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Advanced Lenstriping

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After the 3 CRT based viewing monitor is correctly calibrated to 6500 K at the screen’s center there can be as much as a 3000 K variance from the left to right sides of the screen. This is due to the varying distances of the CRTs to the screens center. Usually the left side of the screen looks cool (blue) and has a high temperature and the right side of the screen looks warm (red) and has a lower temp.

I have measured temperatures as blue as 9000 K and as red as 4500 K. Typical lenstriping will block enough of the blue and the red guns to correct the wide variance in color temperatures. Typically I aim for a Left to right difference of less than 200-300 degrees post striping.

After the correction I have found that even though I might have an accurate color temp across the entire screen’s face I still will have a slight green hue that progressively worsens as you move from the center to the edges (green has minimal effect on color temp so the numbers don’t always show the green result). I have experimented with placing small slivers of tape over the left and right edges of the green gun and in most cases have been able to totally eliminate the green hue and actually be able to put the box the square on both the left and right screen edges.

To actually do the striping it is easiest to do it in real time. Secure the color analyzer to the screen’s surface and adjust the striping until you have it nailed on the analyzer. You will have to do this 4 times. One time each for the red and blue adjustments, then again for the left and right green adjustment. Always ensure that you secure the striping material well after the application. Below is a photo of striping on a Sony KP53HS10.

Click on thumbnail for larger image

Here are the numbers taken from the Sony KP53HS10 using the Sencore 288 Color Analyzer and Accupel High Def Signal Generator set on a 75 IRE gray field.

As always, please feel free to contact me if you have any questions about this technique.

Regards

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