19 replies to this topic

[rj144]

I usually process my pics with a fairly dark background because I hate noise.  Most comment on this and when I have a final image now, I intentionally try to do a lighter background for this reason.

 

But why, by consensus, is this preferred even if there is noise in the image?  I understand that most want faint details to be shown, but if it's at the expense of more noise, I, personally, would much rather clip those details to get rid of noise.  For me, noise is distracting and if it's easily seen, it's what I stare at, not the subject of the photo.

 

Just curious.

[Older Padawan]

I'm sure it's just personal choice and nothing more but your post is food for thought

[jonnybravo0311]

You kind of answered your own question. People put up with noise to see the faintest details. People also spend a whole heap of time to get as much total integration time as possible and use a slew of different processing techniques to mitigate the noise while still retaining the faint details.

 

To be perfectly blunt, people will look at your approach as laziness. Rather than take the time to gather more data, or take the time to really work on the data you do have, you just clip out the blacks and lose faint details.

[rj144]

You kind of answered your own question. People put up with noise to see the faintest details. People also spend a whole heap of time to get as much total integration time as possible and use a slew of different processing techniques to mitigate the noise while still retaining the faint details.

 

To be perfectly blunt, people will look at your approach as laziness. Rather than take the time to gather more data, or take the time to really work on the data you do have, you just clip out the blacks and lose faint details.

Thanks.  Yes, that's true.

[JamesTX]

There is a lot of reasons, but in the end its up to personal taste.  For example, with SHO/Hubble Palette images the current trend is to completely remove the green but I prefer to keep a little in the images.

 

In regards to the background some of the reasons:

 

• The natural background of the night sky isn't pitch black
• Too much contrast
• Some people actually like a nice even grain of noise.  Again, personal taste.. but high quality data, without bad gradients.. the noise grain can actually be a bit pleasing.

 

Of coarse, going too light is great either.  I'm guilty of this.  Too light hurts contrast and as you noted, exposes all the noise and other problems.  I try to find the right balance.  The better your data is, the easier it is to get by without having the cover the imperfections

[Madratter]

Because by clipping blacks, you permanently lose information about what you are imaging. And it causes artifacts, such as hard edges where there should be soft edges, etc. Basically, you are hiding your images faults both from others and more importantly, yourself. If you don't hide those faults, you are more likely to take the actions necessary to cure them.

[Jim Waters]

First of all I Dither and do noise reduction.  Darker backgrounds clip valuable signal / data and eliminate faint details.

[wrnchhead]

Yeah, it's just opinions. Artistic license. I am in your camp, I prefer a darker background, even when I have 50 hours on a target. 

[ChiTownXring]

I am new to the hobby but from what I have seen and read it's all part of a progression in the hobby.. The quality of my first images didn't really matter I was just amazed at being able to take pictures of M42 and show some detail and nebulosity. But after seeing hundreds of images and reading the critiques I now look at images in whole and marvel at them but then I look for the imperfections so I can then read the equipment used and integration time and take note if I would buy said equipment. I now can almost always tell if someone has clipped out faint details to hide noise. I also feel that depending on what the subject matter is clipping detail to hide noise sometimes works for me. Like others have said it's all about what makes you feel good in the end.

[imtl]

Yeah, it's just opinions. Artistic license. I am in your camp, I prefer a darker background, even when I have 50 hours on a target. 

clipping faint details in not a matter of opinion. It's a fact. Whether you care about it or not is an opinion.

BTW, the skies are not black by nature. So, it's really a personal preference/artistic/hiding noise to make them black.

[rj144]

I understand this will get a lot of flack as it's a whole different beast because the S/N is insane... but Hubble's backgrounds are very black to me:

 

Edited by rj144, 23 January 2021 - 04:28 PM.

[imtl]

Hubble does SHO and from space. We're discussing sky background from earth.

[Mike in Rancho]

I'll take the darker background any day of the week.    They just look better, and yes obviously that's personal opinion.

 

I agree some images are crushed too black to deal with defects, and which looks a bit off overall especially when it doesn't blend to the object well.  Though that can create an interesting 3D effect.

 

I don't subscribe to gray being natural.  None of this - long integration, stretching, and all the other stuff we do - is terribly natural.  And after doing all that work, why in the world would we be trying to preserve skyglow that we were battling through to see the target?

 

I've recently been practicing with the Elf data, and often like to give it a lighter stretch because that's the way I want to show it, even though his data can clearly take a stronger stretch and reveal more dust across the starfield if you want to show that also.

 

Most famous AP image of all time is probably Earthrise, and that's a pretty deep black field.

[wrnchhead]

clipping faint details in not a matter of opinion. It's a fact. Whether you care about it or not is an opinion.

BTW, the skies are not black by nature. So, it's really a personal preference/artistic/hiding noise to make them black.

