StarTools

Hello,

I like ST a lot. Each version has improved compared with the previous one, but the change from the old Color Module (with just one saturation slider) to the new one (with 3 of them) has left me a bit bothered. The previous one was very intuitive, but in this one I just cannot get the colors right. Is there a way I can revert to the old version? Or at least can you walk me through the new process, compared with the previous one? I understand what the new sliders mean, but I cannot get the two work the way I want.

In the meantime, where can I get the ST version prior to the Color Module Change? I think it was 1.3.1.212.

Thanks!
Gustavo

gustavo_sanchez wrote:Hello,
I like ST a lot. Each version has improved compared with the previous one, but the change from the old Color Module (with just one saturation slider) to the new one (with 3 of them) has left me a bit bothered. The previous one was very intuitive, but in this one I just cannot get the colors right. Is there a way I can revert to the old version? Or at least can you walk me through the new process, compared with the previous one? I understand what the new sliders mean, but I cannot get the two work the way I want.

No problem Gustavo (and sorry you're having trouble).
The new Color module (which should *really* yield much superior results to the old one) is best used right before switching tracking off.
Assuming you have removed any colored gradients or light pollution using the WIpe module, it is now simply a matter of finding the correct color balance. This is now a pretty simple affair;

• If the image is too red, increase the green and blue multipliers.
• If the image is too green, increase the red and blue multipliers.
• If the image is too blue, increase the red and green multipliers.
• Use the starfield as a reference - you should see a nice continuum from red, orange to yellow white and blue stars, equally distributed.
• Increase top end saturation response to bring color into the brighter regions (often a value of 9.90 works just fine)
• Increase bottom end saturation just before the background starts to become colored. You'll want to keep the background nice and neutral (black/greyish).

StarTools now uses the color information as it was when it was linear (e.g. unstretched), although still calibrated by the Wipe module. This means that any stretching you have performed on a pixel does not impact the color of that pixel. For example, this allows you to show the Orion nebula's core in its true colors (which are not markedly different from its surroundings), instead of seeing it as a bright colorless affair - StarTools decouples how you treated your luminance information from your color information.
The old way made the user to approximate the stretching using a sub-optimal gamma adjust which never really got the color right.
If you still have trouble attaining correct color, do share your dataset with me, so I can do a personalized tutorial or fix the Color module if indeed it turns out to be inadequate for your purpose!

In the meantime, where can I get the ST version prior to the Color Module Change? I think it was 1.3.1.212.

That's correct! (according to the change log).
You can still find the old version here.

Gustavo,

I had troubles as well early on..and still do at times. While I have noticed that the new module makes it possible to have much better control, and really "nail" the balance you're after, it isn't quite as intuitive...to me anyway...as the old one was. Classic issue in system development...the more powerful a tool is, the more difficult it can be to use.

For what it's worth, however, I HAVE found what seems to be a fairly reliable "starting point"...for me anyway.

I start by bumping the saturation up very high. 400-500% or more is not uncommon. Slider in the middle of the range or so.

Next, I'll increase the Red level to 1.10 or so.

From here, I start with top and bottom end adjustments.

I move the top end slider until the "average" star in the field...in other words, the "majority" stars...are heavily over-saturated and "blown out". In other words, they look like neon red "blotches" of color, not stars.

I then do the same with the bottom end slider, looking this time at the "fringes" of DSOs, or perhaps the fainter background galaxies...the faint fuzzy stuff. I'm looking for it to take on an over-exposed "blown out" look as well.

From here I pull the saturation down to about half of where it was, and pull the top and bottom end sliders back about 10% or so.

These are usually pretty close to where my final result winds up. What I've found is that doing the Top and Bottom end that way lets me know just about where the "max" is that I can get away with, without oversaturating things. Once I know that setting, I can start tweaking colors and saturation to see the effect...and the change will happen fairly quickly and noticeably at those levels.

I know it's sort of a vague "feel as you go" method...but it's worked for me, and I've been finding some color balances lately that I, at least, am reasonably happy with.

Thanks for chiming in on this issue Gordon - It's good to know it works reliably for you, but I may have to have a look at making the procedure more intuitive...

gboulton wrote:Gustavo,

I had troubles as well early on..and still do at times. While I have noticed that the new module makes it possible to have much better control, and really "nail" the balance you're after, it isn't quite as intuitive...to me anyway...as the old one was. Classic issue in system development...the more powerful a tool is, the more difficult it can be to use.

For what it's worth, however, I HAVE found what seems to be a fairly reliable "starting point"...for me anyway.

I start by bumping the saturation up very high. 400-500% or more is not uncommon. Slider in the middle of the range or so.

Next, I'll increase the Red level to 1.10 or so.

From here, I start with top and bottom end adjustments.

I move the top end slider until the "average" star in the field...in other words, the "majority" stars...are heavily over-saturated and "blown out". In other words, they look like neon red "blotches" of color, not stars.

