Some people go by that, but it is a little bit more complicated that that.
Anybody can make up their own definition, but to use the 4K UHD logos from the CTA standards group there is a display resolution requirement:
Display Resolution—Has at least 8 million active pixels, with at least 3840 horizontally and at least 2160 vertically. Physical pixels shall be individually addressable such that the horizontal and vertical resolution above can be demonstrated over the full range of colors provided by the display.
Originally they just had the 1st sentence and then added the 2nd one later. I have some suspicions that at least some of these XPR DLPs can't actually do colors above about 50% luminance (or something else less than 100%) for the bright lines while demonstrating the horizontal and vertical resolution, but I couldn't get a BenQ XPR projector to even work reasonably for a single pixel vertical green line pattern in 4K space, so I couldn't check how they actually prove the horizontal resolution they claim.
Since companies are allowed to self certify TI could claim that they meet all the requirements by just going by the original version of the CTA requirements (which don't include the full color range requirement), or they could interpret the 2nd sentence in a way that allows them to qualify. It is possible that they can really do the full range of colors (where generally luminance is part of a color), but I will doubt it until I seem some evidence about what sub-frames they put up in order to show a single pixel line pattern.
I asked somebody from the CTA group about this second sentence and was told that the group isn't currently active and they would have to investigate to see if the group agrees that TI passes (which it doesn't sound like the group will do). If the group investigated and decided that TI cannot do the full range of colors while demonstrating resolution they could always change the requirements again to allow TI to pass.
The best I've seen for an XPR projector doing a single pixel line pattern in 4K was a picture sage11x ran it on his 1080p plus 4 way XPR W1700, which is IMO a pretty poor example of showing single pixel green and black lines that are supposed to be the same width:
Originally Posted by stanger89
It's a question of what do you count, the composite image that is perceived, or each individual component as it is displayed instantaneously?
If you say each individual component, then DLP can display 8.3 million pixels (4.15Mpix * 2 or 2.07Mpix*4), but it can only display 768 (or less, if you say it's not actually 8-bit) colors since it shows each color sequentially, which means it maxes out at 256*3 colors.
Not sure how you are counting a component here, but a single chip DLP can only show 2 colors at any instant (the current colorwheel color and black). Even to get 256 steps you have to integrate over time.
A 3 chip DLP could do 8 colors at any instant in time.