In message , at
04:28:26 on Tue, 17 Mar 2015, whisky-dave
remarked:
Yes, but those changes are much slower than the backlight current
which is changing as the scenes change with the TV content.

My computer is far faster than my TV screen.

The rate at which the screen content changes isn't.

400 FPS on my TV is faster then 60HZ.

That isn't the rate at which the screen content changes.

and what do yuo think the backlight is doing then.

Working harder when the scene being shown was shot at night, less hard
when there's lots of white in it.

another vairiable, burning a DVD which I know takes an extra 5W of
power
which obviously all comes from the household's total consumption,

Yes, but again, much more slowly than TV scene changes.

Irrelivant.

That is how you work out what you are seeing current
wise is due to.

so what is this current ?

Driving the backlight.

--
Roland Perry

On Tuesday, 17 March 2015 12:56:38 UTC, Roland Perry wrote:
In message , at
04:28:26 on Tue, 17 Mar 2015, whisky-dave
remarked:
Yes, but those changes are much slower than the backlight current
which is changing as the scenes change with the TV content.

My computer is far faster than my TV screen.

The rate at which the screen content changes isn't.

400 FPS on my TV is faster then 60HZ.

That isn't the rate at which the screen content changes.

and what do yuo think the backlight is doing then.

Working harder when the scene being shown was shot at night, less hard
when there's lots of white in it.

and what exactly happens when the screen works 'harder' ?


another vairiable, burning a DVD which I know takes an extra 5W of
power
which obviously all comes from the household's total consumption,

Yes, but again, much more slowly than TV scene changes.

Irrelivant.

That is how you work out what you are seeing current
wise is due to.

so what is this current ?

Driving the backlight.

Yes I want to know what magnitude this current is or what value it is.
without knowing this you won't get anywhere.

so what current does a backlight use in a TV .

In message , at
06:38:05 on Tue, 17 Mar 2015, whisky-dave
remarked:

Working harder when the scene being shown was shot at night, less hard
when there's lots of white in it.

and what exactly happens when the screen works 'harder' ?

The backlight gets brighter and as a result they can claim a better
dynamic contrast ratio because scenes which would otherwise look like a
sea of mud have some detail visible in them.

another vairiable, burning a DVD which I know takes an extra 5W of
power
which obviously all comes from the household's total consumption,

Yes, but again, much more slowly than TV scene changes.

Irrelivant.

That is how you work out what you are seeing current
wise is due to.

so what is this current ?

Driving the backlight.

Yes I want to know what magnitude this current is or what value it is.
without knowing this you won't get anywhere.

so what current does a backlight use in a TV .

I posted some numbers a few days ago, measured from my clamp-on device
at the electricity meter (which transmits the result every 4 second to a
little box I have on my desk). Somewhere in the range 30-40 watts out of
about 100 for the TV as a whole.

--
Roland Perry

"Roland Perry" wrote in message
...
In message , at 05:31:00 on Tue, 17 Mar
2015, john james remarked:
There is. You take the "pattern" from a TV programme currently being
broadcast, and subtract it from the total. You ten see if what remains
matches any of the other TV programmes currently being broadcast.

If it doesn't batch, then try a second TV programmes... iterate until
you find two whose patterns do add up to the total.

Its a bit more difficult than that..

different TVs take different times to decode the signal to put on the
display.

That's trivially taken account of when matching up the patterns.

No it isn't, particularly when you only have 4 second samples of the
total house current.

We aren't looking for picture brightness altering second by second. More
from one shot to another.

Trouble is that when you don't know when the shots change,
you have to sample the total house consumption at a decent
rate to be able to work out the backlight level for each shot.

And smart meters used by electricity supply authorities
do not sample at anything like a 4 second rate anyway.
They in fact actually integrate the total current consumption.

different TVs have different response times for the backlight.

That will only affect the amplitude of the peaks/troughs, not their
size.

But it does mean that you can't just add every pair of channels broadcast
and see which matches the pattern you see on the house current.

You can try every pair until you get one which matches close enough.

No you can not when the two TVs are not identical designs.
If you can't assume identical TV designs, you don't even know
how to add to the two channel candidates together to get the
total of the two backlight currents to compare with the total
house current.

In practice you are actually eliminating the ones which don't match at all
(for example two channels where the picture is simultaneously dark, but
the current consumption indicate that at least one is bright).

