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kal
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Joined: 06 Mar 2006
Posts: 18114
Location: Ottawa, Canada
TV/Projector: JVC DLA-NZ7
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| Posted: Sat Apr 12, 2008 6:05 pm Post subject: Barco calls them G2/Gain/Cutoff - What about other brands? |
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I'm working on the "Step by Step guide to Greyscale Calibration" that I've promised.
EDIT: The GREYSCALE CALIBRATION FOR DUMMIES guide is now up for those that haven't seen it already!
Barco's use the following terms:
- G2 aka "Grid 2":For controlling at which point the tube lights up. Usually a pot inside the projector.
- Cutoff or Bias: The control used to adjust the amount of colour in the low IRE range. Like an individual brightness control for each colour. Some manufacturers call it 'Cutoff', others call it 'Bias'.
- 'Drive' or 'Gain': The control used to adjust the amount of colour mostly in the high IRE range. Like an individual contrast control for each colour. Some manufacturers call it 'Drive', others call it 'Gain'.
What about other manufacturers? What do they call the terms 1-3? I want to make it clear to others using Marquee, Sony, Ampro, NEC, etc.
Kal
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Last edited by kal on Wed Apr 30, 2008 7:43 pm; edited 3 times in total
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Tim in Phoenix
Joined: 21 Oct 2006
Posts: 4409
Location: Phoenix
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| Posted: Sat Apr 12, 2008 6:45 pm Post subject: |
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Hello
Marquees use G2 and Drive (gain), there is no cutoff control; is cutoff like gamma?
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stefuel
Joined: 07 Mar 2006
Posts: 3353
Location: Green Harbor MA USA
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| Posted: Sat Apr 12, 2008 8:12 pm Post subject: |
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AmPro calls it "running and not running" 
Actually "sub brightness and sub contrast"
That's why AmPros suck so bad. This is all they have.
Master contrast
Master brightness
G2 control
sub contrast
sub brightness
9 zone contrast modulation (optional) I have it.
gamma (optional) I have it.
What I don't have is up-gradeitis 
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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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AnalogRocks
Forum Moderator
Joined: 08 Mar 2006
Posts: 26706
Location: Toronto, Ontario, Canada
TV/Projector: Sony 1252Q, AMPRO 4000G
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| Posted: Sat Apr 12, 2008 9:58 pm Post subject: |
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| stefuel wrote: | AmPro calls it "running and not running"
Actually "sub brightness and sub contrast"
That's why AmPros suck so bad. This is all they have.
Master contrast
Master brightness
G2 control
sub contrast
sub brightness
9 zone contrast modulation (optional) I have it.
gamma (optional) I have it.
What I don't have is up-gradeitis |
LOL
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Tim in Phoenix
Joined: 21 Oct 2006
Posts: 4409
Location: Phoenix
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| Posted: Sat Apr 12, 2008 10:22 pm Post subject: |
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Hello
This is my procedure for Marquees from four years ago http://www.etechvideo.com/techtip1.htm I now use Brite at 44 for myself, other chassis may vary some.
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Ile
Joined: 09 Mar 2006
Posts: 1491
Location: Jyväskylä, Finland
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| Posted: Sat Apr 12, 2008 11:22 pm Post subject: Re: Barco calls them G2/Gain/Cutoff - What about other brand |
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| kal wrote: |
2. Cutoff = For controlling low IRE values - how fast a tube 'cuts off' into black. 3 menu settings. One for each colour.
3. Gain = Controls the high IRE values - how much light a tube puts out. 3 menu settings. One for each colour.[/b]
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I think green cut off and green gain is only available in newer s Barcos. (except 801s)
| Tim in Phoenix wrote: | | is cutoff like gamma? |
No, it's like individual brightness for R/G/B (or R/B in older Barcos) to adjust black end color balance from menu.
There is also cut off pots in neck boards...
