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I had my old CRT TV calibrated yesterday. Wow!

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    I had my old CRT TV calibrated yesterday. Wow!

    Just thought I would share the data behind the excellent results Lyris had with my old TV yesterday. The difference is far greater than I expected. Seeing the difference in the image and knowing that the process will also help prolong the life of this TV it seems well worth the money.
    I have a couple of before shots of Donpachi which I will retake with all the new settings applied. I'll get a few other pictures when I get a chance.

    PRE-Calibration



    Greyscale tracking before calibration was consistenly too blue-green. The level of blue is so high, and red so low, that they are both off the RGB Level Tracking chart. That resulted in everything on screen having a blueish wash over it. When the CRT was new, it was probably blue tinted to start with, but I imagine it's got worse over time. In fact, the colour temperature overall measured at something like 10,000K - which was probably not good for the tube. NTSC, PAL and HDTV video standards all use an overall colour temperature of about 6500K, equivalent to neutral sunlight.

    Delta errors (dEs): for reference, an error of 3 or lower is generally at the level which won't result in a visible tint being recognized by the eye. Pre calibration, the Loewe CRT had errors of about 40-50.

    Dynamic range was fine - you weren't losing much shadow detail to start with, and there were no blooming whites. I think you mentioned that you calibrated both of those by eye using Digital Video Essentials before, which would explain that. Those are two of the only controls that can be set properly with an eye and test pattern (Greyscale tracking obviously needs the meter).



    As for colour, the hue and saturation of the outer colour points was not too bad. The colours of red and green are quite close to spec. Cyan and Magenta have huge errors, as the blue tint imposed on the picture by the inaccurate greyscale was distorting these quite visibly. Luminance levels were typically too low (coloured blocks = targets, black blocks = your screen) resulting in mildly washed out colour.

    POST-Calibration



    Visible greyscale tracking errors are now non-existent. All 10 measured points display with nearly perfect neutrality. Delta errors are all below 3 so will be invisible to the eye. Achieving flat greyscale tracking on a CRT is unusual, especially if it's had 8000 hours on it. Since it's from 2002, the TV "only" has 2-point greyscale control, that is, control over the low end (Dark areas) and high end (highlights). Some trade-offs were necessary; in the end I went for a couple of % too little red in the shadows to avoid huge errors elsewhere. Balancing the tiny remaining errors out basically results in them being invisible.

    Gamma is tracking at a fairly flat 2.2. This is very good luminance distribution for everyday environments (rather than blacked-out, light treated home cinema rooms).



    Colour gamut errors are all but gone now. Again, all of your delta errors are under the visible point of 3 (compared to cyan's 18 before). This is a damn good result considering that the CRT had no colour controls beyond simple Colour (which was largely a colour luminance control; not a saturation one) and Tint (which didn't do anything with RGB signals anyway). Most of the improvements here come from setting the basic Colour control to balance out remaining errors, and also greyscale calibration which removes the blue-green mist which was being added to everything before.

    It conforms pretty closely to the EBU colour gamut. Although we were calibrating mainly for NTSC, I didn't attempt to hit the American standard def SMPTE-C gamut because it wasn't used in Japan, where almost all of your games were developed in the first place (in SD, Japan obviously used 60hz NTSC but with the EBU gamut). Also, since the gamut on CRT displays is defined by the physical phosphor material in the screen, it likely wouldn't have been possible anyway, although the difference is small. The world is now on one colour gamut standard for HD.

    Geometry is also improved now too. It can never be perfect on a 32" consumer CRT, but you have more of a visible image now with less overscan, and also less of a pin-cushion effect. The biggest improvement is to greyscale of course, which leaves you with neutrally coloured images which are better than some uncalibrated pro CRT monitors. The apparent depth and lack of murky blue tint speaks for itself, as we saw! Now it's calibrated it'll also last longer.

    We also investigated the different picture settings and found out which one was giving Interlaced and Progressive display output (and how the control differed with 50/60hz input). Leave it off for retro scanlines

    #2
    I have no idea how to interpret these graphs (never have!), but I'm sure it looks awesome.

    I'm sure this would yield amazing results on something like Shozuki's BVM. Probably not worth the cost for something as rubbish as my 9" PVM. lol
    Last edited by speedlolita; 10-11-2012, 10:55.