But you can't even do that when the smart meter integrates
the total house current and only reports every 15 mins or so.

And there are those who check the other channels during ad breaks too.

See below - although add breaks in the UK are only 4 minutes, four times
an hour, and there's plenty of programme material in between to use as a
comparator.

Cut the ad breaks are not synchronised, so you can't even work out
when a particular channel is in an ad break even if you did have the
total house current every 4 seconds, and you don't have anything
like that.

In fact you'd only be trying to do the comparison during the
programme segments because different regions of the country have different
advertisements.

But there is no way to work out when it is an ad break.

It's claimed to be a 100% solution.

Presumably you meant "It isn't"

Yes.

So in practice its going to be quite hard to tell what TV programs you
are watching even if the smart meter could collect the data and send it
somewhere to be analysed which is going to be difficult as they use SMS
messaging and not the internet and the GSM control channel would be
swamped very quickly if a few meters started sending SMS every second.

The data can be batched up and sent later, but how long will smart
meters be using 20th Century comms when they are sat in the same under
the stairs cupboard as the ADSL router?

The point is that is how they work, so can't be used to snoop on what
you are watching when you have more than one TV used at once or
even just one when you are doing that with every smart meter.

It's not for snooping on everyone at once.

Its even less likely that say MI5 will be snooping on a particular
house to see who is watching the latest footage about ISIS avidly.

And the smart meters don't provide anything like enough data to
do that anyway.

In fact it's not really about snooping on anyone's TV schedule.

There is no other reason to try to work out what is being watched
on the TVs in the house.

I think you've lost sight of the original proposition that "IF (as you
can) you can tell what TV programme someone is watching,

No evidence that you can do that even with one TV given what
data the smart meter does provide to someone outside the house.

you can also
tell whether they've got other appliances like deep freezes,

You can do that even if you can't work out what is being watched
on the TV.

and hence
how much such appliances are taking; and you can tell what time someone
gets up in the morning etc).

You can do that trivially my just watching when the total house current
increases in the morning as they get up, turn the light(s) on and do other
stuff like have a ****, and put the jug on to have something to drink etc.

Even with someone like me that doesn't drink anything hot at all first
thing in the morning, its easy enough to see when I cook the toast.

Think of it like saying "if I can slip a bit of 200gsm card through this
gap in the window frame then there's going to be a draught when the wind's
blowing", and then everyone pitching in with objections like:

Only if the wind's blowing from that direction
Not if the gap still has the bit of card in it
I only have 100gm card and putting two of them in the gap isn't the same
Who wants to put a bit of card in *everyone's* window anyway

I've never been into analogies, they don't help with the question
of whether its actually possible to work out what someone is watching
on two TVs given the data that can be obtained from a smart meter.

"Roland Perry" wrote in message
...
In message , at 04:57:25 on Tue, 17 Mar
2015, john james remarked:
If you have one TV whose contribution to the power consumption is:

*** *** **** **** *** *** ***
*** *** **** **** *** *** ***
-----------------------------------------

and another whose contribution is:

* * * * ********* ************ * * *
* * * * ********* ************ * * *
* * * * ********* ************ * * *
-----------------------------------------

then the total is:

* * * ***** ** *** ** * *
* * * ***** ** *** ** * *
* * * * ********* ************ * * *
*** * *** ********* **************** ***
*** * *** ********* **************** ***
-----------------------------------------

But there is no way to go from the last one to the first two.

There is. You take the "pattern" from a TV programme currently being
broadcast, and subtract it from the total.

You can't do that when the total house power
use is only measured every 4 seconds.

You ten see if what remains
matches any of the other TV programmes currently being broadcast.

If it doesn't batch, then try a second TV programmes... iterate until
you find two whose patterns do add up to the total.

Just not feasible with 100 or more broadcast channels and a
4 second sample time of the total house power consumption.

I'd expect to be taking perhaps 100 measurements of the house,

Smart meters don't provide samples of the current consumption
of the house, they integrate the total current consumption and
report that at a few instances a day.

and
obviously having some central apparatus taking 4-second samples from all
the TV channels to compare those with later.

