B&W picture is bluish-green

[[email protected]]

When I watch the "oldies" tv channels, (This TV or Me-Tv) I noticed that
all those old Black and white programs are actually black, white, and
shades of gray. But when the Patti Duke show comes on every morning on
This-Tv, it's bluish-green tinted. It's only that show, all the other
B&W shows are really B&W. Some episodes of the Patti Duke show are more
tinted than others. Why is this?

Note, this is not just one tv set. I notice it on several tvs, and they
are different brand tv sets and converter boxes. They is hooked to
rooftop antennas.

 

[Jasen Betts]

When I watch the "oldies" tv channels, (This TV or Me-Tv) I noticed that
all those old Black and white programs are actually black, white, and
shades of gray. But when the Patti Duke show comes on every morning on
This-Tv, it's bluish-green tinted. It's only that show, all the other
B&W shows are really B&W. Some episodes of the Patti Duke show are more
tinted than others. Why is this?

Note, this is not just one tv set. I notice it on several tvs, and they
are different brand tv sets and converter boxes. They is hooked to
rooftop antennas.

possibly converted from film to digital and had the wrong lamp in the
converter?

 

[Tim Williams]

NTSC or digitalized?

I don't know if DTV supports monochrome the same way NTSC did. When an
NTSC signal doesn't contain a colorburst subcarrier, the chroma detection
is turned off and the set reverts to B&W operation -- tint would be
controlled by RGB balance and gain, but these will be correct in a
properly adjusted set.

I'd guess digital is always color and the actual color a B&W program has
depends on how it was transcoded. It's very easy to apply a filter to a
video stream these days, some may simply have different opinions of
"white".

Tim

 

[Phil Allison]

When I watch the "oldies" tv channels, (This TV or Me-Tv) I noticed that
all those old Black and white programs are actually black, white, and
shades of gray. But when the Patti Duke show comes on every morning on
This-Tv, it's bluish-green tinted. It's only that show, all the other
B&W shows are really B&W. Some episodes of the Patti Duke show are more
tinted than others. Why is this?

Note, this is not just one tv set. I notice it on several tvs, and they
are different brand tv sets and converter boxes. They is hooked to
rooftop antennas.

** You can always turn down the "color" saturation and get a B&W pic.

Wot a whinger....


..... Phil

 

[Gib Bogle]

When I watch the "oldies" tv channels, (This TV or Me-Tv) I noticed that
all those old Black and white programs are actually black, white, and
shades of gray. But when the Patti Duke show comes on every morning on
This-Tv, it's bluish-green tinted. It's only that show, all the other
B&W shows are really B&W. Some episodes of the Patti Duke show are more
tinted than others. Why is this?

Note, this is not just one tv set. I notice it on several tvs, and they
are different brand tv sets and converter boxes. They is hooked to
rooftop antennas.

As far as I'm concerned b&w TVs were never b&w. I noticed this one
night walking in the street - from the outside the flickering TVs in
peoples' houses looked bluish.

 

[Phil Allison]

"Gib Bogle"

As far as I'm concerned b&w TVs were never b&w. I noticed this one night
walking in the street - from the outside the flickering TVs in peoples'
houses looked bluish.

** That is an optical illusion created by the differing "colour temps" of
(1950s or 60s) incandescent street lighting and the daylight white of TV
screens.



..... Phil

 

[Gib Bogle]

"Gib Bogle"

** That is an optical illusion created by the differing "colour temps" of
(1950s or 60s) incandescent street lighting and the daylight white of TV
screens.

Interesting. Makes sense. I once had my mind blown by a talk given by
a guy from Polaroid, about the determining influence of context on
colour perception.

 

[Phil Allison]

"Gib Bogle"

Interesting. Makes sense. I once had my mind blown by a talk given by a
guy from Polaroid, about the determining influence of context on colour
perception.

** Oh yeah - human eyes quickly correct for varying ambient lighting
conditions, including the colour, so we see colours much the same as in
daylight.

OTOH a camera is a dumb animal and sees colour pretty much as it is.

Take a pic of someone standing under a leafy tree and they look greenish.



..... Phil

 

[spamtrap1888]

As far as I'm concerned b&w TVs were never b&w.  I noticed this one
night walking in the street - from the outside the flickering TVs in
peoples' houses looked bluish.

The P4 phosphor has a radiance peak at 450nm. See for example, Fig. 4
here:

research.opt.indiana.edu/Library/Fry91/Fry1991.pdf

 

[Gib Bogle]

"Gib Bogle"


** Oh yeah - human eyes quickly correct for varying ambient lighting
conditions, including the colour, so we see colours much the same as in
daylight.

On reflection ... some of the places where I observed TVs from outside
had no street lights. It was quite dark. Hmm.

 

[Phil Allison]

"Gib Bogle"

On reflection ... some of the places where I observed TVs from outside had
no street lights.

** But all the homes had incandescent lights on inside - so the same thing
happens.



..... Phil

 

[Gib Bogle]

"Gib Bogle"



** But all the homes had incandescent lights on inside ...

Maybe ... I can't remember.

 

[Gib Bogle]

"Gib Bogle"



** But all the homes had incandescent lights on inside - so the same thing
happens.

Maybe they did, I can't remember. But if the TV looks blue in
comparison with the incandescent lights from outside, why not from
inside too?

 

[Gib Bogle]

The P4 phosphor has a radiance peak at 450nm. See for example, Fig. 4
here:

research.opt.indiana.edu/Library/Fry91/Fry1991.pdf

I don't know enough about the subject to say for sure, but perhaps this
is the reason.

 

[Nemo]

This is not the answer to your question, but it is an interesting
historical thing about the development of colour TV.

Some 30 years ago a friend was watching old B&W reruns of The Outer
Limits and thought he could see colour in the opening credit sequence -
even though he was watching on a B&W TV. He wrote to the BBC techies to
enquire what was going on. They replied that at the end of the B&W era
TV / film techs had experimented with simulating colour by strobing the
intensity at certain frequencies, which fooled the eye somehow. It
worked, sort of, but then proper colour TV took off and it was not pursued.

 

[[email protected]]

All B&W (positive) film stock did not necessary have a completely
neutral tint. The human eye will quickly adopt to this, but a film
scanner will capture this tint if not properly compensated or closing
the chrominance channels.

I have also seen quite a few WW2 era B&W news films in TV
programs/DVDs with a distinct brownish tint, apparently for artistic
purposes. If the program also contained colour news clips, the use of
some brown tint was even more common, apparently to reduce the
difference between colour and B&W clips, a brownish B&W clip looks
like some old colour clip that has lost the blue colour during the
years .

NTSC or digitalized?

I don't know if DTV supports monochrome the same way NTSC did. When an
NTSC signal doesn't contain a colorburst subcarrier, the chroma detection
is turned off and the set reverts to B&W operation -- tint would be
controlled by RGB balance and gain, but these will be correct in a
properly adjusted set.

In SD digital luminance signal is sampled at 13.5 MHz, while the two
chrominance signals are sampled both at 6.75 MHz. The B&W material
should be contained in the luminance channel, while the two
chrominance channels should be empty, thus maximizing the luminance
throughput.

 

[SoothSayer]

I have also seen quite a few WW2 era B&W news films in TV
programs/DVDs with a distinct brownish tint, apparently for artistic
purposes.

It is called 'sepia' and I can't believe that you know so much about
video re-construction, but have no clue about image capture roots.