CurtPalme.com Home Theater Forum

[benareeno]

Has anyone tried to put some sort of tape or something on the tube face to wear level the tube? Something translucent that would mimic the light lost through the existing wear?

It would seem that this method could be more exacting than running the projector on a high contrast pattern...

the problem being, I don't know what I could put on the tube face...any ideas?

[garyfritz]

A neutral-density filter of the right darkness *might* work. But remember that as you get more and more wear, it's not just a matter of light output. The browning that happens with more severe wear also filters out some of the wavelengths and changes the primary color emitted by the tube. You can't put that back.

So maybe a ND filter could help with cases of light wear, but not bad cases.

[MikeEby]

I wonder if an HTPC app could shade an area slightly, enough to even out the wear. Problem I have with uneven wear is the edge of the wear area is darker, maybe where retrace happens?

Mike

[ecrabb]

Yeah, you could do something with an HTPC... That's what Perisoft was working on for his 808 before he understood the scope of the problem. He ended up getting a new set of tubes, if that tells you anything.

What projector, Ben.... Is this the G70? I don't see how it work without taking the tube out of the LC mount and putting it back together. Next, your "mask" for lack of a better term would be very sharp, while the edge of the wear is likely not very sharp at all. It would help that wasn't in the same focal plane as the phosphor, but that brings up the next problem... You don't get to see your results or adjust anything without putting it all back together. I really don't see how the idea would work well at all even for AC tubes, but definitely not for LC.

SC

[benareeno]

I am not looking for a 100% solution...but yes, I think an ND filter of the lightest setting could help. I could likely put it on the tube face exactly where I would want it.

I may even have some of this material at home...it looks like film, and it would likely stick right to the tube face....although LC may present a problem there, but maybe not.

[MikeEby]

[cmjohnson]

Get a full frame screenshot of each color individually projecting a full white raster. Full red, green, and blue, to be precise.

Do the screen shot at very high resolution with a very good digital camera, taken from as close to the lens center path as possible.

Load this into your PC and use it to generate a reverse mask of the wear pattern. Boost the contrast ratio until the image has a dramatic
contrast between worn and unworn areas. You want full white on the unworn areas, black on the worn areas.

Project this image and align it very carefully to match up to the existing wear pattern. Set the contrast high and run it for days, weeks, even months, in an attempt to even out the wear. Periodically check the progress and if there are any variances, make a new mask set
and repeat the process.

This is how you would even out the wear. It will work but it takes time.

The other method is to watermark all images going to the projector. The watermark is a negative of the wear pattern.


CJ

[messerfloh]

levelling the wear with tape...? Methinks, the edge of the tape will clearly be visible because you cannot fade it out...
So you might get a levelled picture with lines in it. Driving out the devil with the help of beelzebub
But, WTF, give it a try and report the result!
Nice line of thinking, though! I like such unconventional approaches!
Greetz from snooowy (at least!) Bavaria!

[perisoft]

[VideoGrabber]

Peri wrote:
> I got an inverse luminance map working in ffdshow which made wear leveling immaterial - I just used avisynth to put a luminance overlay per-channel, and it knocked the wear pattern out pretty much completely. <

That's a really slick idea!

[perisoft]