Wednesday, May 1, 2013

Is it possible to use a digital camera to calibrate the color balance of a TV?

Q. If I color balance the digital camera at daylight (6500K) will that allow me to properly calibrate my TV's color balance by taking pictures of a shade of gray on the TV screen using the digital camera?

A. Using a digital camera in place of a proper color measurement instrument will not work when it comes to any aspect of instrument-based display calibration. Instrument-based display calibration is intended to precisely set the colorimetric white-point at multiple—typically predetermined—gray-scale levels. The standard white-point reference target for a video display device is CIE D65 (which correlates to a color temperature of 6504 K,) within a margin of error—or CIELUV delta E (dE or ∆E)—of 6 or less across a range of gray-scale levels spanning from 20 IRE to 90 IRE and a ∆E of no more than 10 at the gray-scale extremes. (Note: some techs prefer to report ∆u´v´ color difference values in addition to or as an alternative to ∆E. Also, some calibration techs prefer to use much tighter margins of error.) A digital camera simply cannot accomplish this fundamental measurement necessary to calibrate a display device.

Proper colorimetric measurement devices can be obtained at a reasonable price. A very effective tristimulus colorimeter, which performs as well as some professional devices that cost several orders of magnitude more, is the i1Display 2 from X-Rite (formerly GretagMacbeth.)

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CIE Standard Illuminant D65 is the accepted worldwide industry standard white point reference for video displays including HDTVs. (Note: a CCT of 5400 K is the accepted industry standard for displays used in graphic arts applications.) For motion picture and video applications D65 should ALWAYS be the target calibration reference point to ensure accurate color reproduction not the derived CCT value of 6500 K.

In the field of colorimetry and color science 6500 K is referred to as a “Correlated Color Temperature” and is represented in two-dimensional color space, aka a CIE chromaticity diagram, by a straight LINE—specifically an “isotemperature line”—that transversally passes through a point on the Planckian (aka blackbody) locus. Any pair of chromaticity coordinates lying along the 6500 K isotemperature line, no matter their visual difference, will produce a corresponding CCT of approximately 6500 K (though only one pair of coordinates will be closest to the ideal D65 source point.)

D65, being a specific reference point and not a line, is a substantially more precise target—and is therefore preferred—for precision display calibration as opposed to a potentially infinite number coordinates along a line. Do-it-yourselfers and knowledgeable, well-trained display calibration technicians should be well aware of this very important fact.

######################## RESOURCES ########################

[PDF] Calibration – What Is WRONG With This Picture?
http://www.sencore.com/uploads/files/WhatIsWrong.pdf

“Picture Perfect: TV Calibration Demystified”
http://www.soundandvisionmag.com/features/2007/01/picture-perfect-tv-calibration-demystified

“Ten Steps to Set Up Your New HDTV Without a Calibration”
http://www.hdtvexpert.com/?p=259

Secrets of Home Theater and High Fidelity
– “CalMAN Calibration Bootcamp: A Crash Course in the Science of Calibration”
http://www.hometheaterhifi.com/technical-articles/898-spectracal-calibration-bootcamp-a-crash-course-in-the-science-of-calibration.html
– “Professional Display Calibration: What It Is and What It Means to Your Home Theater Experience”
http://www.hometheaterhifi.com/technical-articles/488-a-secrets-technical-article.html
– “DIY HDTV Calibration Software Overview: A Comparison of ColorHCFR, ChromaPure, and CalMAN”
http://www.hometheaterhifi.com/diy/813-diy-calibration-overview.html

CNET Video: “How to Calibrate Your TV”
http://reviews.cnet.com/Calibrate_your_TV/4660-12443_7-6534987.html

“How to Calibrate your HDTV with Avia-Digital Video Essentials and DVE”
http://www.ramelectronics.net/Video-calibration.ep

Avical’s DVE User-Level Video Calibration Tutorial
http://www.avical.com/articles/avicals_dve_user-level_video_calibration_tutorial.html

AWH - How to Calibrate a Television FAQ
http://myweb.accessus.net/~090/how2adj.html

Is D6487K too low of a color temperature for an LCD TV?
http://answers.yahoo.com/question/index?qid=20080324173810AAHkg1g

AV Science (AVS) Forum
– Display Calibration
http://www.avsforum.com/avs-vb/forumdisplay.php?f=139
– Display Calibration Archive (2005-01-01 through 2006-12-31)
http://archive2.avsforum.com/avs-vb/forumdisplay.php?f=139
– ISF Calibration Discussion and Information
http://www.avforums.com/forums/forumdisplay.php?f=311
– Basic Guide to Color Calibration using a CMS (updated and enhanced)
http://www.avsforum.com/avs-vb/showthread.php?t=852536&pp=60

Display Calibration Resources
http://docs.google.com/Doc?id=dhpmqnbb_4g8mtjzdf

TweakTV - Tutorials
http://www.tweaktv.com/tutorials/index.php

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Spears & Munsil
– High Definition Benchmark Blu-ray Edition
http://www.spearsandmunsil.com
– [PDF] High Definition Benchmark Blu-ray Edition User’s Guide
http://www.spearsandmunsil.com/pdf/UG_SM_HD_Benchmark.pdf

Joe Kane Productions
– Digital Video Essentials: HD Basics
http://www.videoessentials.com/DVE_HDBasics.php
– DVE Program Notes
http://www.videoessentials.com/program_notes.php

GetGray - Digital Video Calibration DVD Software (donationware)
http://www.calibrate.tv

