Why do People Colour Nebulaes etc in Post Processing?

[RikM]

I think Michael has it right sabana. Perhaps you simply didn't understand that with RGB images the colours are already there, just really faint. In Photoshop (other processing packages are available) you adjust the brightness and contrast of the image to make the natural colours visible. This is done by adjusting the image histogram NOT by taking a paintbrush tool and 'colouring in' or painting over the image.

With narrowband images, you use filters to select only the wavelengths emitted by certain gasses. Naturally Sii is deep red, Ha is a slightly lighter red and Oiii sits right between blue and green. Many images are presented with these natural colours showing, so to present them in black and white is actually a misrepresentation. Originally for scientific interest, the image data for these gas emissions were mapped onto different colour channels to make it easier to see the structure of the chemical composition of the nebulae and try and get an understanding of how they formed. So the fact that these images are also stunningly beautiful representations of our natural universe is almost incidental.

[RobH]

[quote=sabana;2103897

The colours you say you are pulling out are most definately innacurate.

And how do you know this?

Do you have some secret way to see the 'real' colours?

If so, please post some images and enlighten us all.

[Macavity]

You (imagers) think you've got troubles? Spare a thought for the poor old VIDEO astronomy enthusiast. We're "Electronically Assisted" for starters. Then, are we "live" or "semi-live"? <G> Does a combined image, including your "computer settings", PROVE we're not cheating? I'm being unfair - And mostly <teasing>!

But the question is interesting. What constitutes reality (man)? Provided you state, approximately what you actually *DID*, to achieve your (real / unreal) masterpiece, I'm easy. By restricting folks to "approved" methods we miss out on innovation. (Camera) technology is increasingly "hybrid" now? It's quite easy to bend the rules?

Aside: People like to see attractive (inspiring) images? These days, "Scientists" seem to talk ever more about rules! <sigh> In general terms, despite their doubts, I can understand the "spirit" of things too. LOL. But restriction can discourage the sharing of information - And learning from others of a different perspective...

[Quatermass]

people will get defensive if you say there like school children colouring in there pictures but it does not change the fact that colours are subjective to our personal prefrences.

Sent from my GT-S5670 using Tapatalk

[ianaiken]

Sabana - Your post is arrogant, misinformed and insulting by the choice of words used. This is just my opinion and I stand by it too.

Edit: I've never added colour so this doesn't affect me and i respect peoples opinions when put across without causing what appears widespread offence.

[ianaiken]

And to clarify I'm referring to the analogies used and language. Debate yes but this I think is causing offense.

[msinclairinork]

Film snob maybe. Scanning done at a pro lab definately. Old school yes and no. I enjoy both forms.

But heres the thing and I'm not looking for an argument just a useful debate.

The colours you say you are pulling out are most definately innacurate. Yes its ok to enhance. But by playing with the hue and saturation in photoshop all you are doing is waht an interior designer does matching wallpaper to furniture etc etc. Not exactly a science more of an aesthetic view. Pleasing to the eye. Great, wonderful. But did you really go into astrophotography to be a Monet? If so why not just paint the picture in oils in the first place? Again the child at school analogy although strong isn't a lie. Yes its your image and you can do with it what you like. But when I look at the image (and their are plenty in this group who retain their credibility by not colouring). I look for the truth not a glorified enhancement or monstrosity.

Ok without pulling out these colours you may not see anything in the image at all. Not true. You don't have to pull out a colour. You can pull out the tone. Tone and colour BTW are two different things.

Again I'm just putting forward my opinion. Some say yes some say no. But the defensiveness of some people is just as arrogant as what my post may sound like.

It's just not so cut-and-dry. There is a lot of different factors to make you change the hue/saturation. Some of these include: quality of the camera's chip or other guts, quality of the lens/telescope, light pollution, clouds, seeing...the list goes on. But what people are mostly trying to do is to get it back to what is accepted* to the natural colours again.

*we can't know for sure what colours are 100% natural, because as mentioned before we all see things differently. But I think we can all agree that an image having colour IS natural compared to an image without it.

Question: You say you prefer using film cameras? Well I can tell you that an exposure M42 from such a camera will show up colour once printed. Would you still dispute this as being unnatural and print it in B/W instead, and then say that this is what it SHOULD look like?

Michael

[Adrian]

Edit: can't be bothered

[sabana]

I fully agree getting back to the natural colours. But its when people exploit the colour so it goes well beyond what it is supposed to be.

[Takahashi]

Examples?

[Grinde]

I fully agree getting back to the natural colours. But its when people exploit the colour so it goes well beyond what it is supposed to be.

What is it supposed to be like, then...? What's 'natural' & what's not? Are the colors 'wrong & untrue' even if a G2V calibration is done?

[foundaplanet]

I fully agree getting back to the natural colours. But its when people exploit the colour so it goes well beyond what it is supposed to be.

All due respect, there is no "what it is supposed to be".

Different rigs and different kit and different takes on different ways of processing different things give different results by different people.

Please do post some of your images it may help me get a greater understanding of what is missing...

[sabana]

God bless photoshop.

[RobH]

I fully agree getting back to the natural colours. But its when people exploit the colour so it goes well beyond what it is supposed to be.

What is natural colour....what is it 'supposed to be'?

To our eyes, virtually every nebula and galaxy up there is a faint grey smudge....is that what it's supposed to be?

To an unmodded DSLR, there is colour, but not so much deep red....is this correct?

