CurtPalme.com Home Theater Forum

tommo2 · Joined: 03 Jun 2006 Posts: 226 Location: Ireland

Hey, can I use my scaler test patterns?
I have a iScan HD and there is a test pattern generator which will display a grey window from 10IRE to 100IRE in 10 IRE steps.

The only problem I can see is that it is a quarter screen window, not 10% as you recommend.

Extract from the manual:

10-100 IRE
Gray Window
TP9 -
TP18
This sequence of patterns consists of a centered, quarter-screen gray window. The gray level varies from 10 IRE to 100 IRE
in 10 IRE steps.

Cheers for all this KAL. It is a very useful thread that i think everyone will benefit from.

**kal** · Posted: Fri Apr 18, 2008 5:29 pm Post subject:

**kal** · Posted: Fri Apr 18, 2008 5:30 pm Post subject:

WTS · Joined: 08 Mar 2006 Posts: 1276 Location: Calgary

Hi Kal,

Show me were it says that the 10% window is the standard for doing the grayscale on CRTs. Not that I don't believe you.

Nashou66 · Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY

TomHuffman also staes to use a 10% window over on the AVS calibration forum, you have to read down some but its in there.

http://www.avsforum.com/avs-vb/showthread.php?t=852536

And its also stated here:

http://geekwithfamily.com/2006/12/16/home-theater/howto-hcfr-free-video-projector-calibration-software/

This is actually i pretty good basic guide for grey scale using HCFR and the Syder2

Athanasios

**kal** · Posted: Sat Apr 19, 2008 12:03 am Post subject:

I'm not sure where I read the 10% window but I think most test discs use about a 10% window. With diigital projectors it doesn't matter that much as they put out a lot of light and it's always more or less the same amount no matter what the window size is.

CRT however will only put out about 1/2 the light at 100IRE for a full screen pattern as it will with a 10% window pattern. I tested it myself. I get just under 14 ftL with a 10% widow 100IRE pattern and only around 8 with a full screen 100IRE pattern which ! So if I calibrate using the full screen patterns I'm only calibrating for up to about 8 ft/L output I'm leaving the top 50 IRE uncalibrated! Example: If I watch a movie that has content with a bright white area for approx 10% of the screen and the rest of it is reasonably dark, I've never driven my tubes that bright during calibration so it'll be completely off.

The high end is usually where it suffers too - as blue drops off usually pretty drastically for CRTs.

Kal

WTS · Joined: 08 Mar 2006 Posts: 1276 Location: Calgary

Hi Kal,

What test disc has the 10% windows? I know AVIA does but I heard long ago that it's greyscale is tinted somewhat. DVE uses 100% and HCFR uses 100% windows.

Nashou66 · Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY

DVE Blu Ray has 10% windows i was playing around with it this morning, the window covers 10% of the screen area. Like kal said I tried useing the 100% window and i get a very low foot lambert reading compared to the 10% window.

WTS · Joined: 08 Mar 2006 Posts: 1276 Location: Calgary

Okay I don't have the new BR DVE disc.

Yes I meant 10% window.

Yes of course you'll get a brighter picture when you're only using 10% windows.

**kal** · Posted: Sat Apr 19, 2008 1:52 am Post subject:

The AVS HD Rec 709 disc also has 10% windows (10% of the window is varying shades from 0 to 100 IRE)

Kal

WTS · Joined: 08 Mar 2006 Posts: 1276 Location: Calgary

I guess the AVS BR version should have the same then.

**kal** · Posted: Sat Apr 19, 2008 2:33 am Post subject:

I've updated my procedure again. This time explaining how to take initial measurements with a sensor so that you have some sort of baseline to compare against.

Mort importantly, I walk through all of the graphs and explain what they mean, how they work, etc. Using my projector set to the 6500K default. You'll see (and I'll explain how) even the 6500K default is far from accurate.

See the 3d post in this thread. Link: http://www.curtpalme.com/forum/viewtopic.php?p=113347#113347

Kal

**kal** · Posted: Sat Apr 19, 2008 3:28 am Post subject:

Nashou66 · Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY

Kal, When I first press the Green arrow key to start taking continuous readings it asks to calibrate the sensor. If i press no it wont start reading, untill i claibrate it , this is where i have a question. How do i calibrate it? It says place the Eye one sensor on a planar surface, what does that entail actually? And is this only for the Eye One sensor? I assume it should be calibrated to a white source but how do i determine if that white source is actual the correct white?

Athanasios

WTS · Joined: 08 Mar 2006 Posts: 1276 Location: Calgary

Kal,

Can you post your HCFR *.chc file for your Cine8, I'd like to compare it to mine which I just did last night. Yes I used the ire windows this time, although I never had time to do one using the full window ire.

**kal** · Posted: Sat Apr 19, 2008 4:31 pm Post subject:

Nashou66 · Joined: 12 Jan 2007 Posts: 16171 Location: West Seneca NY

Ok I found some infor on the Display2LT probe from EYE ONE. I am waiting for some specific answers about the planar surface thing. But it does have to be calibrated : Apparently it needs to be put into a black box with not light comming in and an offset calibration needs to take place from the set up menu in HCFR for the probe.

ddrick from the AVS calibration thread:

WTS · Joined: 08 Mar 2006 Posts: 1276 Location: Calgary

Hi Kal,

Interesting how different your settings are. Are you pointing the probe at the projector or at the screen? I used the AVS BR test disc with the HCFR probe pointed at the screen, it was about 3/4" from the screen at an angle, I tried to attach at jpg pic of it but it is too big.

What cal file did you use, I used the NEC XG file, last time I used the NEC PG6 file, not if one is better than the other, although I will say the cal I just did does look very good.

I've attached my file, just change the ext from txt to chc.

tommo2 · Joined: 03 Jun 2006 Posts: 226 Location: Ireland

Hey KAL,
dont forget about including G2 setup before any grayscale calibration.

WTS · Joined: 08 Mar 2006 Posts: 1276 Location: Calgary

One thing I don't understand looking at my results is when I was doing the continuos measurement and setting the bias / gains the 3 colours were pretty much on top of each other all the way from 10 to 100 ire. But when I did the capture part of it(clicking the GO on the measures screen) and I compare the results it shows them off more than what the continous showed. When I did the capture part I let the crt/probe stablize on the new ire window for at least 80secs before I clicked for it to sample/read it. Just seems odd that it would show so much difference in the readings.