Questions on brightness of old colour TVs

[Carmine]

Old TV Nut, you were right... Long read! But very, very interesting!

I really don't know how they can say what any color "looks" like, since you can only describe a color by relating it to another... In other words, imagine trying to explain "blue" to a person who has been totally blind all thier life? It would be like trying to explain a mythical color like "koorange"* to anyone else.

This is making my head hurt.

*If I ever invent anything, I'm going to name it "koorange, plahboragne, etc" because I want to ruin that rule about "nothing rhymes with oragne".

[old_tv_nut]

You are so right!

The basic science of color **reproduction** (get the basic meaning?) is color **matching**, that is how do you take a mixture of three primary colors and make it look exactly like the original color (match it or reproduce it), even though the spectra may be completely different. You have to be able to do this first, before making any of the appearance corrections mentioned below.

You are right, the way a color looks depends on the visual environment. This observation is the basis of more recent "color appearance" models that attempt to determine how the color should be reproduced in a new environment so it looks like it did in the old environment. There are a lot of things going on in the human visual system that affect these results, some of them very weird. For example, you might think that in a room lighted with orangey incandescent light bulbs, the TV reproduction should be adjusted to the same orangey white. (After all, a photograph seen in this light has all its colors biased towards orange.) But NO! when you do this to a TV, it looks way too orange - something more towards daylight-white color looks better.

NTSC, because of the phosphor changes, has for many years violated the first criterion of being able to accurately match colors over the whole range simultaneously(mostly that green phosphor change bieng compensated at the receiver instead of the transmitter, and a few other things like overly-blue white color, partial DC coupling in older sets, etc.). The phosphor errors mean that the viewer can match one or two colors to his/her preferred memory (usually fleshtones and near-by colors), while other colors have errors (strong reds too bright, cyans too dim)

PAL, and the new HDTV transmissions, at least get the color-matching capability reasonably in hand, so appearance adjustments can be made based on that. Since both the studio and the home viewer are then viewing the same reproduction, there is a chance for the artistic people to decide how they want things portrayed and get that result at home (or for the technical people to just be assured that the set-up is accurate). This standardization also makes possible the good results that are obtained with digital still cameras these days.

[andy]

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I made a post about color reproduction a while back on this one TV I have. It is this 1972 Sears 8" portable color solid state set I have. It has a delta gun tube, and no black matrix. I made sure and double checked that I had proper greyscale and background setups. I try to set all my sets for 6500K for a neutral white. I used a split field NTSC EIA color bar pattern to adjust my color saturation and hue properly. I have the brightness and contrast adjusted correctly. What clearly stands out is the green is actually green and not yellowish. It is a very distinct difference that stands right out. And the red is actually red and not orangish. Blue looks about the same, but looks like it has more contrast in it. What I have noticed is the yellow reproduction is a bit weak. But overall, it looks very different and good.

This is the only TV so far I've seen look this way. Forgive me on this as this is the oldest color set I've used in my life so far. It is a Japanese make, and the picture tube # is 250TB22.

[frenchy]

>>>I've been disappointed to see that HDTVs still let you (mis)adjust the color and tint even on digital signals. I was hoping the switch from NTSC to ATSC would finally put an end to those adjustments. There is absolutely no need for them since there is no way for the color to get shifted in transmission. I wonder if the factory defaults will even be correct, or if they will insist on sticking to a massively oversaturated picture?>>>

Probably just done for people's differing tastes, plus you can still be watching some old show or film on an HDTV that is faded, tinted, color normally tinted but washed out etc. from age or inferior color control on old tv shows. Not that I've ever needed to tweak my HDTV set just for that but I guess it's a legitimate argument. Plus tubes, plasmas etc can age differently in the 3 colors can't they? So wouldn't you need to possibly tweak them a little over time? Sure not as much as people needed it in 1959 or something where every channel was tinted slightly differently due to the accuracy back then in transmission, but I definitely want any set I own to be adjustable as per color...Frenchy

[yagosaga]

Remembering old_tv_nuts excellent contribution in this thread, I have created a plot showing the different gamuts for NTSC color television and PAL color television. When you compare the color triangles for NTSC and PAL, you can see that the color space for NTSC is larger than for PAL. Especially the difference for the green point is the farthest. The coordinates in the color triangle for NTSC (1954) are red .67, .33, green .21, .71 and blue 0.14, 0.8. The coordinates for PAL (1974) are red .64, .33, green .29, .60 and blue 0.15, 0.6.

- Eckhard

[vintagecollect]

see color CRT question other other thread


for brightness info