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kal
Forum Administrator
Joined: 06 Mar 2006
Posts: 18114
Location: Ottawa, Canada
TV/Projector: JVC DLA-NZ7
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| Posted: Sun Apr 13, 2008 2:47 pm Post subject: Re: Barco calls them G2/Gain/Cutoff - What about other brand |
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| Ile wrote: | | kal wrote: |
2. Cutoff = For controlling low IRE values - how fast a tube 'cuts off' into black. 3 menu settings. One for each colour.
3. Gain = Controls the high IRE values - how much light a tube puts out. 3 menu settings. One for each colour.[/b]
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I think green cut off and green gain is only available in newer s Barcos. (except 801s) |
Nope, my old Barco 800 also had gains/cutoffs for setting greyscale.
So it seems that most call the lower end control "cutoff or bias" and the upper end control "gain or drive". I'll go with that.
I spent 8 hours writing the "Greyscale calibration for dummies" and it's still not done. Lots of work!
Kal
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kal
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Location: Ottawa, Canada
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kal
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Location: Ottawa, Canada
TV/Projector: JVC DLA-NZ7
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| Posted: Sun Apr 13, 2008 2:54 pm Post subject: |
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| Tim in Phoenix wrote: | Hello
Marquees use G2 and Drive (gain), there is no cutoff control; is cutoff like gamma?
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Cutoff is not gamma.
- Cutoff or Bias: The control used to adjust the amount of colour in the low IRE range. Like an individual brightness control for each colour. Some manufacturers call it 'Cutoff', others call it 'Bias'.
- 'Drive' or 'Gain': The control used to adjust the amount of colour mostly in the high IRE range. Like an individual contrast control for each colour. Some manufacturers call it 'Drive', others call it 'Gain'.
It sounds like on a Marquee the cutoff/bias control is called G2? (That's confusing).
Anyone here done greyscale on their Marquee using a colorimeter? (There HAS to be someone).
To everyone else: Some of you have given me the list of names of the controls in a certain brand but unless you tell me what the controls do this doesn't help me map this to either "cutoff/bias" or "drive/gain".
I'm assuming that there has to be at least ONE person around here with a Marquee, NEC, Ampro, Sony that has done greyscale calibration with a colorimeter that can tell me what the two controls are??
Kal
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garyfritz
Joined: 08 Apr 2006
Posts: 12088
Location: Fort Collins, CO
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| Posted: Sun Apr 13, 2008 3:36 pm Post subject: |
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| kal wrote: | | Anyone here done greyscale on their Marquee using a colorimeter? (There HAS to be someone). |
I have, but I haven't been running my Marquee for over a year, so it's hazy.
You've got it right -- the Marquee's controls are called G2 (bias/cutoff) and Drive (gain). You can get fairly close by eye using the internal stepped grayscale pattern, but a colorimeter definitely does a better job.
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ecrabb
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Joined: 13 Mar 2006
Posts: 15909
Location: Utah
TV/Projector: JVC RS40, Epson 5010
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| Posted: Sun Apr 13, 2008 3:53 pm Post subject: |
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Sony calls them W/B Bias and Gain.
Bias is cut-off (shadow) and Gain is drive (highlight).
SC
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Ile
Joined: 09 Mar 2006
Posts: 1491
Location: Jyväskylä, Finland
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| Posted: Sun Apr 13, 2008 7:14 pm Post subject: Re: Barco calls them G2/Gain/Cutoff - What about other brand |
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| kal wrote: | | Ile wrote: | | kal wrote: |
2. Cutoff = For controlling low IRE values - how fast a tube 'cuts off' into black. 3 menu settings. One for each colour.
3. Gain = Controls the high IRE values - how much light a tube puts out. 3 menu settings. One for each colour.[/b]
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I think green cut off and green gain is only available in newer s Barcos. (except 801s) |
Nope, my old Barco 800 also had gains/cutoffs for setting greyscale. |
My point was that older ones don't have those for green like new ones.