To sensitive CCD cameras, there is lots of colour....should we not use this colour?

Imaging chips have differeing sensitivities to different wavelengths....which chip should be our benchmark?

Colour mapping when using narrowband filters gives a very different colour pallete from that which the human eye sees.....should we give up narrowband imaging, except for black and white shots?

Then we get to the issue of atmospheric refraction/light pollution etc....how do we deal with this....do we leave the colour balance as it is or do we attempt to correct for these effects?

Do you know about G2V star calibration? Many of us use this method to obtain a colour balance that uses a sun like star as the reference for white.

There are as many different approaches to colour in terms of intensity and saturation as there are people taking astro photos....I prefer some above others but this is purely my taste and does not put me in a position of saying that if something isn't to my taste then it is wrong, nor would I have such a high opinion of myself to do such a thing.

One thing is sure....in the RGB images you see, the colour is most definately there....how individuals choose to show this colour is entirely up to them.

You appear to have a monopoly on knowing what the 'correct' colours are.....I ask you again, please post some of your own images so we can see what you think is 'natural'.

Rob

[Rob L]

God bless photoshop.

Photoshop is just a tool, like the camera, telescope and mount.

[dark knight]

Sabana, when we look to the skies at night our eyes are not designed to pick out the colours up there, this does not mean those colours do not exist, merely we can't detect them. A digital dslr does not have the same problem as our eyes and the "chip" is designed to photograph what is actually there, the camera gives the real picture, without the camera you would just see blacks and greys, you are in effect being cheated of the truth by your own eyes. We live in a world where technology is playing an ever increasing role and I for one have no problem embracing it. There are elements I don't like but the idea of posting comments or opening up a debate is to be constructive, not to slag people off by making cheap comments that are not needed by the debate, I refer to the children colouring analogy, this serves no purpose in a debate at all. I may not like the Hubble Pallet but I sure as hell respect the time, skill and effort of the imager, remember the image had to be captured in the first place. You don't have to like everything and you can voice that opinion, but do it with at least some respect for the people your criticising.

[Takahashi]

God bless photoshop.

OK, now you're just trolling.

[saturn5]

God bless photoshop.

If people wish to enhance their photos because the technology is there to do so then that is their choice and to do with the colours whatever they wish.

How you know what the correct colours are meant to be is quite beyong me.

If you do not wish to embrace the technology or be creative,prefering your photo colours "as is" then so be it but dont have a go at others who do just because you prefer realism.

If everyone did their photos "as is" photography would be one of the most boring and unimaginative hobbies possible.

I detest photography snobbery and it always comes from the realism camp who think their way is the only way.

God bless the colour police..NOT!!

[Ags]

This thread is wierd.

I gues looking through a scope at the stars is not the truth either. The only true form of astronomy,without any intervening 'false' optical or digital enhancements, would be looking up with the naked eye. The solar observers would have a problem... :-) and as for solar images - why do they make their images so dim? The pics should burn a hole in my monitor. Fake, man!

[valleyman]

You said what I wanted to say Dark Knight, but much more elegantly.

Some of the comments on this thread are completly with out foundation.

[Quatermass]

Saying God Bless photoshop shows that you really have a bee in your bonnet with this colour issue but you cant stop people doing what they like with there own images so why let it bother you so much. I see lots of images on here where the colours are greatly varied its not a lie its just people using colours that they like. A recent one of m33 was a lovely blue who can say what it really looks like? But I suspect that would really bug you.

Sent from my GT-S5670 using Tapatalk

[swamp thing]

A recent one of m33 was a lovely blue who can say what it really looks like?

It's grey. I've seen it.

[gdheib0430]

Yeah red no need to be scared to post pictures on here. I have put up some very sub par noob shots and didn't get a single laugh...everyone starts somewhere and hopefully what I have learned from what people commented on mine will help me improved the next go around.

As for post processing in PS...99.9% of the people on here will up the contrast, adjust levels, or up the saturation a tiny bit to get rid of light pollution and pull more of the data out of the image...they in no way actually choose a color and paint it on the image that would be crazy and they would probably get laughed off the site or told not to do that unless it is in the art and scetch section where you can go crazy (or see some incredible scetches). As for seeing different colors in the pictures it really depends on your elevation, LP, filters, exposure time and chip you are using to capture an image or sets of images.

[sanmatt]

There doesn't need to be two camps - one artistic and one scientific. The 2 can be combined. As mentioned before about staining tissue sections to look at under the microcope. I do this all day every day being a histologist, yes we use a combination of tinctatorial stains and impregnantions to highlight certain elements of the cells structure and also to find (if actually there) other things such as bacterium - for diagnostic purposes.

But hell they sure do look pretty. And why not? I firmly believe that stained histology sections are very artistic - ever looked at a cross section of the ureter with H&E stainin? Pretty as anything.

Ever see the kidney's glomerili stained in H&E? Again very pretty.

Alcian blue for acid mucins - gorgeous.

[Ags]

It's grey. I've seen it.

Most people who see color in M42 claim green or blue tinges, perhaps a little pink. But imagers often produce a strongly red rendition. Obviously the chip is more sensitive to those wavelengths than the eye is, but that does not make the images 'wrong' in any sense - astronomy is all about using equipment to enhance the weak (and often entirely non-visual) signal from very distant objects. Without equipment and enhancement, astronomy could hardly exist.