DLP Rainbows

[Guest]

Will this effect increase as the projection bulb ages?

[BJ_M]

no -- it is from the color wheel , not the bulb

[Guest]

Well the weird thing was that I didnt notice it for the first several months of owning the tv. It seemed to come on all at once so I was thinking it might have to do with bulb age

[turk690]

Some things will make the rainbow effect more noticeable, like blinking your eyes rapidly (the speed with which you blink will make you see differing widths of RGB swatches). Another is watching an NTSC program (59.95Hz field rate) in a room which lit from a 50Hz source (or conversely a PAL program (50Hz field rate) in a room lit with 60Hz source lights): on first generation DLP projectors the 10Hz beat accentuates these rainbows galore. O could be that the color wheel is not syncing properly (unlikely but possible). Recent consumer models avoid this rainbow effect by having faster spinning color wheels and professional digital theater projectors do away with the color wheel altogether by having 3 DMDs, one each for R, G, B. As an aside, before RCA invented color subcarriers and the color picture tube in 1953 for a complete all-electronic color TV system, the first attempts at color TV were done with monochrome tubes and...color wheels. They're back, indeed.

[BJ_M]

when you're tired or if been drinking -- often more noticable also ..

higher end projectors also use 6 segment wheels now ..

[flaninacupboard]

the effect put me off buying DLP altogether! i was after a display last year, DLP had the pretty colours (reminded of my 1970's front projection tv from Rank) LCD projectors were grey, plasma was grey (and slightly smeared) and didn't seem to handle resizing very well. in the end i just got a CRT. on my shopping list now is a progressive CRT projector. something like a Barco Cine 7LT. mmmm, 75mhz and a contrast ratio of 15,000:1 Sweet.

[BJ_M]

the better dlp's do not have the rainbow effect - nor do any of the 3 chip units of course ..

the Barco Cine 7LT is a nice unit if you dont mind only 750lm effective brightness, so it would be good on a 6-7 foot screen .. or that the fact that units require constant adjustment and are known to be very problem prone .. they also have a lot of motion artifact from thier built in line tripler - barco never could get a good motion video on any fo thier projectors of any type