saturated mcsaturated face

[TiffsAndAstro]

so two images for your perusal here, both starless. 'default' image and a completely UNsaturated version. why does the desaturated version looks "better" to my eyes? simple as just too much saturation? probably from human weighted GHS? ill obviously jinx it, but the unsaturated almost mono version is bordering on decent looking? jpg lessons the effect a little i think, but even so....

 

 

Edited July 29 by TiffsAndAstro

[vlaiv]

I think it has to do with amount of local contrast you are able to see due to how color and screens work.

Saturated red color maxes out at about half of total brightness range. Which means that you have about half of "steps" to record local contrast if you use red color.

Look at this part of the image:

feature looks "flat" not much variation in brightness between feature and background - but look at this from "mono" image:

Much more shades visible and it looks like local contrast is improved - it looks like you see more detail because of this - or at least see it more clearly.

You can also go the other way around:

Take nice monochrome image:

and assign it to red channel only

it will instantly look flatter and with less detail than original for the same reason.

[TiffsAndAstro]

Just now, vlaiv said:

I think it has to do with amount of local contrast you are able to see due to how color and screens work.

Saturated red color maxes out at about half of total brightness range. Which means that you have about half of "steps" to record local contrast if you use red color.

Look at this part of the image:

feature looks "flat" not much variation in brightness between feature and background - but look at this from "mono" image:

Much more shades visible and it looks like local contrast is improved - it looks like you see more detail because of this - or at least see it more clearly.

You can also go the other way around:

Take nice monochrome image:

and assign it to red channel only

it will instantly look flatter and with less detail than original for the same reason.

wow that's another amazing explanation, ty again.

is there a technique for working with this, or is it "adjust to taste"?

this is what i've managed so far, but tricky in daylight. will do a "proper, full" post process once its darker

 

[vlaiv]

Just now, TiffsAndAstro said:

is there a technique for working with this, or is it "adjust to taste"?

It really depends on what you are trying to achieve.

With images like this one - we are mostly capturing Ha signal - which is monochromatic light at ~656nm. That is deep dark red color. It is even darker than red above that we used in examples. If you own Ha filter - you can see for your self what it looks like - just hold the filter against the eye and look thru it.

That color is very hard to reproduce. It can be done, but it is hard. For this reason we turn to full red channel often.

Bottom line - if you really want to recreate sort of look that would be seen by human eye under certain conditions - it can be done, one just needs to pay attention to a lot of technical details (proper color management and possibly capturing Ha signal on its own to throw into the mix as OSC sensors are not very good at capturing it the way we see it), otherwise - go by the feel. It would help if you actually look at Ha light with your eyes - thru the filter so you know what sort of "red" effect you want to achieve.

Same thing goes for OIII - it is also very specific color when viewed with our eyes.

On the other hand - stars are much more easy to process to exact color. Their color primarily depends on their temperature and falls on this scale:

or this continuum:

(mind you - above continuum goes only to 12000K while star temperature can go way above that to more than 30000K)

[TiffsAndAstro]

3 minutes ago, vlaiv said:

It really depends on what you are trying to achieve.

With images like this one - we are mostly capturing Ha signal - which is monochromatic light at ~656nm. That is deep dark red color. It is even darker than red above that we used in examples. If you own Ha filter - you can see for your self what it looks like - just hold the filter against the eye and look thru it.

That color is very hard to reproduce. It can be done, but it is hard. For this reason we turn to full red channel often.

Bottom line - if you really want to recreate sort of look that would be seen by human eye under certain conditions - it can be done, one just needs to pay attention to a lot of technical details (proper color management and possibly capturing Ha signal on its own to throw into the mix as OSC sensors are not very good at capturing it the way we see it), otherwise - go by the feel. It would help if you actually look at Ha light with your eyes - thru the filter so you know what sort of "red" effect you want to achieve.

Same thing goes for OIII - it is also very specific color when viewed with our eyes.

On the other hand - stars are much more easy to process to exact color. Their color primarily depends on their temperature and falls on this scale:

or this continuum:

(mind you - above continuum goes only to 12000K while star temperature can go way above that to more than 30000K)

Ha Oiii filter is on my list.

I might have a try at extracting Ha from my data as if I was using a ha Oiii filter and comp it back in as luminous channel just for lulz. 

Also ngc6888 seems viewable for a month or two yet so I'll probably try some more milk way core ish targets.

I was impressed with my 12 entire minutes on omega nebula.

Ty again.

Edited July 29 by TiffsAndAstro