Author Topic: Blue glow  (Read 49816 times)

Offline Echnaton

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Re: Blue glow
« Reply #30 on: June 26, 2012, 06:49:09 PM »
The Physicist: It is completely full, half with liquid, the other half with air.
The Homemaker: It doesn't matter, I have to wash it later either way.
The Drunk: Somebody left the ice out of my drink.
The sun shone, having no alternative, on the nothing new. —Samuel Beckett

Offline chrisbobson

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Re: Blue glow
« Reply #31 on: January 09, 2013, 06:28:45 AM »
Question, in many of the images in AS12-46 there is a blue glow around brightly lit objects (for example : AS12-46-6826).
It looks like a result of the over-exposed object but why is it a halo-like blue glow?

Could also be a blue screen halo effect perhaps.

Offline Sus_pilot

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Blue glow
« Reply #32 on: January 09, 2013, 06:39:00 AM »
Question, in many of the images in AS12-46 there is a blue glow around brightly lit objects (for example : AS12-46-6826).
It looks like a result of the over-exposed object but why is it a halo-like blue glow?

Could also be a blue screen halo effect perhaps.

Halation. When I was in high school, after seeing Nicholas and Alexandra, I deliberately shot a lot of Ektachrome (and burned a lot of mom and dad's money) trying for (and getting) the same affect.

I haven't tried it with a digital camera yet, but I suspect, given how hard the engineering types have worked to emulate film, that I'd get the same thing...

Offline chrisbobson

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Re: Blue glow
« Reply #33 on: January 09, 2013, 06:43:09 AM »
I have a big 500mm Sigma lens, get some blue glow with that at times.

Offline Sus_pilot

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Blue glow
« Reply #34 on: January 09, 2013, 06:58:29 AM »
In this case, I'm referring to an artifact due to the film's emulsion, not the optics. 

Offline chrisbobson

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Re: Blue glow
« Reply #35 on: January 09, 2013, 07:00:13 AM »
Also with green chromakey you can get a bluish glow.

Offline Sus_pilot

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Blue glow
« Reply #36 on: January 09, 2013, 07:10:27 AM »
Also with green chromakey you can get a bluish glow.
Doesn't look the same.   One is due to diffraction within the film emulsion and some reflection off the film itself due to sever over-exposure.  The other is caused by bleed through in the electronics. 

I'll let dwight and Jay deal with the latter, though - I'm better at photography than videography.

Offline chrisbobson

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Re: Blue glow
« Reply #37 on: January 09, 2013, 07:11:37 AM »
Given my experience with my Sigma lens, I would guess lens effect is number one on the list of explanations.

Offline dwight

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Re: Blue glow
« Reply #38 on: January 09, 2013, 09:06:50 AM »
Chroma key, you say? It is pretty blatantly obvious you wouldn't know a chroma key from a bucket of black level amidst a bunch of color bars.
"Honeysuckle TV on line!"

Offline ka9q

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Re: Blue glow
« Reply #39 on: January 09, 2013, 09:14:40 AM »
Or a bucket of blacker-than-black...

Offline dwight

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Re: Blue glow
« Reply #40 on: January 09, 2013, 09:15:29 AM »
Mind you, I'm pretty sure a chroma-key goes hand in hand with a gen-lock.
"Honeysuckle TV on line!"

Offline ka9q

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Re: Blue glow
« Reply #41 on: January 09, 2013, 09:18:24 AM »
And when you open it, it leads you right to the back porch, where you may or may not find a burst of color.

Offline dwight

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Re: Blue glow
« Reply #42 on: January 09, 2013, 09:21:34 AM »
Never the same color?
"Honeysuckle TV on line!"

Offline ineluki

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Re: Blue glow
« Reply #43 on: January 09, 2013, 09:27:31 AM »
Those two were useless.  First, they destroy the television camera.  Then they smudge the camera lens on one of the Hasselblads.  Then they leave a magazine on the surface.

I think all the astronauts should be fined for littering...

Offline ka9q

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Re: Blue glow
« Reply #44 on: January 09, 2013, 10:10:06 AM »
Never the same color?
Never TWICE the same color. NTSC.

At least that's how I heard it when I was in TV broadcasting. (It kinda earned its name, too.)

I also learned that SECAM stood for Something Essentially Contrary to the American Method (after all, it was French), and PAL was Peace At Last.