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Are these the real Martian colors?
MERovingian
post Aug 7 2012, 03:11 PM
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We've just got the first color picture from MSL today
http://mars.jpl.nasa.gov/msl/multimedia/images/?ImageID=4282

if I understood it well, this is the first time ever that a real color camera has been sent to the Red planet.

Something is nagging me though, and certainly this is here in UMSF that I will get the correct and definitive answer.
Since the 70s and the Viking missions, there's always been debates about the real color of the surface and skies of Mars. They had indeed come up with funny results during the Viking missions with nearly blue skies!

Then came the MERs, and the pictures were, and still are (go Oppy go!), taken through three filters, and then it's all a question of mixing all this together (by now you must have guessed that I am neither a photographer nor a photoshoper!). But as often seen here on this site, everyone has then hers or his own interpretation when it comes to the final result. I have indeed seen here much better looking Martian pics than on the MER site (sometimes, not always)

All this to say that up until this morning, we weren't 100% sure that what we were seing was the real Mars, in its true colors but a very close aproximation. Correct?

So my question is this: is this picture from MSL the very first one to show us the real Martian colors??

Thanks.
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Deimos
post Aug 7 2012, 04:51 PM
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Well, it is known that Bayer filters hold the magical key to truth. And of course, beauty is truth, so better looking colors are truer. But, I think the truth is being covered up in that image (by a dusty lens cover, no less).

There is no such thing as the one "true color" for something (many illusions rely on this and consumer cameras are generally designed to correct for this). The debate will, sadly, continue. We know approximately what it looks like, and we have seen many products that have colors other than what we would perceive, but contain truth in their own ways. But if you really, truly want real, and do not accept what we measure, you must experience yourself. You cannot even rely on someone else's subjective description of what color seemed true to them--that's worse even than believing a Bayer filter pattern or a calibrated color measurement.
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RoverDriver
post Aug 7 2012, 05:02 PM
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QUOTE (Deimos @ Aug 7 2012, 09:51 AM) *
Well, it is known that Bayer filters hold the magical key to truth. And of course, beauty is truth, so better looking colors are truer. But, I think the truth is being covered up in that image (by a dusty lens cover, no less).

There is no such thing as the one "true color" for something (many illusions rely on this and consumer cameras are generally designed to correct for this). The debate will, sadly, continue. We know approximately what it looks like, and we have seen many products that have colors other than what we would perceive, but contain truth in their own ways. But if you really, truly want real, and do not accept what we measure, you must experience yourself. You cannot even rely on someone else's subjective description of what color seemed true to them--that's worse even than believing a Bayer filter pattern or a calibrated color measurement.


I could not agree more.

Paolo


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MERovingian
post Aug 7 2012, 06:18 PM
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Alas, I was born a good hundred years too early for experiencing the Martian truth all by myself! From now on, I will therefore blindly believe in the Bayer filter pattern!!

Thanks a lot Deimos for the explanation! smile.gif

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machi
post Aug 7 2012, 09:32 PM
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True colors is relative concept. I don't know about some precise definition. Every human being has slightly different perception of color and this is further affected by eye physiology, so perception is dependent even on context. Lots of visual illusions are based on that (as Deimos wrote, I agree with everything). Even every eye has different color view (you can try this easily). Another thing is brightness. Some objects are so dark, that it's nearly impossible to visualize this on computer screen.


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lyford
post Aug 7 2012, 09:35 PM
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Perceived color is such a complex interplay of elements that it almost makes no sense to ask "But what would it look like if I were standing on Mars?" Our eyes evolved to notice differences in reflected sun light in this mostly nitrogen atmosphere, even on this planet in dusk or under artificial light it is often difficult to identify and distinguish colors accurately.

I often think of underwater photography when this discussion come up. What is the "real color" of a fish? Seen in light filtered though 10 meters of sea water? Or close up in an aquarium? With a flash of white light? Through a scuba mask or bare eyed?


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elakdawalla
post Aug 7 2012, 09:42 PM
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I like that underwater analogy, it's very good to help people intuitively understand the problem with the question of color. I'm going to be using that!


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ugordan
post Aug 7 2012, 09:43 PM
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QUOTE (Deimos @ Aug 7 2012, 06:51 PM) *
Well, it is known that Bayer filters hold the magical key to truth.

That maybe tongue-in-cheek, but I'm looking forward to the one thing Bayer filters have over the classic RGB wheel approach : no more rainbow shadows, dust devils, etc. during 3 exposures. On a side note, I'm somewhat disappointed to see that apparently the lossy algorithm of choice will again be JPEG and not something wavelet-based.


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imipak
post Aug 7 2012, 09:45 PM
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See also:

Nagel, Thomas: "What Is It Like to Be a Bat?", The Philosophical Review, Vol. 83, No. 4 (Oct., 1974), pp. 435-450
(Heh, took a lot longer to find the proper reference than the text!)
[Edit: fix link, slap forehead]


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JohnVV
post Aug 7 2012, 09:48 PM
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After years of working in color photo darkrooms
I can tell you that color IS SUBJECTIVE

i can look at a print and say" it is perfect " the other owner will say "to blue "
the other silent partner might say " nice, but just a bit too warm "

so "REAL" color ??????? there is no such thing
every one sees things just a bit different
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RoverDriver
post Aug 7 2012, 11:33 PM
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QUOTE (ugordan @ Aug 7 2012, 02:43 PM) *
That maybe tongue-in-cheek, but I'm looking forward to the one thing Bayer filters have over the classic RGB wheel approach : no more rainbow shadows, dust devils, etc. during 3 exposures. On a side note, I'm somewhat disappointed to see that apparently the lossy algorithm of choice will again be JPEG and not something wavelet-based.


Are you talking for public release or for transmission to Earth?

Paolo


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Explorer1
post Aug 8 2012, 12:33 AM
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And of course, even if one was 'standing on Mars', there would still be a piece of glass or plastic between the surface and your retina. (Excepting a minute or two of essentially vacuum, or else terraformed, by which point it would be a different planet entirely).
My opinion? Look in the night sky, and you'll see the sum of every one of the planet's colors. wink.gif
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Bjorn Jonsson
post Aug 8 2012, 12:54 AM
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QUOTE (Explorer1 @ Aug 8 2012, 12:33 AM) *
My opinion? Look in the night sky, and you'll see the sum of every one of the planet's colors. wink.gif

And even that does not result in a clear answer. Due to the extreme contrast between the bright planet and the black sky the color/brightness looks different from what you would see if you were standing on the surface of Mars (just think about the Moon - it looks bright in the sky but in reality the surface is very dark, not unlike asphalt).
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Explorer1
post Aug 8 2012, 03:45 AM
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And our pictures from the lunar surface look just as white, since the only thing to contrast it with is the sky, which is just as black.
Though I wonder what effect lunar night may have; we still don't have pictures of that, AFAIK?
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dvandorn
post Aug 8 2012, 04:00 AM
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QUOTE (Explorer1 @ Aug 7 2012, 10:45 PM) *
...Though I wonder what effect lunar night may have; we still don't have pictures of that, AFAIK?


Not much from the surface, no. Though here we do have an image taken by Surveyor 1 of its own foot pad, taken at night by Earthlight. It was a 4-minute exposure, IIRC.

-the other Doug

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