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  #46  
Old 02-20-2017, 11:11 AM
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dtvmcdonald dtvmcdonald is offline
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Its not just a lack of green. Its also a lack of magenta/violet.

This simply means that the I/Q or rather R-Y/Q balance is off seriously.

Look at the SPECIFIED type color bars with your scope and adjust per instructions. Alternatively, use R-G-B-Yellow-Cyan-Magenta bars and
adjust so bars containing a given primary all have the same height at
the CRT grids ... see CT-100 scope traces. Pay particular attention
to the R-Y gain, its non-intuitive.

If this fails, you have matrix resistor issues.
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  #47  
Old 02-20-2017, 12:04 PM
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Thank you dtvmcdonald.

"Its not just a lack of green. Its also a lack of magenta/violet."

What leads you to this conclusion?
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  #48  
Old 02-20-2017, 12:12 PM
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dtvmcdonald dtvmcdonald is offline
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Why too little magenta? First, cartoon characters tend to have lots of magenta and
violet ... the designers like the whole rainbow. Yours do have a rather drab violet. Second, the overall "look" is the
same as when my CT-100 (pre red gun illness or even now at low brightness)
is misadjusted with the wrong I (or R-Y) gain setting.
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  #49  
Old 02-20-2017, 01:19 PM
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Doug,

Okay, that is good to know. We will look into it. I would still like to see some screenshots of your CT-100 prior to the red gun problem, or direct me to the thread where you posted the shots. Thanks.
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  #50  
Old 02-22-2017, 05:27 PM
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Here are a few shots displaying magenta, purple and green on my 21CT55. They were captured yesterday on February 21, 2017 from an OTA broadcast on Decades TV of the 1955 Technicolor movie, "Gentlemen Marry Brunettes". The movie is showing its age in terms of quality but this is my magenta and green presently. Of course it varies from program to program.







Edit: I found this screenshot from a remastered CD shown on a modern television. Apparently my green is not to far off from what it should be.



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Last edited by etype2; 02-22-2017 at 06:11 PM.
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  #51  
Old 02-22-2017, 07:55 PM
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dtvmcdonald dtvmcdonald is offline
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Quote:
Originally Posted by etype2 View Post
Doug,

Okay, that is good to know. We will look into it. I would still like to see some screenshots of your CT-100 prior to the red gun problem, or direct me to the thread where you posted the shots. Thanks.
See attached pictures. The cartoons and girl with hat are off the air

Test pattern is RGB
+I -I +Q -Q

My avatar is also the CT-100
Attached Images
File Type: jpg _MG_4454s.jpg (58.2 KB, 33 views)
File Type: jpg _MG_4447s.jpg (79.4 KB, 32 views)
File Type: jpg _MG_4481s.jpg (42.1 KB, 33 views)
File Type: jpg _MG_5053.jpg (69.8 KB, 41 views)
File Type: jpg _MG_4611s2.jpg (69.1 KB, 34 views)

Last edited by dtvmcdonald; 02-22-2017 at 08:07 PM. Reason: use better picture
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  #52  
Old 02-22-2017, 08:25 PM
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Thanks for posting this. The red in Dorthy's lips is "redder" then my same screenshot. The girl with the hat shot, was that prior to your red gun problem? Looks well balanced.

Note: The first shot in my last post was done with the tint control set for overall best flesh tones on a majority of OTA programs. When I saw the dresses, I assumed they were magneta. It's possible that the dresses are really red.
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  #53  
Old 02-23-2017, 09:51 AM
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Might I make a suggestion, etype2?

Post some screenshots from the Eisenhower tape and "An Evening With Fred Astaire". Download the higgest quality copies from say YouTube and burn it to a DVD or stream it via a media server and STB to your 21-CT-55. Those are "known quantities", whereas a Technicolor film could have been sourced from an IB print, the negatives, an Eastman print, etc. Then there's the issue of color correction. For example, there are DVD copies of "The Wizard of Oz" that are sourced from an IB print, and at least two versions sourced from the negative scans but color corrected differently. If you use the Eisenhower tape though, we can all look at the YouTube clip and compare that to the screenshots. It's one less variable to contend with.

Just an idea.
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  #54  
Old 02-23-2017, 02:41 PM
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Ben,

I have watched both programs on YouTube. Thankfully Chris Trexler has preserved the entire Fred Astaire special complete with commercials in one clip for all of us to enjoy and many thanks to the late Ed Reitan and his colleagues for restoring the Astaire tape in the first place.

What is STB? Your suggestions are good ones. BTW, We were lucky to win Ed Reitan's Worthington CTC-7 several years ago at the ETF convention. The Worthington first introduced in 1958 was the same year as the Astaire special. We would like to pay tribute to Ed Reitan and play that special on his set, (We are just the custodian for now) then make a video of our own and publish it on YouTube.

