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Discussion Starter #1
I was just wondering if anyone has calibrated a projector. I have an optoma hd70 and got digital video essentials blue-ray from netflix, but i notice in my optoma menu there is red, blue, green, (controls) which i understand but there is other funtion which i do not. Under the color settings there are other ones which say red bias , green bias, and blue bias. In other words does anyone know what that means and will the calibration dvd do those color settings as well. here are some pics of my ghetto theater.
If someone has calibrated this projector or can explain the bias settings and any advice for my first video calibration that would be great.
Happy holidays





 

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Hi, I have the HD72 and I use the Avia home theater guide disc. The bias allows you to adjust each color individually as apposed to just increasing all colors at once. I am including a link to a review of your pj which is very informative and will explain it all in plain english, Good luck. http://www.projectorreviews.com/optoma/hd70/performance.php
 

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The bias allows you to adjust each color individually as apposed to just increasing all colors at once
i have for each settings the following:
settings to adjust red,green,blue but under each of them is the red bias, green bias, etc. Why is there two adjustments for the same color?
 

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It is just a way to fine tune and adjust the shade of the color when the regular color adjustment just increases or decreases the intensity of the color.
 

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Think of these as brightness and contrast for each color to adjust gray scale. The bias is like brightness, adjusting the darker areas, the other is for adjusting the brighter areas. They may interact.

These are used to adjust for a neutral gray scale so that there is no color from black through white when a b&w image or test patter is displayed.
 

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Discussion Starter #6
Think of these as brightness and contrast for each color to adjust gray scale
so will the digital video essentials disk calibrate everything? do i need any hardware to use the disk? i am just checking before the disk arrives and to find out that i need some piece of equipment.
 

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The disk does not calibrate anything. It just provides the test patterns and instructions on how to adjust your set, in general. You do it visually if you do not have a meter.
 

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The disk does not calibrate anything. It just provides the test patterns and instructions on how to adjust your set, in general. You do it visually if you do not have a meter.
Can a beginner do this? Will one side of the image be fixed so you can adjust the othe half?
 

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Everyone will have differing degrees of success. No, one side does not stay fixed. You are adjusting the entire image. DVE, Avia, and others are just sources for test patterns and information about how to use them.
 

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If calibration is performed visually, I think these programs help only in setting the black and white levels and somewhat help with gray scale. But for colors, hardware is necessary IMO.
 

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Well, maybe. Using the color filters provided with DVE and Avia, or if your unit has a blue only mode, you can get colors closer, if your display has the capability. Closer, in fact, than many who use inexpensive tristimulus colorimeters or meters with a spectral response that is not optimized for your display.
 

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Discussion Starter #12
ok i have tried again with the DVE disc and i kept messing it up.This is what i get from the disc.

1.brightness: Adjust so the blacker than blacker is just barely visable.(works on panasonic plasma but my optoma hd70 clips that signal). With the optoma i can just see two lines 4% and 2% above black. I move the control until the inside line (2%) is just barely visible.

2. contrast: I used the ramps to adjust for white but no matter how high i turn the contrast on the optoma and panasonic i can not get white to clip. So this is where i am stuck because i do not know when it is right. now this leads me to the color ( the part i can not get an answer to anywhere)

3. Color: I get it on the panasonic because it only has color/tint so i use the blue filter until the backround blends in together but leaves the black squares, but on the optoma it has color/tint and
green
red
blue
green bias
red bias
blue bias
so how do i use DVE to adjust all of the colors? Do i use each of the filters to adjust each color?(there is a blue,red,green filter that came with the disc). Or do i leave the other colors on default and just use the color/tint.
here are the screen shots of the menu system and maybe this will give someone a better idea what i am talking about.
http://www.projectorreviews.com/optoma/hd70/performance.php
if you scroll down you will see both the color/tint and under advanced are the gain/bias.
Any help or a web site that will explain this would be greatly appreciated. I have been looking for an explanation on many differnet web sites with no answers. I can not believe someone else has not asked this question. I just bought a new carada 92 inch brilliant white screen and want to calibrate it myself if i can. I will also give someone a draper custom 106 inch gray pull down if someone wants to come show me how to set up my display. I live in martinez ca. :wave:
p.s. i moved so i am re-setting it all up.
 

