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garyfritz
Joined: 08 Apr 2006
Posts: 12088
Location: Fort Collins, CO
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| Posted: Wed Nov 26, 2008 11:18 pm Post subject: |
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No, I don't think the blue hits a hard saturation line. Like I said, I believe the slope changes but the blue still keeps going up slowly. So IF you drove your blue hard enough, and your scaler was able to compensate for the resulting very nonlinear response curve, then it might work OK. Gary's experience indicates it can. He was running at very low contrast so he probably had a lot of headroom to overdrive the blue.
So I assume the way you'd do this is: set your blue Gain to get proper 6500K color temp **at 100IRE**. This will cause a huge blue hump in the midrange. Then you use the scaler to pull back the blue in the midrange, and voila: flat grayscale with no defocus. But it does depend on the ability to drive the blue hard enough to match the R/G levels at 100IRE, at a contrast level that provides the light levels you need.
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stefuel
Joined: 07 Mar 2006
Posts: 3353
Location: Green Harbor MA USA
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| Posted: Wed Nov 26, 2008 11:27 pm Post subject: |
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I couldn't resist with all the talk about expensive projectors and scalers. This is a screen shot on a 100" diag screen. It is std def scaled to 1080P from the armpit of all scalers (TAW Rock+SDI) and projected by the butt end of all projectors (AmPro 4600HD). The image was provided by a SDI modded DVD player.
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_________________
Chip
A Barco is only a AmPro with training wheels
Card carrying member of the AVS chain gang.
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Zebu Fellenz
Joined: 21 Dec 2006
Posts: 2567
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| Posted: Wed Nov 26, 2008 11:36 pm Post subject: |
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Chip,
That screenshot looks really bright, is that how it really looks or is the camera doing it? 100" Diag also seems small for a 9" machine, is there a reason you went with that size?
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Gary M.
Guest
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| Posted: Thu Nov 27, 2008 12:20 am Post subject: |
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| Mark_A_W wrote: | | Gary M. wrote: | | Mark_A_W wrote: | You can't compensate for true tube saturation by fiddling with the gamma curve.
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I don't understand?
you can correct the lack of blue at the high-end with a scaler and you can correct the middle blue hump with a scaler as well, all while having the sharpest blue with no defocusing, how do you mean you can't compensate?
this is hard on your blue tube yes, but it works just fine
here is the blue from my 1352 after 2.5 years, I used no blue defocus and boosted blue at the scaler end
-Gary |
You can only do so much Gary.
As Garyfritz said, once the blue hits the limit, it's difficult to eek much more out of it.
Fiddling with the gamma curve on a focused blue is really reducing the blue output in the middle, and then you are matching the red and blue to that. You are reducing your total output to match the limit set by the blue.
You can't push the high end of the blue higher, because it can't keep up - it's saturated.
If you defocus the blue, it will then keep up, and your output is then limited by the red and green, and is the max you can get from your projector.
It's all about personal choice - you chooses your compromises.
With a 9" Barco you will have plenty of light to sacrifice. |
thanks Mark, glad to hear that with the Barco, I had thought that should be the case, nice 
-Gary
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Gary M.
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| Posted: Thu Nov 27, 2008 12:25 am Post subject: |
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| Ohmess wrote: | I have a question. I own a Lumagen HDP, and from what I am reading here only use a fraction of its capability. My projector is in pieces, but will be back together soon, with a bunch of mods, 9" tubes and new lenses.
Where is a good place to learn how to use my Lumagen better? |
the Lumagen has most of the goodies in the service menu, go over to the Lumagen forums (official site)
you can do a heck of alot of things with that puppy, things only DVDO users dream of, mainly a greyscale from 0 to 100 IREs that is ruler flat, I mean 99% perfect(if you have equipment that can read well down low), on top of that select a couple gamma points down low and boost them to exactly where you wish
CRTs with color correction are very very close to specs, what little they are off can be corrected with the CMS on the HDP, color decoding at the source level is sometimes screwed up, again no problem on the HDP, separate hue and sat for red, blue and green
-Gary
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Gary M.
Guest
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| Posted: Thu Nov 27, 2008 12:26 am Post subject: |
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| stefuel wrote: | | I couldn't resist with all the talk about expensive projectors and scalers. This is a screen shot on a 100" diag screen. It is std def scaled to 1080P from the armpit of all scalers (TAW Rock+SDI) and projected by the butt end of all projectors (AmPro 4600HD). The image was provided by a SDI modded DVD player. |
dude you don't have to convince me that the Ampro 4600 has a killer image, I think that is obvious
post some big screenies for us 
-Gary
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AnalogRocks
Forum Moderator
Joined: 08 Mar 2006
Posts: 26706
Location: Toronto, Ontario, Canada
TV/Projector: Sony 1252Q, AMPRO 4000G
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| Posted: Thu Nov 27, 2008 3:17 am Post subject: |
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| stefuel wrote: | | I couldn't resist with all the talk about expensive projectors and scalers. This is a screen shot on a 100" diag screen. It is std def scaled to 1080P from the armpit of all scalers (TAW Rock+SDI) and projected by the butt end of all projectors (AmPro 4600HD). The image was provided by a SDI modded DVD player. |
No that's just the lower intestine. I think I got the butt end of the stick. 
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