AV Science (AVS) Forum
– New Calibration Disc (GetGray)
http://www.avsforum.com/avs-vb/showthread.php?t=586139&pp=60
– Calibration Meter Shootout
http://www.avsforum.com/avs-vb/showthread.php?t=958099&pp=60

X-Rite
– X-Rite Products
http://www.xrite.com/top_products.aspx
– [PDF] X-Rite i1 Monitor Solutions
http://www.xrite.com/documents/literature/en/985629_i1_Monitor_Solutions_en.pdf
 


Cannot adjust the poor picture quality on Samsung HDTV well?
Q. Samsung 55" 1080 LED, 120Hz Model No UN55EH6000

What do I need to know in order to adjust the poor picture quality of my Samsung HDTV? It is very difficult to adjust. Either it's is too bright, highlights are too bright, colors to vivid, picture has green blotches on it when it comes to the faces of white people.

Also the settings are too detailed. A person can adjust the gamma ray settings which I don't know anything about.

We just bought this TV a week ago

A. There is sometimes software in the new televisions like "MotionFlow" that try to enhance details, but this sometimes cause the "Soap Opera" effect - every scene looks like a overly lit soap opera.

Try to turn these enhancements off.

As Tex said - you need to be feeding that television a HD signal.

You should also do a rough calibration on any new television (They are set at the factory to ultra-bright Torch mode to be eye-catching if the unit is used for a floor display).

Get a Pixar movie on BluRay and go to the disk setup menu. You will find test-patterns and instructions on how to use each to set the basic brightness, contrast and color.

Do the calibration at the time of day you would normally watch TV. Calibrating on a bright weekend, but mainly watching things after 8 pm mid week may not give you the proper results.

ONE IMPORTANT POINT

We sometimes get complaints about video or audio quality - then we learn it is all based on watching crappy, pirated videos gotten from some Torrent site, or the person is still using standard def, or worse: a VCR which is 280 lines of video.

A good display looks great with high-quality HD video. But it exposes grain, noise, washed out colors, etc that we have been stuck with since 1948 if you play streaming, standard def, or a cable/sat channel where they up-converted an old TV show.

Make sure you are watching a high-quality source. Even a HD cable or sat box has a huge variable as each show is created with different quality gear. Trust the prime-time shows on the major networks (ABC, CBS, NBC) as being decent quality or a BluRay player. If these do not look good - it could be a HDTV problem. If these look good, but other things look bad, then we have to suspect the source is not great and the new HDTV now lets you see that it is poor quality.


Questions about Panasonic GT50 THX Cinema picture mode?
Q. I purchased a 50" GT50 HDTV a few days ago and I absolutely LOVE it! The picture is amazing. I was playing around with the picture modes though and i noticed one called "THX Cinema". How is this different from the regular "Cinema" mode? When i switch between them all that's obvious is that the picture looks a bit smaller but more complete (like it zooms out a tiny bit). Of course I'm completely ignorant to all this technical stuff so what do I know. Can anyone explain this to me? I the THX mode optimal for movies and such?

A. For a given manufacturer’s compliant display, THX [picture] modes are intended to provide a set of simple preset picture settings that conform to THX’s carefully chosen criteria for video image quality. Ideally the preset THX picture settings should provide the most natural or accurate video image quality short of a professional video display “calibration.” In reality, for the more demanding perfectionist it is relatively easy to surpass the image quality performance offered by the preset THX picture modes on the 2012 Panasonic plasma display panels by using the Custom picture mode along with proper display calibration software and hardware.

In addition:

THX picture modes (according to Panasonic GT50 series eHELP, page 25):

‘Precisely reproduces the original quality of the image without any revision.’

‘Recommended for playback of THX disc[s] (disc[s] with “THX” logo.) THX mode is used to mirror the picture settings used by professional filmmakers, faithfully reproducing the image quality of THX Certified movies. (THX Certified movies have the “THX” logo on a disc.)’
 

RESOURCES

THX
– THX Certified Plasmas, LCD TVs & Projectors
http://www.thx.com/consumer/home-entertainment/video/thx-certified-plasmas-lcd-tvs-projectors/
– What Makes Panasonic’s New GT50 THX Certified Displays So Special
http://www.thx.com/test-bench-blog/what-makes-panasonic%e2%80%99s-new-gt50-thx-certified-displays-so-special/

Panasonic TC-P55GT50 Review, page 2, CNET
http://reviews.cnet.com/flat-panel-tvs/panasonic-tc-p55gt50/4505-6482_7-35123235-2.html

HDTV picture settings forum: Panasonic TC-P55GT50 picture settings
http://forums.cnet.com/7723-19410_102-566046/panasonic-tc-p55gt50-picture-settings/

HighDefJunkies Forum
– Official Panasonic GT50 Series Thread
http://www.highdefjunkies.com/plasma-displays/13397-official-panasonic-gt50-series-thread.html?pp=40
– 2012 Panasonic Settings/Issues Thread
http://www.highdefjunkies.com/display-settings-calibrations-reviews/12986-2012-panasonic-settings-issues-thread.html?pp=40

Official Panasonic GT50 Series Discussion Thread - AVS Forum
http://www.avsforum.com/t/1403635/official-panasonic-gt50-series-discussion-thread-no-street-price-talk

Official 2012 Panasonic VT50 Series Discussion Thread
http://www.highdefforum.com/flat-panel-tvs/135826-official-2012-panasonic-vt50-series-discussion-thread.html
 





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