I wasn't saying the clipping of faint details was a subject of opinion, I meant the appeal of the result. 

 

It's about your target audience I suppose. I have never shown one of my photos to anyone in person who said "you clipped the faint details to reduce the noise"

[Madratter]

Frankly, if you like deeper blacks, there are better ways to achieve it than clipping the blacks. For example, you can use an S contrast curve with a curves transformation tool in whatever post-processing program you are using. That gets deeper blacks without creating some of the artifacts that go with clipping.

 

Anyway, from my point of view, this forum is about learning and teaching astrophotography, and clipping blacks doesn't further that aim, regardless of how you might feel about it aesthetically.

[copper280z]

I understand this will get a lot of flack as it's a whole different beast because the S/N is insane... but Hubble's backgrounds are very black to me:

 

That was a processing choice made by the person processing it, the real data does NOT have the background clipped to zero. I suggest downloading some hubble data and processing it yourself, it's very interesting to see what basically perfect data is like to work with. Here is hubble M51 data that I processed. In the full resolution image, in the backround, you can pick out countless little galaxies and other faint fuzzies.

 

[Stelios]

Darkening to hide noise is like wearing a muscle suit to show your body building progress.

 

It's not that there's anything wrong with muscles. It's the fakeness of the suit that's "wrong." And it's exactly the same with dark background. If you can get it the correct way--by preserving the detail in your image and reducing noise through longer integrations, dithering, and denoising routines, then it's great. If you do it by raising the black point to indiscriminately block out noise, then that's the "muscle suit," and leaves the exact same impression on experienced viewers. 

[SteveL42]

Know your audience.  If you're audience is astrophotographers on Cloudy Nights, well, they have weighed in.  If the audience is you - do what makes you happy.  I have spent probably 40 years being an amateur photographer (a little pro work about 20 years ago), wound my own cans, had a darkroom, learned all about composition, lighting, developing, printing, etc.  I started out doing the "correct" things, and that was an OK formula to get started with.

 

However, creativity and originality don't necessarily follow rules.  

 

Understanding how/why things work is important, that allows you to understand the tradeoffs, how how to approach something.  I am still a beginner to astrophotography, but the some things are the same as any other photographic or artistic endeavor.  Know your audience.  If the audience is you, and your inner critic is happy, you have done well. Enjoy what makes you happy!

[pptw]

very interesting discussion, and I think it's fairly related to the science/art disucussion. it all comes down to personal preferences. the experts here will probably do everything within their or their hardwares capabilities to get a very low-noise and realistic result without clipping anything, while other's shorter in the hobby might care more about the visual result rather than the correct/real way of getting it.

 

me myself, I just started with astrophotography, and I don't mind having a dark background with a liiiitle big of clipping maybe if it leads to a 'nicer'  result, with less noise. is it cheating? don't know? is it the wrong way? don't know. do I like the result? yes. so I fully agree with Steve, know your audience, and do it the way you like it.

 

i tend to have a darker image (preferably without clipping of course) where noise is less present, than a brighter image where more faint signal is visible, but also more noise. it's a hobby in the end and the time, money and energy you put into it needs to be proportional to the joy and fun  you get out of it.

 

me being family man with young kids and busy job; i would never enjoy shooting the same target in mono with different filters, power boxes, a few wlks of heavy equipment, laptops, wires, etc. because that time spend on getting a better image is just not worth it for me. I rather shoot with lightweight mount, dslr, shorter exposure, and have dark bg with maybe some clipping but a satisfactionary result for myself, achieved over 1 short evening, when I do have that opportunity and energy to go out for a few hours. it's all about yourself in the end

[WadeH237]

When I process an image, I let the data determine how dark the background will be.  Specifically, I avoid clipping the background.  The "real" sky has noise.  It's just the nature of how how light arrives at the sensor - or even your eye.

 

Here is a simple experiment that you can do with a regular photograph of the daytime sky:

 

Zoom in on any photograph that has a daytime, blue sky until you can see individual pixels.  Notice that they are not all the same color blue.  That is noise.  Specifically, it's what we call "shot noise", which is inherent to the signal itself and has nothing to do with the equipment that is taking the image (even if you look at the sky with your naked eyes, this noise is present).  Now, take your image editing software and reduce the contrast in the sky until the pixels are all the exact same color of blue and zoom back out.  You will notice that the sky looks "wrong".  It will have a cartoonish, plastic appearance without that shot noise.

 

I've made a couple of images from dark sky sites, with lots of exposure time, where the background noise is very low.  When I've set the black point on them, the background gets very dark while still not clipping any pixels.  I've gotten so used to seeing the background, that those images look a bit unnatural to me, even though they are not clipped.

 

Of course, whether you like the effect is a matter of personal taste, but the above is the reason that many of us don't push the background sky to very black.