Seeing colour in a B&W film..

On Monday, 1 January 2018 17:15:22 UTC, Terry Casey wrote:

Never seen anything like that in a domestic set, very cost inefficient indeed. Why would they do it?
NT
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Ata guess - for stability of the picture.
--
from KT24 in Surrey, England

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On Monday, 1 January 2018 21:17:39 UTC, charles wrote:

t

ft

r

multipliers reduce EHT stability. They also, by introducing RC type time de lays, reduce the effectiveness of the usual practice in valve sets of letti ng B+ voltages waver all over the place, designing the set so everything co mpensates and the picture doesn't shift.
NT
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Nope, electric fences arent.

Nope the current isnt that high.

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On Sunday, 31 December 2017 21:00:14 UTC, NY wrote:

yes except i doubt they had smoothing, the CRT anode has significant capacitance.

no, for decades TVs used an EHT winding on the LOPTF that was fed to a tripler. I've never seen one use a mains fed large value multipler stack, and doubt it would work.

no, contact with TV EHT was survivable, if not fun. Not so for early sets though.

I've never seen that done.
NT
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On Sun, 31 Dec 2017 11:58:41 +0000, Harry Bloomfield wrote:

Yes, it was shown that certain flicker rates caused the brain to 'see' colour. An OXO commercial was shown and some people saw the gravy as brown and some as purple. It didn't catch on.
--
TOJ.

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Tomorrows World showed something like that in the late '60s. Sadly, the film was American and intended to be shown at 24fps. In the UK showing it 25fps gave completely different results to the script
--
from KT24 in Surrey, England

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Quite. Fooling the brain into thinking there is colour is an interesting trick. But unless consistent for everyone, a bit pointless.
--
*How do you tell when you run out of invisible ink? *

Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
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On Sunday, 31 December 2017 13:45:03 UTC, Dave Plowman (News) wrote:

It still has uses, or did in the B&W days, but only where the absolute colour value doesn't matter a hoot, which of course is mostly not the case.
NT
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I sometimes experience lemon tinted whites when watching B&W films on a modern TV, say when a character is wearing a white shirt - while all the other whites show up ok. Also sometimes the sky has a distinct lemon or mauve tinge.
There's a way around it by altering the settings although offhand I can't remember what it is. ISTR it may also be affected by the viewing angle.
michael adams
...
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Another variable throw into the mix: not all black and white films on TV are the same shade. The film base may develop a slight colour tint as it ages, which leads to greys that may be very pale mauve or very pale green. You'd think that when B&W films were transmitted on TV, they would set R=G=B so as to achieve pure, untinted B&W irrespective of the colour of the original film.
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On 31/12/2017 17:46, NY wrote:

They used to be something called a colour killer that locked the telly to monochrome when a monochrome prog was on. When it didn't work the picture would have spurious colours, usually flashing. It was most annoying.
Bill
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I realise that broadcasters used to turn off the colour carrier when a monochrome programme was broadcast, though I imagine towards the end of analogue TV, broadcast equipment might start to protest if the CSC was ever not present.
For digital, I'm surprised that the source material direct from the telecine doesn't have the three components set to equal values, long before it gets as far as the broadcast equipment.
Talking Pictures TV shows a lot of B&W material and there is often a colour cast - most noticeable when they change from one film to a trailer for another at an advert break.
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All down to costs. Everyone knows digital is perfect so can be used with no human intervention to check things.
If 'they' can't get something like audio levels somewhere near close when doing a transfer, not much hope for far more complicated pictures.
--
*If at first you don't succeed, try management *

Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
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Dave Plowman (News) wrote :

I would expect that part of the process to be automated, adjusted automatically for colour cast on a B&W film.
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In article
snipped-for-privacy@privacy.net says...

It will be, in the same way that analogue scanners and cameras were.
However, to produce the monochrome part of the picture, the three signals have to be combined in exactly the correct ratio which is 59% Green, 30% Red and 11% Blue.
TV signals were produced in digital form for years before DSO so the analogue signals produced from them needed to be in exactly the same proportions to avoid upsetting the colour balance.
--

Terry

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On Sun, 31 Dec 2017 11:58:41 GMT, Harry Bloomfield

http://dailym.ai/1YeTTF6 also
https://www.youtube.com/watch?v=3P8q_dCU3RI

--

Chris

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That's a totally different effect: the eye sees colours (they are a negative of the correct colours) and the eye/brain tires of seeing those colours so when a black and white image is seen, the colour sensitivity of the eye varies for different parts of the image so the eye sees a hint of the correct colours.
The one that TW demonstrated used strobing or patterning to tire some of the cones more than others in the eye, so as to achieve that same goal of varying colour sensitivity of the eye.
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On 31/12/17 11:58, Harry Bloomfield wrote:

Others have talked about the psychological experiments with B&W TV but it crosses my mind that there could be lots of reasons why a solid-state colour TV has difficulty interpreting black, white and only greyscale in between, ranging from the set, the method of transmission and even down to the transfer from celluloid to digital in the first place.
Going back even further, the original B&W film stock may not have been true black on a clear-as-water celluloid base and different chemical processes can give different results. Guess who was given a copy of "The Book of Alternative Photographic Processes (Third Edition)" for Christmas?
Nick
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Which isn't going to make any difference on a monochrome telecine. If using a colour telecine for mono film you set the greyscale to give true B&W.
--
*Never underestimate the power of stupid people in large groups.

Dave Plowman snipped-for-privacy@davenoise.co.uk London SW
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