So yes, we would very much like to take up your suggestions. Thanks.
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  #55  
Old 02-23-2017, 03:10 PM
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STB= set top box

You can use a Raspberry Pi with an XMBC-centric distribution as a set top box. Then run an XMBC server and stream the data over your network. Or, just burn the videos to a DVD and play them back through a decent DVD player connected to a decent RF modulator.

The XMBC solution is more elegant though because you can turn the actual color burst on and off, etc. Much better for diagnostic purposes. And it requires only the use of your existing network, either wired or wireless. Fewer coax cables strung about.

Both specials would make subjectively "better" programming for comparison purposes in my opinion. I don't know how "The Wizard of Oz" became a sort of pseudo-standard for demonstrating early color sets, but I wish it hadn't. Other, better, options exist.
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  #56  
Old 02-23-2017, 05:51 PM
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Quote:
Originally Posted by etype2 View Post
We were lucky to win Ed Reitan's Worthington CTC-7 several years ago at the ETF convention. The Worthington first introduced in 1958 was the same year as the Astaire special. We would like to pay tribute to Ed Reitan and play that special on his set, (We are just the custodian for now) then make a video of our own and publish it on YouTube.
I'll be doing nearly the same thing with his Gilfillan prototype, if and when I ever get around to making it work.
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  #57  
Old 02-23-2017, 08:12 PM
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dtvmcdonald dtvmcdonald is offline
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The correct method for comparing color rendition is as follows.

It requires a modulator and a box, usually a Blu-Ray player, that will
play from memory sticks.

1) Obtain suitable jpg file of subjects that illustrate want you think matters.

2) copy those to your memory stick.

3) play them to your TV.

4) take pictures of the TV

5) transfer the pictures to the computer the files came from

6) one at a time, open the pictures of the TV in a photo editor
on the computer. At the same time, have the picture showing on the TV,
set just as it was when taking the picture.

7) edit the photo on the computer until it looks just like the TV
(that is, the image on the computer screen looks like the TV)

8) save the edit picture.

You then upload both the original picture you played on your TV
and the edited picture you took off the TV

Because you edit the picture of the TV on the computer to match the TV,
if you show the original and the TV picture on the same computer,
you will see the difference the TV made. This will also be true
of doing the comparison on ANY computer since you will have the
two files to compare.

There are three pairs of pictures made using this method
here:

http://videokarma.org/showthread.php?t=262176&page=6

One of them is three bicycles, another is purple flowers.

I've attached images of a standard test pic.

Doug
Attached Images
File Type: jpg 800test.jpg (74.1 KB, 31 views)
File Type: jpg 800testorig.jpg (135.4 KB, 29 views)

Last edited by dtvmcdonald; 02-23-2017 at 08:24 PM.
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  #58  
Old 02-23-2017, 09:44 PM
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Doug,

Thank you for this great step by step explanation. I now get it. I resisted you in the past because I misunderstood what you were saying. You were talking about Photoshop and I heard manipualation. Manipulation to me is photo editing to make the photo look better then it was and that's still true. In the context of what you are now saying it's not manipulation. I don't have a computer at the moment, so I'm using an iPad Air.

In my post#50 above, photos 3,4 and 5, is in a way the same test, but we did it backwards. We took all photos first. Then we got the idea to see if we could see pristine photos of the same movie. By luck and pure chance, we found a near identical pristine widescreen screenshot of my image #3. You can see it comes close to the original pristine photo but the roundie 21CT55 cuts off almost 50% of the image! If We had the pristine photo first, we could have adjusted the saturation a bit lower on the 21CT55.

I'm hearing rumors of a new iMac coming soon to replace a now two year old model. We will purchase at that time. We moved to a new home last May and we didn't bother hooking up the old PC because it's too slow.
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Last edited by etype2; 02-23-2017 at 09:53 PM.
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  #59  
Old 03-01-2017, 06:23 PM
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Just an FYI for anyone interested, I downloaded the highest resolution copies of the Edsel Show tape, the WRC tape, and an evening with Fred Astaire from Youtube. I then used some light denoise, corrected an issue in the WRC tape chroma, scaled it down with a top notch scaling algorithm, reencoded/remuxed it to a DVD compliant TS stream (2 pass, VBR), built a little DVD menu for it, and have the ISO for anyone interested.

It still looks like sh*t on a flat panel (like most SD material) but looks very nice on an analog set. Short of getting access to the whatever Ed Reitan and co. dubbed the specials to when they played back the tapes, my lightly cleaned copies are probably the best looking out there.

If you want it, PM me.
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  #60  
Old 03-01-2017, 07:02 PM
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Kevin Kuehn Kevin Kuehn is offline
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I think ya'll are way over thinking this. Just adjust the set so it's a respectable representation of the colors as you see them in nature, and boom you're done.
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