Westinghouse K840CK15 Restoration

[etype2]

Here is a link with more detail of the pixel structure of the 15GP22.

https://visions4netjournal.com/wp-co...CE28BDEC0D.png

https://visions4netjournal.com/wp-co...2471DDCC0.jpeg

[Electronic M]

Originally Posted by etype2

Here is a link with more detail of the pixel structure of the 15GP22.

https://visions4netjournal.com/wp-co...CE28BDEC0D.png

https://visions4netjournal.com/wp-co...2471DDCC0.jpeg

Pixel structure is an incorrect/inaccurate term if applied to CRT displays(phosphor dot structure in color and phosphor grain in monochrome are correct). One makes a digital images by creating a grid of boxes (known as pixels) that have a fixed position on the image both in the source and display devices and a specific light value corresponding to the image at that point.
There is no fixed position for a specific pixel of image on any CRT. The scanning in tube sets is not precise enough to achieve that. Any pixel of source info could end up being more than 1/4" off from it's last screen position on the screen between showings (based on things like line voltage, brightness setting, tube aging etc.)... Digital displays and video standards are designed to convey images as pixels all numerically fixed in space and light value, but analog video is designed to opperate as a field of rows of lines and image element position defined by timing relative to the line scanning sync pulses (and there's a lot of fudge factor in the analog system)...you can convert between the two but they are not the same... infact the more conversions one does back and forth the more error/loss introduced to the image.

If this wasn't a rare desirable set and you had the motivation you could modify the chassis to scan 1080i onto that phosphor screen and substantially increase the number of source pixel info placed onto the phosphor dots. In a monochrome set no information is lost doing this as most monochrome phosphor is fine grained enough that with good beam focus and scanning each pixel will be resolved...in color that pixel structure has to be mapped onto the phosphor dot matrix...it can be even if the phosphor dot matrix is courser than the pixel matrix of the source material being scanned onto it (the 15GP22 and 11SP22 in a portacolor both have much courser dot pitch than is ideal for NTSC while larger tubes have fine enough dot pitch to correctly resolve NTSC). When the dot matrix is too course a given pixel may not land on dots of all 3 colors and will not be accurately colored, and in extreme cases a few pixels could be resolved on a dot of a single color phosphor (in that case pixels would be lost in the border around each dot of phosphor) sets like the portacolor they try to bandwidth limit the video to smear pixel info together and hide the more annoying artifacts that this can cause....one could also do the opposite and make the dots much smaller than each pixel so each pixel [ or to use pre-digital video lingo the smallest image element the desiged video bandwidth and scanning system can support] one or more triad of phosphor (which is what CRT design engineers try to accomplish in most designs).

[etype2]

I agree, it is more accurate to say “dot” structure in this case. In the digital age, pixel is used (by me) :-) A lossy file can help prevent degradation after many conversions.

This image unscientifically demonstrates the difference on a 21AXP22 with a higher dot count per sq. inch. I had to enlarge the image more before the dots began to resolve. Overall the screen looks less granular and brighter then the 15GP22. Both tubes have about the same emissions.

https://visions4netjournal.com/wp-co...725F8CEDCF.png

[dtvmcdonald]

As I've said before, I have a CT100 chassis driving a modern fine pitch Trinitron using the RGB grid signals of the CT100.

The picture quality is very dramatically better than a 15GP22 because
of the finer pitch. Test patterns of B&W chirp patterns clearly
show the dropoff to a null at 3.6 MHZ and a small rebound above that,
as expected from the replacement "white coils" I used. This pattern never
gets find enough for the stripe pitch to be noticeable.

The thought of how awful it would be on a Portapotty CRT is fearsome to comtemplate.

[etype2]

Have you posted a screenshot of your conversion?

I have a Sony 36XBR960 with “Super” (Sony description) Fine Pitch. It’s rated for HD. I like it.

Edit: 34XBR960.

[dtvmcdonald]

Originally Posted by etype2

Have you posted a screenshot of your conversion?

Yes, its aground this forum somewhere.

Dorothy's dress is WHITE!

[etype2]

“Dorothy's dress is WHITE!”

Like this? :-) https://visions4netjournal.com/wp-co...81D2A459C.jpeg

[etype2]

I found two screenshots of your conversion here. http://www.videokarma.org/showthread.php?t=271626 A bit bright as you said. The second shot dose not resolve the blue squares on her dress. Very vibrant colors! Nice.

