[Greg_R]

... repost since HTPC forum didn't get any results ...


I'm using TT2.0 and the gamma is _way_ off. I know how to make the adjustment (in powerstrip). Should I use some of the basic contrast and brightness patterns to set the gamma or are there some gamma specific patterns that I should use? (CRT display)

 

[BobL]

Hi Greg,


Some digital displays have the ability to adjust the gamma curve. I haven't seen it too much in CRTs'. It is usually the digital displays trying to imitate the gamma inherent in CRT's phosphors. I'm not sure if your PJ has the ability to adjust gamma. Below is some instructions from Guy Kuo. There is also a gamma pattern on AVIA.


Bob




"If you are actually serious about getting the gamma of a display to match the behavior of a standard display, you need to do the following.


1. Select the gamma setting to be examined.


2. Set black and white levels correctly


3. Measure the light output of the display as you feed it a series of grayscale windows.


4. Plot light output (y axis) vs IRE Level (x axis) to create the display's gamma curve.


A display with CRT like (standard) gamma curve will have an exponential shape which is approximately


light output = k * ((IRE - 7.5) /92.5 * 100)^2.35


The gamma setting of the display which best objectively matches that curve is the one which makes the display mimic the behavior of monitors used during the mastering process. You are free to use other shaped gamma curves, but realize you are then altering the image rather than simply trying to faithfully recreate it."

 

[Greg_R]

Ahh. So there is no method of eyeballing it (like brightness and contrast).


The Ehome8500 doesn't have a gamma adjustment. Unfortunately, when using TT2.0 the gamma setting appears to be off (extremely dim). This could be a video card issue or HTPC issue but the bottom line is that I need to boost the gamma significantly in powerstrip. Windows desktop is fine... it's just the TT2.0 overlay.

 

[pwentz3l]

You can adjust Gamma in TT2, then your adjusment will not affect any other applications running at that resolution.

 

[Phil Smith]

I adjust my HTPC's video card gamma. My 9700 Pro's gamma setting isn't sticky, so I have to reset it every time watch a DVD, which is maddening.


I've heard other suggest 1.45 or 1.7. Most of the time 1.2 works the best for me.

 

[techman707]

The Gamma adjustment in TT is only adjusting the overlay gamma adjustment of your display card driver. If you go into the control panel and select "display" and then advanced" and select overlay, you can either return the default settings or adjust it from there too.


There IS a pattern that has the gray boxes that you match up by eyeballing it to achieve the proper gamma (just like Adobe Photoshop uses), however, DVDs can vary widely and may need more than ONE setting, which is why TT remembers each DVD disks settings in a database.

 

[Erling]

Greg, what graphics card are you using ?


Apparantly, the default settings in TT2.0 aren't very good for ATI cards.


After some communication back and forth with TT's very helpful support team, they sent me the following suggestions for TT's video settings:


Brightness -5

Contrast +5

Hue 0

Saturation 23

Gamma 75


Those are the ones I'm using now with my Radeon 9600 Pro card, except for the saturation, which is way too high in my case. Ended up with it set to zero, with the aid of a setup DVD. The others appears spot on, and I now have lots of shadow detail again (completely gone with the default settings, and black was just black - not the infinitely varied nuances that CRT is capable of reproducing)


Cheers,

Erling

 

[BobL]

Hi Greg,


There is only the display pattern in AVIA for eyeballing it. But, I think that is more for just checking it. To use it as an adjustment tool would be pretty hard.


If you have a decent light meter like the ones made for photographers you could do it. And not as expensive as a color analyzer.


Bob

 

[techman707]

Quote:

Originally posted by BobL Hi Greg, There is only the display pattern in AVIA for eyeballing it. But, I think that is more for just checking it. To use it as an adjustment tool would be pretty hard. If you have a decent light meter like the ones made for photographers you could do it. And not as expensive as a color analyzer. Bob

A light meter or analyzer is not necessary for adjusting gamma on a pattern designed for it.