Saturday, May 30, 2009

Color Calibration Confusion - Temperature Rising

Some of the readers from Highdefjunkies Forum had questions about my recommendation for temperature settings for calibration. 

I state in the WOWVision! text:

"Temperature - Use the "Low" or "Cool" or 6500K setting - or whichever setting is opposite of warm." Yes, opposite.

I will attempt to explain the relationship between 65K/6500 Kelvin and the "Cool" temperature setting on the television. Perhaps I could bring some "light" to the subject  in what I will call:

Why is the temperature of a WARM white light 2000 degrees COOLER than a COOL white light?

I am attaching a couple of light temperature charts that should shed some lig...that should be very helpful in this exploration. 

Here is a part of the problem. We have two conflicting arenas for description, and even two seemingly "contradictory" sets of terms to describe light. We describe light by its color, by it's temperature, and by its "feel". 

To illustrate this, let's consider fluorescent light bulbs. We have fluorescents that are termed "Warm White" and "Cool white" and also, "Daylight". 

"Warm white" fluorescents are found in rooms and places where you desire a "warm emotional atmosphere". They are generally dimmer than the others and they emit a more red spectrum of light. This light is considered to "feel" warm. Red as a color is described intuitively, as warm. The red coals of your fire are around 2100K. They glow with a red light, and the coals are cozy and warm. We attribute the "feeling" of warmth, to the color red. When the quality of this light is quantified on the Kelvin scale, it has a Kelvin temperature of around 2100k. (Kelvin temperature scale refers to the light emission of a black body heated to a specific degree, like a charcoal briquette that glows red.)

The cool white lamps are what is most commonly found in fluorescent fixtures today. Without a trained eye or a side-by-side comparison, these lamps are perceived as white, thus the white of "Cool white". Cool white's color emissions, however, are in the yellow visible spectrum and the lights are indeed yellow. COOL white registers on the Kelvin scale around 4100k; that's 2000 degrees HOTTER, than WARM white. Cool white emotionally "feels" cooler than the red light. Want a hot room? Paint it red. Cool room? Paint it blue. 

In the last few years it has come to has been found that the yellow "Cool white" fluorescents cause eyestrain, computer screen glare, and mood swings, ushering in the days of the Daylight fluorescents.

What is so special about the Daylight bulbs? "Special" is called "Full Spectrum" in lighting or light. These lights emit THE spectrum where WHITE light resides. These lamps give you vibrant colors in a store, and make everything look cleaner. They are also good for your health (complete like sunlight), used to treat bilirubin deficiencies and depression. These are one type of lamp used in color matching and they are also great for use as grow lamps! (Settle down out there!) And guess what? They come in at 6500 on the Kelvin scale. These are truly the white lights because for something to emit the "color" white in light, all of the colors of the spectrum have to be there, because white light is comprised of all of the colors. (Don't confuse this color mixing in light with painting or pigment! In pigments, the opposite is true. Gee that helps, too.) 

The reason why Daylight bulbs produce the most vivid color, is that all of the colors of the palette are available in white light. The reason why 6500k is desirable in a television is exactly the same. 

Now reference the color charts and take a look at how the mix of terms and temperatures clash. 

Now add the television manufacturer's who can't or won't standardize a remote control, user menu, or even the same term for the 

"aspect ratio/format/ZOOM/Picture" button. Did I miss any? 

Anyway, some manufacturers use LOW/MEDIUM/WARM, some use COOL/NORMAL/WARM, and there are still others. (We'll find out soon enough.) 

To refer once again to the lighting situation, why does the warm white fluorescent lamp produce a redder room, and why does a cool white lamp produce a yellower room? Because they lack the parts of the spectrum to produce white, in other words, they don't have all of the colors available to produce white. 

What if you use the "warm" temperature setting like everyone else recommends? 

I believe that within the calibration world there is a bit of unintentional confusion on this one. That would explain why EVERY television is "hot" on the red. 

One thing I am certain of is this: It doesn't take a week to see a great picture, or WOWVision! would have been named, "Call-you-in-a-week-Vision!"

Saturday, May 23, 2009

Why did Dish Network change their signal meter?

Why Did Dish Network Change Their Signal Meter?


Recently, Dish Network sent out an announcement that there has been improvements made to their signal meter. The "improvement" did several things - none of which are an improvement from a troubleshooting or an installation standpoint. Let us examine these changes.


One change was to even all the signals across all receivers.


Prior to the signal meter "improvement", each of the receivers (by model number) had different readings. Receivers with the same model number all showed similar signal. The signal meter showed the highest signal readings on the simplest receivers like the 301. Each successive receiver showed a lower reading with the HD/Dual/DVR receivers showing the lowest of all.


The signal meter readings were different for good reason. Two good reasons, actually. The readings reflected the added intrinsic noise of the receivers and they showed the greater signal demands of HDTV.

Dish meters measure signal quality/fidelity/integrity, not signal strength. The meter reflected the difference in the signal integrity between the receivers.


Given: The same signal STRENGTH produces less signal integrity as you add noise.


Each of the higher numbered receivers showed this decrease in integrity as additional components added noise and reduced the integrity of the signal (dual receiver-added tuner etc, DVR capability).