Edit: I just reviewed that sequence on the video. Very tough to resolve the blue checks from that distance from the camera with the resolution your dealing with. Just thought the fine pitch Trinitron could capture it.

[dtvmcdonald]

Originally Posted by etype2

“Dorothy's dress is WHITE!”

Like this? :-) https://visions4netjournal.com/wp-co...81D2A459C.jpeg

No. Her dress is blue where it should be white. It was also blue
on my late lamented 15GP22.

When I say white, I don't mean the checkered part. I mean the uncheckered part
above that. In person it looks even whiter than in the pics listed above.

[etype2]

“ No. Her dress is blue where it should be white.” .
Huh? The above photo shows a white blouse that is partly transparent with a blue and white checked dress. If I turned up the brightness the blouse would look whiter.

Maybe it’s a difference in monitors. My iPad Pro 2 is calibrated and covers 99% of DCI P3.

[etype2]

UPDATE, NOVEMBER 11, 2019
This video features snippets from the 1948 Technicolor movie, “The Red Shoes” as viewed on the *first color television in the world.

A young ballet dancer is torn between the man she loves and her pursuit to become a prima ballerina. The film won two Oscars and numerous other awards. Natalie Kalmus, the color consultant for the film and co- owner of Technicolor, believes this film to be their best work with Technicolor film processing. This film is one of my favorite classic’s because of its refined color palette. I think it presents well here, considering the age of the television and imaged on the first production color cathode ray tube. During the sequences, a fan can be heard droning in the background. It was installed to protect critical components on the chassis. After 45 days viewing this set after restoration, the set is stable, the tuner remains drift free and overscan on the 15GP22 is minimal for a color television from this era.

* The Admiral C1617A was the first color television offered for sale. The 1954 Westinghouse H840CK15 may have been the first color set sold.

Link: https://videopress.com/v/d1OgtjwN?autoPlay=1

[etype2]

UPDATE, NOVEMBER 11, 2019
This video features snippets from the 1948 Technicolor movie, “The Red Shoes” as viewed on the *first color television in the world.

A young ballet dancer is torn between the man she loves and her pursuit to become a prima ballerina. The film won two Oscars and numerous other awards. Natalie Kalmus, the color consultant for the film and co- owner of Technicolor, believes this film to be their best work with Technicolor film processing. This film is one of my favorite classic’s because of its refined color palette. I think it presents well here, considering the age of the television and imaged on the first production color cathode ray tube. During the sequences, a fan can be heard droning in the background. It was installed to protect critical components on the chassis. After 45 days viewing this set after restoration, the set is stable, the tuner remains drift free and overscan on the 15GP22 is minimal for a color television from this era.

* The Admiral C1617A was the first color television offered for sale. The 1954 Westinghouse H840CK15 may have been the first color set sold.

Link: https://videopress.com/v/d1OgtjwN

[etype2]

UPDATE, NOVEMBER 16, 2019
Continuing to audition classic movies on our newly restored 1954 Westinghouse H840CK15 with 15GP22 cathode ray tube. This video features snippets from the 1953 film, “Kiss Me Kate”. The film debuted just 3 months prior to the Westinghouse going on sale, the world’s *first* color television.

An ex-husband and wife team star in a musical version of “The Taming of the Shrew”, off-stage, the production is troublesome with ex-lovers’ quarrels and a gangster looking for some money owed to them.

The film was photographed using the Ansco color process and printed at the Technicolor lab in Hollywood. This film is a light hearted musical with comedic performances by James Whitmore and Keenan Wynn. Very colorful movie to demonstrate the performance of the *first* all electronic color television offered to the public.

* There were two other color televisions available prior to the Westinghouse H840CK15.

Link: https://videopress.com/v/T8xJgjmV

[Tom9589]

Is it my imagination that the sound and video are not in sync? The sound appears to be ahead of the video. Note the scene at about 5:33 where a vase is thrown from the balcony and the sound of the crash arrives before the vase hits the ground.

[old_tv_nut]

Originally Posted by Tom9589

Is it my imagination that the sound and video are not in sync? The sound appears to be ahead of the video. Note the scene at about 5:33 where a vase is thrown from the balcony and the sound of the crash arrives before the vase hits the ground.

I noticed some mismatch too.