They're just methods and each will yield different results.
The problem, as I see it, is not in what method is being used but in believing that using this or that method will give us a more accurate, or neutral image.
To me, these are just different interpretations and presentations. Each one has a place. And I don't think neither has better or worst documentary value, using the word documentary the way I think you understand it.
If Pepito took an image and used the G2V method, great, we know how the colors look using that method.
If Juanito used the "structure detection" method, great, we know how they look using that method.
Neither is showing me the REAL color anyway, right?
Your last image definitely gives a much more anthropocentric view of this famous trio, Vicent >:D >:D >:D
"anthropocentric" images. And I'm not defending the tool, just stating a fact.
Posting one with the colors so terribly balanced as you just did (from this very anthropocentric human perspective) might diminish your credibility rather than the "accuracy" (or lack thereof) of eXcalibrator.
Be careful.
Your last image definitely gives a much more anthropocentric view of this famous trio, Vicent >:D >:D >:D
"anthropocentric" images. And I'm not defending the tool, just stating a fact.
Posting one with the colors so terribly balanced as you just did (from this very anthropocentric human perspective) might diminish your credibility rather than the "accuracy" (or lack thereof) of eXcalibrator.
Be careful.
I did not think Vicent Excalibrator image was balanced that much differently. It still has redder tone.
Certainly, Antonio's image looks better but is fully processed.
Max
On the other hand, in the CC image, I see green stars. And that too bothers me.
You will have always green stars, unless you have a huge color cast in your image.
You will have always green stars, unless you have a huge color cast in your image.
Why do I never see them in any image?
I think it is quite natural for most images to use a color balance that results in white impression for objects that most people would expect to be white. And this usually is the "average" star, some star cluster or galaxy. G2V also does have merits, but it is certainly not the aspect of "true" perceived color.
Because there are techniques to limit green values. SCNR is one of them.You will have always green stars, unless you have a huge color cast in your image.Why do I never see them in any image?
But, thru the years, a key point of G2V calibration has become to represent star colors as we would see them. This is not tru, IMHO.
See here for examples:
http://www.newworldencyclopedia.org/entry/Image:PlanckianLocus.png
http://www.midnightkite.com/color.html
Looking at the examples it appears the is a some blue green fringes around many of the stars. This is more prominent with the PI methoid in this image. I think this increases the green star preception.
What do you think?
In general, I don't see green stars in my images using the PI methoid.
Generally, I am using stars-structure rather than a galaxy.
Max
if our image shows green stars, why do we "change" them in our image to something else?
Looking at the examples it appears the is a some blue green fringes around many of the stars. This is more prominent with the PI methoid in this image. I think this increases the green star preception.
What do you think?
In general, I don't see green stars in my images using the PI methoid.
Generally, I am using stars-structure rather than a galaxy.
Max
Hi Max,
in my experience, star colors vary largely with filter transmission / sensor QE curves. For example, I remember that, when I worked with DSLR, I always had pink stars. :)
Honestly, I don't know which filter set Oriol and Ivette used for this image.
V.
Quoteif our image shows green stars, why do we "change" them in our image to something else?
Ideally, if we acquire RGB images with a filter set well correlated with human vision, then there should be no green stars. For example, it is very difficult (impossible?) to get any green stars with a DSLR camera. If our filters don't have good crossovers and/or their transmittance peaks don't correspond well to the sensitivity peaks of human vision for each color, then we can consider green stars as an instrumental defect —on the basis that our initial goal is reproducing red, green and blue as we perceive them under normal conditions— and try to fix them. This is how I see this problem, at least; others may have different interpretations.
but the principle being discussed is precisely that our vision system shouldn't be used as a reference, shouldn't those who try to avoid "the human bias" then leave the "green" stars alone?
Why not, if for a given image that remapping achieves a better visual separation of structures, or any other improvement that could be desirable for documentary or communication purposes? Or just because the author thinks the image has more aesthetic value in that way. As long as coherent and well-founded criteria are used, we have no problems with that things.
Credibility can be diminished not when someone cheats, but when they don't provide enough proof (burden of proof).
And that is what Vicent did this time with his first post, just three jpegs and "have a go at it"... which is the post that caused me to warn him to be careful.
The talk-behind-the-back in this discipline (and so many others) sometimes is quite bad, unfortunately.
Hi Edif,And our visual system can change its calibration very rapidly. Move to a planet orbiting a red dwarf and it will look white within a day. Another example I like is the experience of looking at a computer shielded by a red screen while photographing. The screen looks quite normal once you have been looking at it for a while. Glance quickly at Jupiter after looking at the screen and Jupiter is a nice green colour.
actually, the sun is a star that emits most of its energy in green light. Only our visual system is calibrated to see it as white .
What do you think about the methode used in Theli, the images are registered on a star catalog and a colorcalibration is also used on it.