Blue blooming - has anyone ever done the Scheimpfluge on their RPTV?

Discussion in 'Displays' started by Dan Kolacz, Oct 21, 2003.

  1. Dan Kolacz

    Dan Kolacz Stunt Coordinator

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    Hi,

    My Sony KP-61HS30 RPTV's blue CRT is blooming everywhere on the left hand side. It affects a little over 1/3 of the screen from the left to almost the middle.

    It is most noticeable when there is a bright area next to a dark area. The dark area is overflowing with brilliant blue light from the bright parts. If the right scene comes up, the blue blooming may extend for over 1/2 an inch into the dark area, so it is really visible!

    I have had a great ISF tech come out to my house, and he adjust the set nicely, and when he focused the blue CRT to be the tightest possible (can see the scanlines), this blooming problem exhibits itself.

    I emailed him, and he suggested that I play with the focus to try and resolve. If I change the mechanical focus, I can lessen the blue ghosting/blooming, but then my blue CRT is really defocused.

    He actually came out to my house this weekend for a return trip to take a look. He touched up the greyscale and redid the focus for all the CRTs, and the blooming problem is still very apparant as described above.

    I heard that this Scheimpfluge adjustment may resolve this issue. Has anyone had this problem and resolve it with this? Is it easy to do? Any tips?

    Thanks
     
  2. Dan Kolacz

    Dan Kolacz Stunt Coordinator

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    bumping - anyone????
     
  3. Gregg Loewen

    Gregg Loewen Video Standards Instructor, THX Ltd.
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    Dan,

    Shimming a lense could help but is quite risky to do. The same was done with my Toshiba. HOWEVER, huge problems developed, first the blue could not be moved over enough to compensate for the now shifted image, so the blue then became the template and green and red were converged onto the blue. This made the convergence generally unstable and I had to touch up convergence at least monthly.

    I strongly suggest you leave the set as is, as I thought it looked quite good. When viewing BandW material you could not see any problems on the upper left portion of the screen. I think that if you attempt the lense repositioning you will be opening a huge can of worms.

    regards

    Gregg
     
  4. Dan Kolacz

    Dan Kolacz Stunt Coordinator

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    First off: If anyone is curious in seeing pictures of what we are talking about, reply to this thread with your email, and I will send you some.

    Thanks


    Hi Gregg,

    We didn't watch enough material for it to surface. The only time it is visible is when there is a brightish white area next to a dark area (which, unfortuantely is fairly often).

    Any scenes that meet this criteria it, the bright blue is glaringly obvious.

    The very left edge of the screen (like the last 2-3 inches) the bright blue blooming is so pronounced that there is over an inch of bright blue. When the white/dark borders are running vertical, the entire left hand side is blooming about an inch into the dark area. As we move more towards the center, it is about 1/2 an inch.

    Remember those picture I sent you from that scene in Kubrick's 2001? It still looks like that in that same scene.
     
  5. Dan Kolacz

    Dan Kolacz Stunt Coordinator

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    Actually, if you would like to see pictures, please email me: [email protected] and I will send them.


    Also, I just wanted to mention that I am not criticizing Greggs work at all. He did a hell of a job on my set. The picture looks fantastic otherwise.

    I would not mind this problem if it was a little less noticeable and less frequent, but unfortunately it is TOO noticeable and TOO frequent.... [​IMG]
     
  6. Gregg Loewen

    Gregg Loewen Video Standards Instructor, THX Ltd.
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    hi Dan

    I dont really think there is a "easy" fix for this.

    How old is the set? Warranty? Perhaps a replacement?

    If really bother some then try the lense shimming.

    Perhaps moving your couch back another foot or so would be of some benefit??

    I would be more than happy to talk you through the shimming (Scheimpfluge).

    Regards

    Gregg
     
  7. Michael TLV

    Michael TLV THX Video Instructor/Calibrator

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    Greetings

    Every set has some imperfection and this seems to be yours. On occasion ... slamming the blue mechanical focus left and right to the edges of the bolt's movement might jostle the lens and change its overall focus characteristic.

    Not a fix ... just sometimes it might work ... or not ...

    Regards
     

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