"whisky-dave" wrote in message
...
On Monday, 16 March 2015 18:10:11 UTC, john james wrote:
"whisky-dave" wrote in message
...
On Friday, 13 March 2015 18:03:47 UTC, john james wrote:
"whisky-dave" wrote in message
...
On Thursday, 12 March 2015 22:48:44 UTC, john james wrote:
"Capitol" wrote in message
...
john james wrote:

It is possible with just one TV but not with two.

I would phrase that as "may" be possible, but very unlikely.

It would be easy enough with just one as long as the TV
is showing a broadcast channel and has a backlight that
changes with what is on the screen.

But how will you measure the backlight current ?

From the change in the total house current.

So if I swtich on a 2kw heater then how does that indicate the current
change in the backligh of a TV ?

Its obvious that that heater has been
turned on from the change in the current.

How do you that it's from the heater and not the LED mains indicator or
teh fan.

From the size of the jump in current.

Of the LEDs on my washing machine flashing.

Ditto.

It wouldn't be that hard to separate that from the
other changes like with one of the other on/off loads
like the toaster or fridge or a hot plate coming on.

It's virtually impossible.

Very easy actually with something like say the toilet light
which has quite different time characteristics and power
characteristics than say the bedroom light etc.

rubbish.
Howq does a toilet light have differnt characteristics. ?

Its on for much shorter times more frequently than the other
lights. The only lights that come close are lights inside cupboards
and those don't aren't going to be the one that comes on every
morning in winter as people get up and have their first ****
or come on during the night as people ****.

Even with the small number of other appliances which
do vary the current they take in a continuous way, those
changes should be a lot slower than the backlight current
varying with the program content.

No they wouldn't, something switching off is switching off.

They aren't all simple on/off devices.

so how can you tell one from the other, you can't without some serious
kit measuring it at source.

It doesn't have to be done at the source, it can be
seen in the total house current, just because that
is varying much more frequently than with the
on/off devices like lights and toasters etc.


But I don't believe it would be possible to separate
out the individual backlight currents when you have
two TVs running at once showing different channels.

It wouldn't be possible to seprate the backlight current from almost
anything else in the house.

Wrong on the short term variations in that current alone.

You can't isolate them that's the problem.

Of course you can isolate them in the total house consumption.

But maybe you actually mean that with a smart meter you
don't actually have say the total house current every 4 seconds,
you actually have the total current integrated and reported back
at a rate that is nothing like every 4 seconds. Its certainly true that
with that it isn't even going to be easy to say work out exactly which
light has been turned on. Tho it will certainly be possible to work
out when at least one person has got up in the morning because
that is when the total house current starts to increase from the
minimum that is seen thru the night with an occasional spike
as someone gets up for a **** etc.

On further thought, I'm not now convinced that will even
be possible to work out what is being watched on a TV
that does modulate the backlight as the program content
changes, because all you have is the total house current
integrated, you don't have 4 second samples of the house
current. You do with the consumer addon meters that
Roland has, but the smart meters used to charge you for
the power you have used don't do it like that because
there is no point in sampling every 4 secs with those,
and there is no way to get that data out of the house
anyway, so they don't bother to collect it like that.

"whisky-dave" wrote in message
...
On Monday, 16 March 2015 18:16:40 UTC, john james wrote:
"whisky-dave" wrote in message
...
On Friday, 13 March 2015 19:30:12 UTC, john james wrote:
"whisky-dave" wrote in message
...
On Friday, 13 March 2015 12:56:31 UTC, Roland Perry wrote:
In message ,
at
04:05:22 on Fri, 13 Mar 2015, whisky-dave
remarked:
It is possible with just one TV but not with two.

I would phrase that as "may" be possible, but very unlikely.

It would be easy enough with just one as long as the TV
is showing a broadcast channel and has a backlight that
changes with what is on the screen.

But how will you measure the backlight current ?

It's between 1/3 and 2/3 (depending on the viewed content) of the
set's
overall consumption.

I'll ask again how will you measure the *backlight* current.

Unless I'm very much mistaken there's a meter
looking at the household's total consumption - one contributor to
which
is the TV.

So on the TV you have a silent B&W movie and next is the lastest
action
film.

As the volume goes up and down this also changes the current
consumption
of the TV.

Not by as much as the backlight changes with TVs that change
their backlight current with program content light levels tho.

The backlight current doesn't change anywhere near the amount you think
it
does.

It does actually and that is easy to measure to prove that.

So show me the results......