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I have this projector and here's my formula to 'simulate' the look of a Technicolor
film which will work on most pre-1970 features and some contemporary ones too.

Red 60 %
Blue 50%
Green 50%

Brightness 60 %
Contrast 70 %
Color saturation: increase it on a film by film basis to give vivid fleshtones
but not so saturated they look unatural.

Of course for sci-fi films, you'll have to re-adjust the brightness so the blacks of space
are pitch black but bright enough to see the stars.

Basically I make adjustments in the menu for every DVD I screen. I skip ahead and
try to find a night scene and a day scene and come up with the correct brightness
level overall. I do this with the AI filter off. Then I turn on the AI filter go back to
the beginning and play the disc.
 

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ok i have tried again with the DVE disc and i kept messing it up.This is what i get from the disc.

1.brightness: Adjust so the blacker than blacker is just barely visable.(works on panasonic plasma but my optoma hd70 clips that signal). With the optoma i can just see two lines 4% and 2% above black. I move the control until the inside line (2%) is just barely visible.

2. contrast: I used the ramps to adjust for white but no matter how high i turn the contrast on the optoma and panasonic i can not get white to clip. So this is where i am stuck because i do not know when it is right. now this leads me to the color ( the part i can not get an answer to anywhere)

3. Color: I get it on the panasonic because it only has color/tint so i use the blue filter until the backround blends in together but leaves the black squares, but on the optoma it has color/tint and
green
red
blue
green bias
red bias
blue bias
so how do i use DVE to adjust all of the colors? Do i use each of the filters to adjust each color?(there is a blue,red,green filter that came with the disc). Or do i leave the other colors on default and just use the color/tint.
here are the screen shots of the menu system and maybe this will give someone a better idea what i am talking about.
http://www.projectorreviews.com/optoma/hd70/performance.php
if you scroll down you will see both the color/tint and under advanced are the gain/bias.
Any help or a web site that will explain this would be greatly appreciated. I have been looking for an explanation on many differnet web sites with no answers. I can not believe someone else has not asked this question. I just bought a new carada 92 inch brilliant white screen and want to calibrate it myself if i can. I will also give someone a draper custom 106 inch gray pull down if someone wants to come show me how to set up my display. I live in martinez ca. :wave:
p.s. i moved so i am re-setting it all up.
The R,G,B, and Bias controls are for adjusting gray scale. This is done with gray scale patterns. You might improve the gray scale visually, but it requires a meter to really get it right. The color filters are for adjusting tint and color controls as described on the disc.

What do you feel that you are "messing up?"
 

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Discussion Starter #15
The R,G,B, and Bias controls are for adjusting gray scale. This is done with gray scale patterns. You might improve the gray scale visually, but it requires a meter to really get it right. The color filters are for adjusting tint and color controls as described on the disc.

What do you feel that you are "messing up?"
because i go back and forth from the main color and tint to the advanced controls and messing up the color. I quess i should just leave the advanced settings alone and just use the main color and tint. If you click the link you can see what i am saying. The whole reason i started this is because the projector has a red push and decreasing the main color washes out the rest of them, so i thought i could go into the red gain and bias and turn it down. This did not work because the other colors change as well. Sorry i am an audio guy and this is my first front projection. I just want to learn all i can about how they work is all. thank you for you input.
jason barnett
 

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You adjust bias and gain on R,G,& B to get good gray scale. Then you adjust color and tint. Without good gray scale, even a properly designed color decoder will not look right. Do not try to get color right with gray scale adjustments. You will likely chase your tail.
 

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Discussion Starter #17
You adjust bias and gain on R,G,& B to get good gray scale. Then you adjust color and tint. Without good gray scale, even a properly designed color decoder will not look right. Do not try to get color right with gray scale adjustments. You will likely chase your tail.
thank you that makes since? Which of the test patterns do you use to adjust grayscale? i do notice a red tint when i use the ramps pattern to adjust contrast. Should i try to adjust the red until the red is gone (all gray) from the ramps, and then once i see an even grayscale then adjust color and tint?
 
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