Baird's Telechrome colour TV system.

[FERNSEH]

J L Baird's first 600 line colour TV system used only two colours, cyan and magenta. I have read that the results from this two colour system were surprisingly good. Could this idea be suitable for an experimental low definition colour system, say 60 or 120 lines? You would need only two narrow bandwidth channels for transmission.
What would the rendition of the mono picture be like?

DFWB.

[murphyv310]

Interesting David.
What about using one of those 32 line kits and re-drilling the Nipkov disc with 60 or more holes and introducing alternate cyan & magenta filters in the holes, surely a simple camera could be built?
Trevor

[FERNSEH]

Originally Posted by murphyv310

Interesting David.
What about using one of those 32 line kits and re-drilling the Nipkov disc with 60 or more holes and introducing alternate cyan & magenta filters in the holes, surely a simple camera could be built?
Trevor

Hi Trevor,
That's something we could consider.
I remember reading an article in a late 1950s Practical Television magazine about a mechanical colour TV system. I'll look for it when I return home.
Sixty lines will produce quite good pictures.

David.

[Andy Green]

Originally Posted by FERNSEH

What would the rendition of the mono picture be like?
DFWB.

This site http://www.widescreenmuseum.com/oldcolor/ with many examples of early colour film processes, many using two colour processes might give an idea. The whites always look a little orangey to me, and so I would expect that a monochrome picture would have an orange tint.

I did discover a very interesting reference to Edward Land's accidental experiment that showed that full colour could be achieved sometimes by only reproducing two colours - (provided three were originally used in the camera) one experiment used two slightly different yellows!
see http://www.greatreality.com/Color2Color.htm

[Panrock]

You probably already know I built a colour NBTV system, and this originally started out as two-colour. Results were quite acceptable, though because I was also synthesising green in the monitor from a mixture of the red and blue incoming signals, the system would confuse greens and purples. Since then, having obtained a red-sensitive photomultiplier and a dichroic block from kind members of this forum, I've upgraded to full colour.

Talking of 60/120 lines, as it happens I'm now converting the system for 80-lines (full colour stereo). The discs are now finished.

Steve

[FERNSEH]

Originally Posted by FERNSEH

I remember reading an article in a late 1950s Practical Television magazine about a mechanical colour TV system.

The article appeared in the July 1959 Practical Television. It described the construction of a closed circuit colour TV system, it was a sequential system without any moving parts. MW6/2 projection CRTs were employed at both end of the system. Two colours were employed in the system and was capable of operating with three colours. A glass core Faraday cell is used.
The writer demonstrated his apparatus at the Television Society's Exibition in March 1958. Technical details were given in the Journal of the Television Society, October-November 1958.

DFWB.

[peter_scott]

See.. http://www.ambisonic.net/bairdcp.html

[FERNSEH]

Hi Peter,
I wonder if the picture was generated from Mr. Baird's two colour system? Magenta and Cyan.

DFWB.

[Aerodyne]

Fascinating stuff, Peter, demonstrating once again that Baird wasn't the failure he is sometimes made out to have been. I once called him a near-genius and with the telechrome and his other colour experiments, I see no reason to change my opinion. A clever and highly inventive man who struggled with poor health throughout his sadly shortened life. Where's the statue?
-Tony

[jhalphen]

Hello Gentlemen,

More TeleChrome pictures scanned from the brochure "Seeing by Wireless" given to me by a retired gentleman from Quantel Broadcast.

Best Regards

jhalphen
Paris/France

[ppppenguin]

If the telechrome tube looks vaguely familiar, that's because it's based on a mercury arc rectifier bulb. I believe the bulbs were blown specially by the Hewittic company, one of the largest makers of mercury arcs.

[Aerodyne]

The principle of using two colours to create a reasonable 'full' colour image was around in photographic terms long before used it. The movies made by William Friese-Greene are a good example of possibly the earliest attempt (early 20th C). In the 1930s, two-strip Technicolor was used for some film presentations, notably cartoons - I believe 'Popeye' was an early recipient (Disney held some kind of right of usage for three-strip). It was typical of Baird that he took an existing idea, adapted it for his electronic purposes and succeeded in creating the first colour television image*, working virtually alone and always under-funded. Brilliant man.
-Tony
*As far as I know!

[dave walsh]

I think you are exactly right on this Tony. I met a chap in 1971 who told me about his 1936 colour set and I didn't really believe him. It was probaly that sort of cinematic image. More Baird awareness seems to be developing all the time. Without going too OT I've just e-mailed Malcolm Baird in Canada re the demolition of Baird Court in Bexhill. The developer has now agreed to name one of the replacement blocks [which at least have the same style] Baird Court again and put up a plaque! Bit of a victory for the diplomatic approach. Dave

[Aerodyne]

I'm very pleased to hear of that small victory, Dave. Maybe a new thread should be started on the best way that Britain (hasn't yet but should) honour JLB.
-Tony