I don't have a TV that varies the backlight with what's show on the
screen. My TV is a gigantic glass tube TV than hasn't even been
turned on for maybe 8 years now. I don't watch any TV live, I watch
what the PVR records on one of the 24" wide screen LED monitors
on the desktop which does everything, including being the PVR.

Backlight currents have reduced by about 50% in the
last 2 years so all your reesults will be worng anyway.

What ? All that matters is that they vary with what is on the screen.

Also while watching the TV I might be using my computer increasing
teh brighness of the screen the power consuption nof my iMac almost
doubles and almost doubles again if I push teh grahics processor.
Yep
I've had 400 FPS on my retina 27 inch imac, that's when the fan
kicks
in,

Yes, but those changes are much slower than the backlight current
which is changing as the scenes change with the TV content.

My computer is far faster than my TV screen.

The rate at which the screen content changes isn't.

400 FPS on my TV is faster then 60HZ.

That isn't the rate at which the screen content changes.

and what do yuo think the backlight is doing then.

It doesn't vary at anything like that rate because what
is on the screen doesn't vary at anything like that rate.


Rubbish.


another vairiable, burning a DVD which I know takes an extra 5W of
power
which obviously all comes from the household's total consumption,

Yes, but again, much more slowly than TV scene changes.

Irrelivant.

That is how you work out what you are seeing current
wise is due to.

so what is this current ?

Varies with the design of the TV obviously.

and the washing machine cycle changes,
again changing total current consumnption,

Yes, but again, much more slowly than TV scene changes.
Those are just a few steps in the total house consumption.

if I open the fridge/freezer a light comes on.

Yes, but again, that is just a step change,
just like other lights being switched on.

they are all step changes so are the 7-segment displays on my clock and
washing machine.

And the change in the backlight current

what is this change ?

with a TV that
changes the backlight with the screen content isn't.

isn't what ?

Isn't a step change.

When my landline phone takes a message that
also takes more current, even the ringing would.

Again, both with quite characteristic waveforms.

No where near enough to be measurable by a smart meter.

The phone never rings for that long compared with the TV.

it doesn't have to, donl;t forget you're only sampling what curretn the
meter is reading in a fraction of a second.

That isn't how the electricity supply authority smart meters work.

They integrate the current over time because that is what you pay for.

"whisky-dave" wrote in message
...
On Tuesday, 17 March 2015 12:56:38 UTC, Roland Perry wrote:
In message , at
04:28:26 on Tue, 17 Mar 2015, whisky-dave
remarked:
Yes, but those changes are much slower than the backlight current
which is changing as the scenes change with the TV content.

My computer is far faster than my TV screen.

The rate at which the screen content changes isn't.

400 FPS on my TV is faster then 60HZ.

That isn't the rate at which the screen content changes.

and what do yuo think the backlight is doing then.

Working harder when the scene being shown was shot at night, less hard
when there's lots of white in it.

and what exactly happens when the screen works 'harder' ?

The TV takes more current, to make the backlight brighter.

another vairiable, burning a DVD which I know takes an extra 5W
of
power
which obviously all comes from the household's total consumption,

Yes, but again, much more slowly than TV scene changes.

Irrelivant.

That is how you work out what you are seeing current
wise is due to.

so what is this current ?

Driving the backlight.

Yes I want to know what magnitude this current is or what value it is.

You can see that the maximum and minimum current is.

without knowing this you won't get anywhere.

so what current does a backlight use in a TV .

Varies with the design of the TV.

On 17/03/2015 12:48, Roland Perry wrote:
In message , at
04:28:26 on Tue, 17 Mar 2015, whisky-dave remarked:
Yes, but those changes are much slower than the backlight current
which is changing as the scenes change with the TV content.

My computer is far faster than my TV screen.

The rate at which the screen content changes isn't.

400 FPS on my TV is faster then 60HZ.

That isn't the rate at which the screen content changes.

and what do yuo think the backlight is doing then.

Working harder when the scene being shown was shot at night, less hard
when there's lots of white in it.

Its the opposite, its brighter when the scene is bright.

On 17/03/2015 18:58, john james wrote:


"whisky-dave" wrote in message
...
On Monday, 16 March 2015 18:16:40 UTC, john james wrote:
"whisky-dave" wrote in message
...
On Friday, 13 March 2015 19:30:12 UTC, john james wrote:
"whisky-dave" wrote in message
...
On Friday, 13 March 2015 12:56:31 UTC, Roland Perry wrote:
In message
, at
04:05:22 on Fri, 13 Mar 2015, whisky-dave
remarked:
It is possible with just one TV but not with two.