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      #3
      I should have taken more before shots to let people see the difference. Your PVM would no doubt show some improvement. And helping to increase the longevity of your CRT has to be worth some investment.

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        #4
        I don't think it's big enough to bother doing it honestly. I'll be on the lookout for a 14" soon enough I think.

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          #5
          Glad it went well, Craig - it was a hell of an improvement!

          Regarding before and after pictures - those can sometimes be a bit misleading, depending on the camera. One of the main things cameras do in their auto mode is... correct the white balance (which is basically what's done to the TV during greyscale calibration). It depends whether or not the camera uses an object in the room, or an object on the TV screen, as a reference. Then, you also have the monitor the picture is being viewed on to consider.

          I have no idea how to interpret these graphs (never have!), but I'm sure it looks awesome.
          Basically, straight lines good, wavy lines bad.

          The main thing is the RGB tracking chart. I've reuploaded the charts below, since Imageshack seems to be messing up. Look at the 100 percent position on the Y axis. The X axis shows the different brightness levels, from full black at the left to full white at the right. The Y axis shows the prominence of each colour making up grey (we think of grey as colourless, but on an uncalibrated TV, greys are tinted). A calibrated TV will have an equal amount of red, green and blue making up the colour of grey at each brightness level, meaning that the red, green and blue lines on the chart will come very near to crossing together at 100%. If they do that, it means the picture is free of tints. Not only will it be consistent across brightnless levels, but it also has to be the correct colour of grey - the same colour of grey used during the production of films/TV shows, which is 6500K (same as neutral sunlight - not an accident!)

          An uncalibrated TV will typically have sky high levels of blue contaminating the greyscale (that was the case here), and often it will have a different coloured tint in the shadows and another one in the highlights. That results in an unnatural picture, because all of the colours on screen have to hide behind this heavy tint. And also because, the human eye doesn't have nonlinear greyscale tracking - which is why you often hear people who have had displays calibrated say that they look much more natural.

          That's just greyscale though. There's also the 3 colour attributes as well as defeating the image "enhancement" features!
          Last edited by Lyris; 10-11-2012, 15:42.

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            #6
            Yes I remember the old rule with colour CRT's was 'get it right in black and white'. So long as the grid volts are what they should be (as in the service manual), and the tube isn't too low on emissions (tested with a CRT reuvenator), it's much easier to set up the the colour balance accurately.

            CRT's can be temperamental little ****s, and most were never really set up accurately at the factory (apart from some of the more expensive models) - the priority being decent enough picture and sound via an aerial feed. Even then most of the original variables will drift over time through general wear and tear.

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              #7
              Reminds me of this video. :drool:

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                #8
                I cant see the sexy pics, CMcK

                Also, what model is your CRT and roughly how old? I just know my old Tosh would provide some glorious results post cali but I cant afford it and my mum would kill me as shes desperate to throw the behemoth out. Its a 70kg BEAST!
                Last edited by bash; 10-11-2012, 15:34.

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                  #9
                  I'll get some pictures up on Monday.
                  The TV in question is a Loewe Aconda 32" 9281ZW. I bought it in 2002 IIRC. Halo was out on the Xbox and was the first game I played on the new TV so I'm pretty sure it was around then.
                  As noted earlier the TV has over 8000 hours according to the log on the set.
                  It was an expensive set at the time so I'm glad to see that even now that it was money well spent.

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                    #10
                    sh1t, I heard they produced some nice results out of the box anyway but good idea to get it calibrated. 32" was a decent size but they went beyond 36" and had geometry problems if memory serves correct . . . .

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                      #11
                      Yeah there was a 40" version of that TV but the tube wasn't quite as flat as the smaller models.

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                        #12
                        MEhhhhhh... You can't beat simply twiddling with the knobs for your own personal preference. ;p

                        Calibration Schalibration

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                          #13
                          Before and after shots. Not exactly great quality but does show the difference in the colour.

                          Before:


                          After:


                          Before:


                          After:


                          I tried to take some action shots but they turned out a bit fuzzy.

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                            #14
                            Probably not the best idea to use a Tate game in Yoko mode to demonstrate your CRT.

                            Especially when the games are formatted so poorly that they make your geometry look off.

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                              #15
                              And that game scales the playfield as well. I just grabbed a few pictures before Lyris arrived and that was the last game I had played. I'll rake out a tripod and get some better shots when I'm off.

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