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kal
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garyfritz
Joined: 08 Apr 2006
Posts: 12088
Location: Fort Collins, CO
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| Posted: Mon Apr 14, 2008 2:32 am Post subject: |
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| kal wrote: | | For Electrohome,s what about the actual tube G2 level? Is there a different name for that? This is the actual bias voltage on the tube (Grid 2). |
Hmm, I'll let Tim or Dragan answer that one. As far as I know there's no remote-controlled way to adjust that, and I don't recall seeing any adjustments for it in the setup procedures either.
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Mark_A_W
Joined: 15 Mar 2006
Posts: 3068
Location: Sunny Melbourne Australia
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| Posted: Mon Apr 14, 2008 2:39 am Post subject: |
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Black Bias is just a fine tuning of G2.
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NEC calls it Kelvin W (white, for Gain) and B (black, for Bias).
There are any number of pots/controls involved in G2, so I'll not attempt to spell that out for a NEC 
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kal
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Location: Ottawa, Canada
TV/Projector: JVC DLA-NZ7
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| Posted: Mon Apr 14, 2008 3:23 am Post subject: |
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| garyfritz wrote: | | kal wrote: | | For Electrohome,s what about the actual tube G2 level? Is there a different name for that? This is the actual bias voltage on the tube (Grid 2). |
Hmm, I'll let Tim or Dragan answer that one. As far as I know there's no remote-controlled way to adjust that, and I don't recall seeing any adjustments for it in the setup procedures either. |
Correct - it's not usually done by remote.
In my procedure I'm going to mention that people should make sure that the tubes all 'turn on' at the same moment - this is something that in barco's you set with G2 pots inside the projector. I'm just trying to figure out what they're called in other models.
| Mark_A_W wrote: | Black Bias is just a fine tuning of G2.
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Correct!
| Quote: | | NEC calls it Kelvin W (white, for Gain) and B (black, for Bias). |
Sorry, what the actual NEC terms? "Kelvin W" and "Kelvin B"? (Been a while since I had an XG).
| Quote: | | There are any number of pots/controls involved in G2, so I'll not attempt to spell that out for a NEC |
That part I DO remember... What a nightmare.
Kal
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kschmit2
Joined: 09 Mar 2006
Posts: 1141
Location: Heidelberg, Germany
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| Posted: Mon Apr 14, 2008 7:03 am Post subject: |
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Kal,
The Kelvin/White Balance adjustments are either called W and B (PG series) or WHT and BLK (XG series).
W/WHT: while level adjustment | < decreases white level | > increases white level
B/BLK: black level adjustment | ˅ decreases black level | ˄ increases black level
Kai
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kal
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Location: Ottawa, Canada
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MikeEby
Joined: 24 Jun 2007
Posts: 5237
Location: Osceola, Indiana
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| Posted: Mon Apr 14, 2008 3:31 pm Post subject: |
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| kal wrote: | Thanks Kai. So in the PG and XG menus how exactly are they labelled ? They can't just have a menu item called ""W" and "B" do that? That seems kind of odd.
Kal |
On an XG remote hit Kelvin key>Enter passcode>kelvin key again to enter the White Balance adjustments then ctrl>R for red, ctrl>G for green and ctrl>B for Blue. Does that make sence? the menus are too slow. It's much faster to use the remote keys.
Mike
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kal
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Location: Ottawa, Canada
TV/Projector: JVC DLA-NZ7
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| Posted: Mon Apr 14, 2008 3:35 pm Post subject: |
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| MikeEby wrote: | | kal wrote: | Thanks Kai. So in the PG and XG menus how exactly are they labelled ? They can't just have a menu item called ""W" and "B" do that? That seems kind of odd.
Kal |
On an XG remote hit Kelvin key>Enter passcode>kelvin key again to enter the White Balance adjustments then ctrl>R for red, ctrl>G for green and ctrl>B for Blue. Does that make sence? the menus are too slow. It's much faster to use the remote keys.
Mike |
Yes, but that's for the advanced users. For the newbies I still want to describe what it's called in the menus so that they know how to at least find it as this'll be the first time most of them do this. I want it to be the simplest way to understand, not the simplest way to implement.
Kal
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