Given: The same signal STRENGTH produces less signal integrity for an HD signal than it does for SD.


The astounding jump to the lowest signals ever, those of the HD models, reflect the need for additional signal. (Warning: Cliff!)

The effects of the leveling signals across models:


Removes the ability to compare other readings in the home.

Removes the ability to switch places with an existing receiver to check the signal integrity of the line.

Removes the question of “Why there is plenty of signal on my SD receivers but not for my HD?”


A second change was to change (reduce) the scale of the signal meter.


Reduction in the scale of a measurement device causes a reduction in precision. (Sad.)


Changing the scale also did away with the one benchmark that there was in digital scale meters. That benchmark is/was 70. Here again, while few remember that there WAS a standard, those who would apply it to the average HD signal readings found across the country would see that HD signal is pretty much ready to fall off the digital cliff! 


Effects of reduction of scale:

Reduces the precision of measurement.

Negatively impacts troubleshooting and installation.

Confuses installers and customers.


Effects of changing the scale:

Lost benchmark

Confuses installers and customers.


Now, of course, there is much guesswork about what is good signal strength. (And the benchmark of 70 that is still used in digital technology, is just not used by Dish.)


Lastly, in the signal meter "improvement", Dish also saw fit to increase the latency time for channel changes.


At present, all receivers read the same meter readings (HD’s lower readings) and all of them change channels far slower than ever. (They increased buffer size to try to accommodate their cliff-dwelling signal, but I’ll address that later.)

Why would changing the amount of time it takes to change channels matter?


As a troubleshooter, the first evidence of low signal readings was slow channel changes. Now they all change at the same slow rate.


Effects of latency time:

There goes another troubleshooting method.


So why did Dish Network change the signal meter?


If you are still wondering why, perhaps you should tune in for part 2.

Something smells fishy, very fishy.


Monday, May 18, 2009

Why Does My SDTV Look So bad?

Why Does My SDTV look so bad?
Guess what? It isn’t “compression” or “dilution” as nearly everyone will tell you!
One thing that needs to be understood is that color calibration is the “missing-link” for those who wonder why "Joe's" TV looks so much better than theirs, and/or why their SDTV (standard definition viewing) looks so poor on their new flat panel. 
Spyder Pro Calibrations - Caution
First, do not spend even $99.00 using Geek Squad or any others who use the Spyder Pro Colorimeter. The Spyder Pro always leaves the picture too hot (red) which is the initial condition of the TV's anyway. Worse than that, you aren't at a place where you can just drop the color by a couple more clicks to get it right. The picture quality IS better but close doesn’t count in calibration. Invariably, I had to re-calibrate by eye, anyway. Using the Spyder Pro was a great learning experience, though. After awhile I found that a “standard formula” for a starting point, and then calibrating by eye, is far better than using Spyder Pro.
 ISF Certified Calibrationist - Caution
I suggest avoiding the professionals unless you have a projector or an actual problem with your TV. If you do use an ISF certified calibrator, get references and check his work FIRST. Then you will know if what he does is what you want.
 See The Colors as the Director Intended
Adjustment of the colors to "see what the director intended" just isn't a reason to drop a chunk of change. What do I care if the actors tie is fire engine red or carnation red? It isn’t nearly as much about “true color” as it is about details. What the calibrationist don’t seem to know is that proper color calibration greatly affects the amount of detail that can be rendered. 
 HDTV is all about details.
When your colors are correctly set, they produce life-like renditions of skin tone, nature, and life. That's pretty cool, but for the condition of "WOW" to exist - for HDTV to exist at all - we need details.
 Many of you can look at your TVs right now and scroll through the channels, and as you do, many of you will find that:
skin tones look unnatural,
            everyone looks sunburn,
men's lips appear to have lipstick, and
the scrolling news headline tickers are not very crisp.
And, many of you think your HD is good, but your SD is unwatchable. 
So, try it for yourself. Scroll through your channels. If you see the things listed above, you need a calibration. (If you didn’t see those before, I’m sorry…) If you don’t see those things, don’t waste your time finishing this blog – you don’t need calibration.
So the skin color is off. That doesn't sound like much of a problem, does it? But when the color is incorrect, you don’t just have some slightly annoying skin color, you have a TV that can’t reproduce the subtle shades and nuances that add reality and texture.
 Color Vs. Texture
Colors create an objects color, but shades and tints produce it’s TEXTURE. Texture changes your viewing from a flat, pretty picture, into realistic, WOW! HIGH DEFINITION. It is one thing to see the putting green and a whole other thing to see the blades of grass of which it is made.
How Color Calibration Will Affect SDTV Quality 
After a proper color calibration, your SDTV viewing will look very good with some channels coming deceptively close to HDTV quality. The amazing technology in your new TV is so good at presenting the information contained in the signal that it will also reveal how far from “WOW!” your HDTV actually is. The good news is that you can expect great SDTV on a properly installed and calibrated system with good signal strength. 
Color Calibration Reduces Motion Blur and Sharpens Tickers
Yep, it does.
 How important is Color Calibration?
Color calibration is paramount and integral to the amount of detail that your set can provide. Important? YES. Costly? I hope not. Hard? Takes practice. Fast? With time. 
 God bless you, and thank you for reading!
Highdef Jeff