question about early color tv
 

Hi,
I have often heard people describe early color televisions as having "saccharin colors"
Why was this? Were the colors much more saturated and beautiful?

Since we're on the subject of color,why was it that the old films like "Artists & Models" with Dean Martin & Jerry Lewis and 1963's "The Nutty Professor" have dazzling beautiful colors that really explode on screen and then by the late 60's the films all looked dingy,grainy and washed out?

I would have posted this second question in a film area but couldn't find it.

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The early CRTs had sulfide phosphor, which caused the greens and reds to be much deeper. After the mid-50s, they went to rare earth phosphors, which made less-deep greens, and orangish reds.

Charles

Thanks Andy & Charles!

Why did they switch to the rare earth phosphors if they didn't produce as vibrant colors?
I have noticed too that early color sets used a dot type mask,while eventually most modern CRT tv's adopted line style masks.
I think Sony had that type first,but I'm not sure as I am mainly interested in 50's early 60's sets.

To address customer complaints of lack of brightness, which is apparently worse than correct color reproduction in the eyes of the consumer.

Yah, it's hard to describe the difference, but on my early color TVs the reds definitely look more cherry-like when played side by side with a modern set. I guess "deeper" is as good an everyday term as any.

Not sure about the correct technical term . . . the reds generally have higher saturation?

Phil Nelson

I think it was also to make the tube last longer.

I recall reading they had to drive the red gun twice as hard as the blue and green because the red rare earth phosphor wasn't as efficient.

Rare earth after the mid 50's? I thought it came out about the time of the 25" crt.

Both films, Artists And Models, and The Nutty Professor, were shot in Technicolor. Technicolor stopped doing this process in the early 1970's.

You should see an original Technicolor 35mm print in a theatre. The color will knock your socks off!!

Sorry, I meant Sulfide, or whatever the red was made out of in the early tubes.

I would love to!

Unfortunately there aren't many old movie theatres left still in operation that run those great old films.

Many years back I used to work at a movie theatre that was 50+ years old and we ran the old movies and cartoons and it was great!...but it didn't bring in any money so they closed.

That place even had the original carbon arc projector and voice of the theatre speaker behind the screen!

So why did Technicolor stop making that film when it was so incredible?

There's some confusion in the discussion of phosphors above.
Original NTSC tubes (15GP22) used non-rare earth red (very inefficient), P1 (Willemite, oscilloscope tube) green (which was less yellowish than modern green), and a blue that was not so deep violet-blue as today's tubes.

21AXP22 still did not have rare earth red. At some point the blue moved more towards modern blue. The green was still P1.

Later, all-sulfide tubes were introduced, with better efficiency of the red and green, but the red was slightly more orange and the green was definitely more yellowish. The blue also had moved to the modern blue. The yellower green eventually caused a change to be made to the color demodulators to get good fleshtone hues, by increasing R-Y gain - but this tended to overdrive the reds, making them overly bright as well as slightly more orange than NTSC. This effect tended to mask subtle differences in red objects, especially if the color was turned up.

The eventual use of rare-earth red made the tubes even brighter and more efficient, but did nothing to change the flesh-tone correction and overly bright reds. This situation continued forever in NTSC. Meanwhile, in Europe, PAL decided to matrix their cameras for the modern green phosphor instead of increasing R-Y gain in the receivers. This results in proper reproduction of both pale (skin) and saturated reds, and is essentially the same tack taken in HDTV (and digital still cameras and computer monitors, where it is called sRGB) today.

In summary, a lot of the complaints about the orangy reds, etc., of certain vintages of CRTs are not so much from the phosphor differences as from the chroma demod / matrix differences as manufacturers tried to get acceptable flesh tones. The reds in HDTV and PAL look much better than in NTSC even though the tubes use essentially the same phosphors. The ultimate greens and reds, of course, are NTSC on a 15GP22 - but its magentas and purples are paler because of the more cyan blue phosphor.

I work at a theatre, and I dont run old films there, either. Now, when I have a private party, and we run something from my collection...

Technicolor stopped doing its dye transfer process because it was expensive, and Eastmancolor had come a long way, if you can call it that, with its own color system. The studios were awfully cheap and were always looking for a cheap way out with color.

Just before Technicolor shut down and closed its dye transfer lines, Samuel Goldwyn, the movie producer, had new Technicolor negatives made of his color features dating back to the 1930's, and his color features shine today, with the exception of Guys And Dolls, and Porgy and Bess, which were done in Eastmancolor. When I worked in television, the new prints of Goldwyn titles we ran in 1976-77 looked better than anything we were getting from the other distributors.

The last major Technicolor dye transfer feature release was The Godfather II.

Look at some of the stuff that Turner Classic Movies plays. The Technicolor features tend to be just as vivid today as they were when new, provided that the original and printing negatives have been cared for properly, which many have.

AFAIK both PAL and NTSC use the same equations for generating Y, R-Y and B-Y

Y= 0.299R+0.587G+0.114B.
R-Y and B-Y then follow.

HD uses a different equation which is annoying. It's supposed to give a greater gamut.

The question of the masking matrix used in the camera is to get the colours to look right. Camera designers use a range of tricks such as detail out of green to get good pictures.

The BBC has done quite a bit of work on standardising the reproduction on LCD, Plasma etc which have totally different colour rendering to a CRT. It's hard to do accurate HD monitoring on a flat panel because on most of them the colours are all over the place. I think there are some decent flat panels now but the "gold standard" reference is still a CRT. Strictly not just any old CRT but one with phosphors of the correct chromaticities, or possibly a masking matrix in the monitor to correct them. THough this latter approach cannot give full gamut it's usually close enough.

Yes, NTSC and PAL use the same electrical equations for generating Y, R-Y and B-Y. However, the camera sensor responses are (or were, anyway) matrixed differently, NTSC for NTSC phosphors and PAL for EBU phosphors. In practice these days, it's hard to tell what is being done for NTSC, as the pictures are judged on modern displays, and the camera matrix may be fudged for the manufacturer's idea of "best" while receiver matrices were also fudged for the manufacturer's idea of pleasing results with modern phosphors. In the case of PAL and HDTV, there is a known (approximate, anyway) ideal matrix in the camera, and when there is a departure from it, the result can be known. Camera manufacturers still do as they please, but they are working to a standard display reference, which many physical displays do (or can) come fairly close to meeting (at least better than the large difference between NTSC P1 green and modern sulfide green).

HDTV went one step beyond PAL, using essentially the same phosphor primaries as PAL, but also recasting the electrical equations to match the actual luminance of the new phosphors when matching D65 white. This gives a minor improvement (decrease) in visibility of chroma noise/artifacts in desaturated colors, but doesn't make much difference in saturated colors, due to the gamma characteristic of displays. For this small improvement, we now have the nuisance of rematrixing when taking signals to/from HD/SD.