Line sequential color....

[ceebee23]

I have just been reading about the CBS vs RCA color war .... but it seems there was a third player in the game CTI. It had developed a line sequential color system.

Over at the ETF they have an article about it: http://www.earlytelevision.org/cti_color.html

But I was wondering if anyone here knew anything more..from what I have read they seem to have never really got the bugs ironed out.

Whatever the faults were seem to have stumped them or maybe they just did not have the cash that RCA and CBS had to invest in the war???

[old_tv_nut]

All of the above, I think.

The system was demonstrated in May 1950, and was eventually rejected (along with the RCA system) in favor of the CBS field sequential system. The Condon Committee report to the Senate stated that the picture quality was poor and was marred by serious line crawl even at low illumination levels.

The later record of the second NTSC indicates that no numerical data was available to calculate the severity of the line crawl or the factors that would affect it.

[ceebee23]

The system itself sounds a bit like SECAM, with line by line RGB but with SECAM of course you have the delay line system to resolve the issues probably present in the CTI system.

[dtuomi]

I think it might be worse than that. If I read that article correctly, didn't every line have a different color like R then G then B. If so woudn't that drop your resolution by 1/3, since they say it still uses the 525 line system?

David

[ceebee23]

I was thinking that ...I doubt it worked very well.... but we will never know!

[kx250rider]

I think the Sony Indextron works on that principle. Perfect convergence is the big plus on that system!

Charles

[John Folsom]

Sorry Charles, the Sony indextron system used a CRT with vertical RGB phosphor stripes, scanned horizontally, with index phosphor stripes used to "know" where the beam was as it scanned across the RGB phosphor stripes, so the proper RGB color signal could be time multiplexed onto the single electron gun.

[Robert Grant]

CTI Line Sequential was not like SECAM.
In Line Sequential color, each line represents one of the primary light colors (green, blue, red) whether the image has colors or not.
SECAM was actually more like NTSC than you might think. Like NTSC (and PAL), there was a luminance (or Y) signal that was compatible with monochrome recievers (in the case of SECAM, 625x25 then in service in Europe) that was not sequential and thus as flicker-free as monochrome TV.
The sequential refers to how the color subcarrier is transmitted. In SECAM, either R-Y or B-Y is transmittted as an *FM* video subcarrier on each line, and the subcarrier from the previous line is saved by a delay line (hence the "a memoire") and carries the opposite signal (B-Y or R-Y) to the color matrix, presenting the matrix with luminance, R-Y and B-Y (from which all colors can be mathematically derived) on each line. This gives SECAM (and, BTW, PAL) less "color resolution" in the vertical plane than NTSC, but, like horizontal color resolution, was deemed not-as-critical as lunimance resolution.
One disadvantage of SECAM is that it does not work well with character generators, or mixing of video. In SECAM countries, video production is generally done in RGB and only encoded into SECAM at the transmitter.

Rob

[wa2ise]

Originally Posted by John Folsom

Sorry Charles, the Sony indextron system used a CRT with vertical RGB phosphor stripes, scanned horizontally, with index phosphor stripes used to "know" where the beam was as it scanned

A big problem with this scheme was that the electron beam could never go to full black. Then the system would lose track of what strip it would hit once it came out of a black area of the image. It would look like an LCD display, with dark grey blacks...

[oldtvman]

I still think the whole issue of color television would make a great HBO special like band of brothers or john adams

[NowhereMan 1966]

Originally Posted by oldtvman

I still think the whole issue of color television would make a great HBO special like band of brothers or john adams

Maybe we could get Ken Burns to do it. I remember in 1992, he did a documentary on the three main men who developed radio, David Sarnoff, Edwin Howard Armstrong and Lee DeForest. I think it was called "Empire of the Air."

[jhalphen]

Hi to All,

A French TV director & myself have been working since 3 years on a script telling the saga about how the three major color systems conquered the world. We wanted the program to be ready for the 50th anniversary of color TV. We called it "Color Wars".

Right now, the project is shelved because no French documentary production co. nor TV network would fund the show. We lost one year between undecided companies & admin. red tape with the state TV networks.

General comment was: "it's interesting, but this project needs multi-country funding, we can't/won't do it alone".

Having much US content in the program (RCA, CBS, NTSC,..) we wanted to approach the Discovery Channel, but from Europe, all projects are funneled into Discovery UK who decides what is eventually submitted to the US program choice unit.

Oh well, we had fun writing it...

Best Regards

jhalphen
Paris/France

[yagosaga]

Hi Jerome,

it is a pity that you don't find a funding for such a project. But perhaps this might be of interest: here in Germany, a three parted tv saga is still in production which tells the story of prewar and early postwar television technique. It is based on a postwar attempt to produce the prewar E 1. A complete television assembly line from the late 1940s and early 1950s is just under construction. Due to the fact that no production hall still exists in Germany, the saga will be produced in the previous Eastern Bloc. The saga will be aired in three parts, each with 90 minutes.

BTW: Do you have an early French SECAM color tv set? I am currently working on the Color 20, and I could get it into working condition with a French PAL to SECAM converter.

Kind regards,
Eckhard

[ceebee23]

Rob,
thanks for the info on CTI vs SECAM... I guessed as much ... the reality would be that the CTI would have suffered from substantially reduced resolution both for color and monochrome viewers, apart from any other issues.

[jhalphen]

Hello Eckhard,

Thanks! for the info on the German TV series. Please tell us when it airs, as many Euro-readers of AK receive the German Sat channels on Astra (i do).No Early SECAM set, no space. Had a 1968 model given to me second hand in 1972, this was my first tube color TV. Dad gave it away when i moved.

PAL --> SECAM transcoders were/are plentiful in France because so many people had PAL camcorders. We have tested most of the popular models, and they all generate the important SECAM "Bottles" i.e. the color ident signal in the vertical interval.

Many of us run the first French Trinitron (KV-1220DF/KV-1221DF) from a DVB-T tuner (18 FTA channels) then a transcoder to get all 18 channels in color on the Sony.

The section here on French E-Bay filters out "transcoders" in the camcorder section:

http://photo-video.search.ebay.fr/tr...Z1QQsofocusZbs

The second link shows one of the popular models of transcoders, the Sony SFR-1000

http://cgi.ebay.fr/SONY-SFR-1000-tra...QQcmdZViewItem

If you don't feel comfortable dealing with French E-Bay sellers, i can buy one for you. If you want me to do this, please quote your max bidding amount (here or via MP)

Also interesting about the Sony 1220:
- Christophe G. developped a SCART RGB input mod
- Bruno P. has written some stuff on how to force 1st generation SECAM V. Ident color killers to "stay open all the time". This deals mainly with Philips Group color decoder IC chips: TCA-640/650/660, I have all this on file, yours for the asking.

Best Regards

jhalphen
Paris/France