Halolight rides again! (semi OT)

[Phil Nelson]

A while back, in a discussion of the Sylvania Halolight, I asked rhetorically why, if it's such a good idea, no other manufacturers copied that feature.

Guess what -- Philips just did. We have one of their Ambilight sets with the backlighting. I wonder whether the halo light is actually an improvement.

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

[Tom_Ryan]

Say, the article mentions that the HD makes use of reflective surface to give the effect of an endless screen so I guess that would only qualify as passive halo lighting. I was really expecting Philips did something like Sylvania and mounted a light behind a translucent bezel for an active halo effect...not the case.

[old_tv_nut]

Visually, halolight only extends the bright picture area to a new abrupt edge, so I would think the Philips thing with a gradual reduction in brightness away from the picture is better. Also, you have to remember that halolight was introduced when only B&W image orthicon cameras were in use, which had only the roughest gamma correction by running the exposure beyond the "knee". This means that the brightness contrasts between objects in the image were not very true to life. The effect of halolight to some extent was to make the image appear more contrasty to the eye, which may have been good on some programs. Applying that to a modern HD system, which should have proper tonal rendition to start with, is somewhat suspect. Anyway, a properly produced program is judged for tone and color with a master monitor that is viewed against a neutral, low-brightness background (don't recall the exact percent of image highlight brightness, but let's say 10%). IF the Philips is set to produce a constant low level neutral background, then it will show you what the program source was supposedly set up to look like. The changing-color idea is more or less a gimmick effect; nevertheless, you may subjectively prefer it even though it's not what the program producer was aiming for.

[Tom_Ryan]

Yes, the extension of the picture at edge the using an active halo ring was meant to extend the picture gradually to infinity. It's not abrupt because when seated at the correct distance from the TV screen the halo edges are actually in the peripheral view of the eye - no color there just b&w light detection - shapes with no clear definition. Psychologically, the mind fills in the rest. I think your story about gamma correction is mute since most TV manufactures in the 1950's thought Sylvania's halo light was a gimmick. To a great extend I agree with you that it's still suspect even today. Heck, the same concept is being marketed today by Philips as "ambilight" HD television. Kinda wierd that the ad copy didn't make that clear. Here's a live link from Philips to explain what the halo "ambilight" process.

http://www.flattv.philips.com/shome.htm

Marketing madness for sure but it's kinda cool