I would phrase that as "may" be possible, but very unlikely.

It would be easy enough with just one as long as the TV
is showing a broadcast channel and has a backlight that
changes with what is on the screen.

But how will you measure the backlight current ?

It's between 1/3 and 2/3 (depending on the viewed content) of the
set's
overall consumption.

I'll ask again how will you measure the *backlight* current.

Unless I'm very much mistaken there's a meter
looking at the household's total consumption - one contributor to
which
is the TV.

So on the TV you have a silent B&W movie and next is the lastest
action
film.

As the volume goes up and down this also changes the current
consumption
of the TV.

Not by as much as the backlight changes with TVs that change
their backlight current with program content light levels tho.

The backlight current doesn't change anywhere near the amount you
think it
does.

It does actually and that is easy to measure to prove that.

So show me the results......

I don't have a TV that varies the backlight with what's show on the
screen. My TV is a gigantic glass tube TV than hasn't even been
turned on for maybe 8 years now. I don't watch any TV live, I watch
what the PVR records on one of the 24" wide screen LED monitors
on the desktop which does everything, including being the PVR.

Backlight currents have reduced by about 50% in the
last 2 years so all your reesults will be worng anyway.

What ? All that matters is that they vary with what is on the screen.

Also while watching the TV I might be using my computer increasing
teh brighness of the screen the power consuption nof my iMac almost
doubles and almost doubles again if I push teh grahics
processor. Yep
I've had 400 FPS on my retina 27 inch imac, that's when the fan
kicks
in,

Yes, but those changes are much slower than the backlight current
which is changing as the scenes change with the TV content.

My computer is far faster than my TV screen.

The rate at which the screen content changes isn't.

400 FPS on my TV is faster then 60HZ.

That isn't the rate at which the screen content changes.

and what do yuo think the backlight is doing then.

It doesn't vary at anything like that rate because what
is on the screen doesn't vary at anything like that rate.


Rubbish.


another vairiable, burning a DVD which I know takes an extra 5W of
power
which obviously all comes from the household's total consumption,

Yes, but again, much more slowly than TV scene changes.

Irrelivant.

That is how you work out what you are seeing current
wise is due to.

so what is this current ?

Varies with the design of the TV obviously.

and the washing machine cycle changes,
again changing total current consumnption,

Yes, but again, much more slowly than TV scene changes.
Those are just a few steps in the total house consumption.

if I open the fridge/freezer a light comes on.

Yes, but again, that is just a step change,
just like other lights being switched on.

they are all step changes so are the 7-segment displays on my clock
and
washing machine.

And the change in the backlight current

what is this change ?

with a TV that
changes the backlight with the screen content isn't.

isn't what ?

Isn't a step change.

When my landline phone takes a message that
also takes more current, even the ringing would.

Again, both with quite characteristic waveforms.

No where near enough to be measurable by a smart meter.

The phone never rings for that long compared with the TV.

it doesn't have to, donl;t forget you're only sampling what curretn
the meter is reading in a fraction of a second.

That isn't how the electricity supply authority smart meters work.

They integrate the current over time because that is what you pay for.



They integrate the energy used over time because that is what you are
charged for. That changes depending on the voltage on the supply which
changes with demand and with things like solar flux acting on solar
panels nearby and on wind, etc.

In message , at 05:33:55 on Wed, 18
Mar 2015, john james remarked:

We aren't looking for picture brightness altering second by second.
More from one shot to another.

Trouble is that when you don't know when the shots change,

You do, because you are monitoring all the channels.

I've never been into analogies, they don't help with the question
of whether its actually possible to work out what someone is watching
on two TVs given the data that can be obtained from a smart meter.

The analogy is the other way round, if you can monitor the TVs, you can
also monitor the fridge/freezer.
--
Roland Perry

In message , at 05:36:18 on Wed, 18
Mar 2015, john james remarked:
I'd expect to be taking perhaps 100 measurements of the house,

Smart meters don't provide samples of the current consumption
of the house, they integrate the total current consumption and
report that at a few instances a day.

To do that they need to take lots of readings - rather than classic
analogue meters which inherently do the integration.

