12 to 16 foot lambert, fair enought that much I understand.

Since the thx standard states a required foot lambert there must be a standard protocol to measure/calculate it.

but how is it suppose to be measured, Meaning with what imput color, 100 ire, all white or?

In my case its has to be calculated from the brochure specs as i don't have the equipment to measure it.

my brochure has 4 different lumens measures, 160lumens for 64khz 50hz at 6500, 130 lumens for 15khz 60hz at 6500, 200 lumens at 6500 in all white and 800 lumens at peak.

if calculated which lumens measure should I use, all whites 200 lumens or the 160 lumens.

Basically i'm trying to figure out how much lambert the rest of you crt lovers have and if its enoughf for your room configuration.
That way i can use your experience about lamberts and roomcolor, to make the right decision on what do with my new ht room, can i go larger with my d50 if i get a higher screen, or should i change pj to do larger images and would i wont a higher gain screen if a bought a 1209.

best regards

panduro

dturco · Posted: Sun Apr 12, 2009 3:55 pm Post subject:

I sorry I can not help. I am a noob myself.

But form my research the theoretical measuring you are trying for will not work.[IMO] the age of the p/j, tube wear, brightness settings, screen gains etc, are not constants.

It seems your are trying to get a consensus from the forum, which I would like to see also.

A poll might work for this but I do not know how to start one. Yet.

**AnalogRocks** · Posted: Sun Apr 12, 2009 4:02 pm Post subject:

bpb · Joined: 01 Apr 2007 Posts: 57 Location: denmark

I dont think ill ever stop being a "newbee" in the crt section, im better at sound so im not completely lost Laughing

But from my research the theoretical measuring you are trying for will not work.[IMO] the age of the p/j, tube wear, brightness settings, screen gains etc, are not constants.

Im aware of all these factors, but should still be possible to get some what near to the actual mesurement when calculating.

It seems your are trying to get a consensus from the forum, which I would like to see also.
correct Very Happy

AR running a d50 at 110" Shocked

thats like 90 inches wide? but youre running in a dark room it probably shows a better picture than my 63 wide 16/9 in a not so dark room.

best regards

panduro

**AnalogRocks** · Posted: Sun Apr 12, 2009 4:32 pm Post subject:

No actually the room it's in is all white with light colored curtains. The screen was what poped up on the forum.

bpb · Joined: 01 Apr 2007 Posts: 57 Location: denmark

how many crt setups are u running, ampro, sony 1252 and a d50. in different rooms?

my screen use to be a 100" wide motor screen i used with and lcd pj before i got my d50 and went nuts with a knife Evil or Very Mad

but it only a gain 1,0 thats the figure that the "factor" provided, so maybe lower.

best regards

**AnalogRocks** · Posted: Sun Apr 12, 2009 4:43 pm Post subject:

bpb · Joined: 01 Apr 2007 Posts: 57 Location: denmark

nice gr, my would throw it out the window if she could get i down from the ceiling Embarassed

oh well she go the same way if she succede Twisted Evil

**AnalogRocks** · Posted: Sun Apr 12, 2009 5:09 pm Post subject:

Well it's funny about my G/F she didn't want it, didn't need it. She said "Why would I want THAT?!"

The week after I set it up for her she had a party with her friends to watch American Idol. Laughing

**kal** · Posted: Mon Apr 13, 2009 12:03 am Post subject:

How to properly measure foot lamberts is covered in my Greyscale & Colour Calibration Guide. It's pretty much the first step. See: https://www.curtpalme.com/forum_archived/viewtopic.php@t=10457.html

I get 13.8 ftL on my 54x96" screen of approx 1.1-1.2 gain. Room is light controlled and fairly dark.

Frequency of the projector (ie: resolution) has nothing do to with foot lamberts. I don't see the relation.

Kal

**AnalogRocks** · Posted: Mon Apr 13, 2009 4:18 am Post subject:

**kal** · Posted: Mon Apr 13, 2009 1:37 pm Post subject:

raster gaps could be the reason, but I don't think it'll make that much of a difference.

Kal

stefuel · Posted: Tue Apr 14, 2009 11:22 am Post subject:

Technically speaking, the higher the scan rate, the brighter the image. Think of it this way, Lets say you put up a 100 IRE full screen pattern with a scan rate of 100 lines and the same pattern of 1080 lines. Which one would cast more light on the screen. The increased resolution theory stops when you reach a point where the scanlines touch as there is no longer black spaces between the lines.

ecrabb · Posted: Tue Apr 14, 2009 3:33 pm Post subject:

Yes, raster gaps are the reason, but since it's been about 5 years since anybody wasn't using at least a doubler, that discussion is pretty much moot... As has already been mentioned, at pretty much any HD resolution we'd all be using nowadays, there will be no measurable differences in brightness.