Quote:
Originally posted by Jim Banville
xilinx, I don't think you uderstand what I'm describing. My TV has always had this issue.
Thanks Old Fogey! That seems to make sense. My TV has lots of DC settings in the service menu, but none seem affect "DC restoration". |
Jim,
I've owned 4 rptvs, 2 Sonys and 2 Hitachis. All had the exact same problem you describe when displaying the black with half/white vs black with half/gray.
This is not dc restoration or any other electronic problem. It is the result of internal reflection inside the rptv cabinet. When displaying the half/white pattern the white half is very bright and some of the brightness is reflected back into the set and washes out the black half to the extent that if you adjust using the half gray pattern and switch to the half white, the moving black bars totally disappear.
Next time you play a 1:85 widescreen anamorphic dvd on your set, note that during very bright scenes the black bars above and below the image are not as black as they are during dark scenes. Since your set has squeezed raster for widescreen anamorphic dvd, these black bars are not even being scanned on the crts. The lighter black during bright scenes can not therefore be dc restoration problems but can only be the result of internal reflection. If your bright scene is primarily a color other than white, say a bright blue or red, you'll note that not only are the unscanned black bars lighter but they are also slightly tinted blue or red.
I have noted that each new set I get has progressively less of this internal reflection effect, and also that it can be reduced just by cleaning the crt lenses. Some ISF calibrators and adventurous rptv owners have lined the set's interiors with duvetyne non-reflective fabric and made hoods for the crt lenses to further reduce this effect.
In any case it's pretty much a characteristic of rear-projection tv, and is not an electronic malfunction but an optical anomaly.
I've always used the black with half gray pattern exclusively for brightness adjustment, after turning contrast down to about 30-50%. I store 30% contrast and the appropriate brightness under Pro, and progressively higher contrast settings under Movie and Standard and switch between the various picture modes according to the ambient light variation in the room for daytime vs nighttime viewing.
Usint only the half gray pattern gives me the best overall compromise.