How often they send those individual readings back to base will depend
on how much they need to know.

These metering schemes are advertised as capable of telling the
householder how much power each of his appliances takes - so that the
householder can make decisions about buying more economical examples of
each one, or perhaps arrange that they are only powered-up off-peak. If
the local meter is doing that - they can send the answers back to base
too.
--
Roland Perry

"Roland Perry" wrote in message
...
In message , at 05:33:55 on Wed, 18 Mar
2015, john james remarked:

We aren't looking for picture brightness altering second by second. More
from one shot to another.

Trouble is that when you don't know when the shots change,

You do, because you are monitoring all the channels.

But you don't get the total house consumption at anything
like that sort of sampling rate. You ONLY get the integrated
power and that is only sent out from the smart meter at a
MUCH lower rate and so can never be used to even allow
you to work out what is being watched on a single TV.

I've never been into analogies, they don't help with the question
of whether its actually possible to work out what someone is watching
on two TVs given the data that can be obtained from a smart meter.

The analogy is the other way round, if you can monitor the TVs,

You can't.

you can
also monitor the fridge/freezer.

Yes, that can certainly be monitored.

"Roland Perry" wrote in message
...
In message , at 05:36:18 on Wed, 18 Mar
2015, john james remarked:
I'd expect to be taking perhaps 100 measurements of the house,

Smart meters don't provide samples of the current consumption
of the house, they integrate the total current consumption and
report that at a few instances a day.

To do that they need to take lots of readings - rather than classic
analogue meters which inherently do the integration.

Yes, but those readings never leave the smart meter.

How often they send those individual readings back to base will depend on
how much they need to know.

But it is never going to be feasible to send say the integral
every 4 seconds, there is nowhere near the comms bandwidth
available to do that.

These metering schemes are advertised as capable of telling the
householder how much power each of his appliances takes - so that the
householder can make decisions about buying more economical examples of
each one, or perhaps arrange that they are only powered-up off-peak.

Yes, but that data doesn't need to leave the house.

If
the local meter is doing that - they can send the answers back to base
too.

But not anything like the data rate necessary to allow a central system
to compare the waveform with what you get when you compare it with
the screen intensity and contrast levels with TV program content even
with one TV, let alone more than one.

In message , at 07:39:12 on Wed, 18
Mar 2015, john james remarked:
you can
also monitor the fridge/freezer.

Yes, that can certainly be monitored.

How does that work if the readings are integrated over time?
--
Roland Perry

"Roland Perry" wrote in message
...
In message , at 07:39:12 on Wed, 18 Mar
2015, john james remarked:
you can
also monitor the fridge/freezer.

Yes, that can certainly be monitored.

How does that work if the readings are integrated over time?

You can see the power per time period change.

In message , at 08:22:39 on Wed, 18
Mar 2015, john james remarked:
you can
also monitor the fridge/freezer.

Yes, that can certainly be monitored.

How does that work if the readings are integrated over time?

You can see the power per time period change.

What is the time period.
--
Roland Perry

In message , at 07:44:36 on Wed, 18
Mar 2015, john james remarked:

"Roland Perry" wrote in message
...
In message , at 05:36:18 on Wed, 18
Mar 2015, john james remarked:
I'd expect to be taking perhaps 100 measurements of the house,

Smart meters don't provide samples of the current consumption
of the house, they integrate the total current consumption and
report that at a few instances a day.

To do that they need to take lots of readings - rather than classic
analogue meters which inherently do the integration.

Yes, but those readings never leave the smart meter.

Today.

How often they send those individual readings back to base will
depend on how much they need to know.

But it is never going to be feasible to send say the integral
every 4 seconds, there is nowhere near the comms bandwidth
available to do that.

Today.

These metering schemes are advertised as capable of telling the
householder how much power each of his appliances takes - so that the
householder can make decisions about buying more economical examples
of each one, or perhaps arrange that they are only powered-up off-peak.

Yes, but that data doesn't need to leave the house.

So you agree the meter can work out which appliances are drawing what,
including two different TVs?

If
the local meter is doing that - they can send the answers back to
base too.

But not anything like the data rate necessary to allow a central system
to compare the waveform with what you get when you compare it with
the screen intensity and contrast levels with TV program content even
with one TV, let alone more than one.

See my previous comments about the reverse-analogy you are pointedly
ignoring.
--
Roland Perry