Does anyone make a visual confirmation tool to verify calibration? - AVS Forum
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post #1 of 9 Old 06-15-2013, 04:49 AM - Thread Starter
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I've been thinking about what I see as a weakness in the calibration system of not having a reference to compare your display to. This would help avoid the charts look great but the actual display looks too (fill in the blank).

For instance, calibrators will say that they view actual content to confirm their calibrations but what are they comparing it to? From what I gather, it's what they think it's suppose to look like. Relying on memory is a pretty bad idea too not to mention that you can look at an off color image long enough and after a while, it starts to look O.K. You also have issues with color vision.

In any event, what I'm looking for is a system where we would have reference photographs that are viewed under D65 lighting (or something very close to it) and a Bluray properly mastered showing the exact same images. In this tool, there would also be variation of the correct image surround the correct image to give you a clue as to how your image is off. We have something like this in print photography to help assure color accuracy. We'd want to extend this to include the variations in gamma, If you're targeting 2.2 and you've are actually getting 1.8, wouldn't you like to know it?

Does anyone know of an existing system/tool to do this?

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post #2 of 9 Old 06-15-2013, 05:10 AM
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And what are you using to compare this magical inexpensive optical comparator with your now measured and calibrated display?.. wait let me guess, your EYES! eek.gifbiggrin.gif
Yes I feel your pain if all you have ever worked on is one or 2 TVs how do you know if it is correct.. but fortunately for all of use we have meters and software that can get things very close, way better than just a few years ago..
You stil lhave to look at the output of the display and you will eventually know what is correct and what is not.. What you ask about has been asked about many time in the same and different ways.. it just doesn't work like that at this time!
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post #3 of 9 Old 06-15-2013, 06:24 AM - Thread Starter
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Quote:
Originally Posted by airscapes View Post

...snip...

You stil lhave to look at the output of the display and you will eventually know what is correct and what is not..

That's my point. You can't just eyeball an image without a reference and know these things. The eye is very good at seeing differences in color provided you're not color blind to any degree.

If you disagree, then fine. I have a 25 year background in professional photography including a studio operation containing a color lab. I'm pretty convinced that you have to have a reference to make comparisons to in order to have confidence in your picture accuracy.

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post #4 of 9 Old 06-15-2013, 12:21 PM
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There used to be an optical comparator for use in setting/verifying grayscale. Essentially it was a D65 light source and light and dark gray cards in a housing like that of a VHS tape. It was expensive and only good for grayscale.

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post #5 of 9 Old 06-15-2013, 12:58 PM - Thread Starter
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Thanks Royce.

I'm interested in something broader than grayscale.

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post #6 of 9 Old 06-15-2013, 07:44 PM
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The problem with an eyeball reference is that it would only work if you knew in advance exactly what the reference was supposed to look like. How could you ever know that?

I have always thought that having temporary access to a reference instrument would be a useful tool for the non-professional, but I haven't seen much interest in this.

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post #7 of 9 Old 06-15-2013, 07:49 PM
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Yes, you CAN view content you know well to confirm that you have a good calibration. I have been using Casino Royale (Daniel Craig version, of course) since that disc was released. There are a SLEW of places in that disc that are torture tests for calibration results. And once you have viewed the movie numerous times on well-calibrated video displays of all kinds, when you get a poor result, you can see it quite easily. But ONLY when you have viewed the content so many times on properly calibrated displays so that the scenes you select are committed to memory... just like a STOP sign or Coke red... things you have seen so many times it is OBVIOUS you are not seeing the right shade of red.

For example, in Bond's rental car... the license plate and the paint on the car are close to the same color but not exactly the same color. There are numerous scenes where you see sea and sky in the same shot and there are a fair number of variations in the color of the sea in those scenes. The shot from Bond's hotel room in Venice looks more 3 dimensional when gamma is correct than when gamma is too low (numerically) or too high. You get to know those scenes and others over time.

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post #8 of 9 Old 06-15-2013, 08:49 PM - Thread Starter
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Quote:
Originally Posted by TomHuffman View Post

The problem with an eyeball reference is that it would only work if you knew in advance exactly what the reference was supposed to look like. How could you ever know that?

I have always thought that having temporary access to a reference instrument would be a useful tool for the non-professional, but I haven't seen much interest in this.

You'd have the exact same image in a photographic print that you're are viewing on the display. For example, the dinner scene from the video essential DVD. Do you really know if the woman's complexion is peachy, bronze or yellowish. Does anyone really know? If you have that exact image in a correctly printed photograph properly illuminated to compare to the display, that would help the user determine if his calibration is off. Actually, you'd have several pairs that you'd be comparing such as different APL levels, gammas, and other variables.

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post #9 of 9 Old 06-17-2013, 04:43 AM
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According to displaymate site the retina display on ipad3/iphone4 is so good out of box that they don't need calibration and isf released a grayscale comparator so in theory it should be able to display a reference photo/video mastered to D65 rec709 but idk how you would handle gamma?

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