I then do the same with the bottom end slider, looking this time at the "fringes" of DSOs, or perhaps the fainter background galaxies...the faint fuzzy stuff. I'm looking for it to take on an over-exposed "blown out" look as well.

From here I pull the saturation down to about half of where it was, and pull the top and bottom end sliders back about 10% or so.

These are usually pretty close to where my final result winds up. What I've found is that doing the Top and Bottom end that way lets me know just about where the "max" is that I can get away with, without oversaturating things. Once I know that setting, I can start tweaking colors and saturation to see the effect...and the change will happen fairly quickly and noticeably at those levels.

I know it's sort of a vague "feel as you go" method...but it's worked for me, and I've been finding some color balances lately that I, at least, am reasonably happy with.

admin wrote:Thanks for chiming in on this issue Gordon - It's good to know it works reliably for you, but I may have to have a look at making the procedure more intuitive...

Could there be a way to maybe...drop one slider?

Maybe "Top End Saturation" and "Bottom End Saturation"?

I have no idea...I'm just sort of head-scratching here.

I will say this, however...over on the other side, with the Red/Blue?green balance, I have long felt that that could be simplified a bit..or at least more intuitive for ME...if the defaults were somewhere in the middle of the slider range,a nd i could DECREASE a color. Especially when i'm shooting my IR-modded camera, and get all those nasty reds from LP...being able to pull red back, instead of figuring out how much to bump the other two would, i think, seem simpler to me.

But...again...just head-scratching.

gboulton wrote:

admin wrote:Thanks for chiming in on this issue Gordon - It's good to know it works reliably for you, but I may have to have a look at making the procedure more intuitive...

Could there be a way to maybe...drop one slider?

Maybe "Top End Saturation" and "Bottom End Saturation"?

I have no idea...I'm just sort of head-scratching here.

I'm afraid these are quite essential. It's this or bothering the user with saturation response curves...

I will say this, however...over on the other side, with the Red/Blue?green balance, I have long felt that that could be simplified a bit..or at least more intuitive for ME...if the defaults were somewhere in the middle of the slider range,a nd i could DECREASE a color. Especially when i'm shooting my IR-modded camera, and get all those nasty reds from LP...being able to pull red back, instead of figuring out how much to bump the other two would, i think, seem simpler to me.
But...again...just head-scratching.

Yep, good observation and exactly what I was thinking of fixing.

admin wrote:I'm afraid these are quite essential. It's this or bothering the user with saturation response curves...

Fair enough...I'll just nod my head and pretend to understand that.

Yep, good observation and exactly what I was thinking of fixing.

Yay! I contributed!

admin wrote:

gustavo_sanchez wrote:Hello,
I like ST a lot. Each version has improved compared with the previous one, but the change from the old Color Module (with just one saturation slider) to the new one (with 3 of them) has left me a bit bothered. The previous one was very intuitive, but in this one I just cannot get the colors right. Is there a way I can revert to the old version? Or at least can you walk me through the new process, compared with the previous one? I understand what the new sliders mean, but I cannot get the two work the way I want.

No problem Gustavo (and sorry you're having trouble).
The new Color module (which should *really* yield much superior results to the old one) is best used right before switching tracking off.
Assuming you have removed any colored gradients or light pollution using the WIpe module, it is now simply a matter of finding the correct color balance. This is now a pretty simple affair;

• If the image is too red, increase the green and blue multipliers.
• If the image is too green, increase the red and blue multipliers.
• If the image is too blue, increase the red and green multipliers.
• Use the starfield as a reference - you should see a nice continuum from red, orange to yellow white and blue stars, equally distributed.
• Increase top end saturation response to bring color into the brighter regions (often a value of 9.90 works just fine)
• Increase bottom end saturation just before the background starts to become colored. You'll want to keep the background nice and neutral (black/greyish).

StarTools now uses the color information as it was when it was linear (e.g. unstretched), although still calibrated by the Wipe module. This means that any stretching you have performed on a pixel does not impact the color of that pixel. For example, this allows you to show the Orion nebula's core in its true colors (which are not markedly different from its surroundings), instead of seeing it as a bright colorless affair - StarTools decouples how you treated your luminance information from your color information.
The old way made the user to approximate the stretching using a sub-optimal gamma adjust which never really got the color right.
If you still have trouble attaining correct color, do share your dataset with me, so I can do a personalized tutorial or fix the Color module if indeed it turns out to be inadequate for your purpose!

In the meantime, where can I get the ST version prior to the Color Module Change? I think it was 1.3.1.212.

That's correct! (according to the change log).
You can still find the old version here.

It would be an honor for me if you could help me out with one of my own images, if at least to better understand how to use the Color Module. This is a stack of 21 5-minute images of Messier 64: http://db.tt/O6IZW48M

If you need the raw images, they are here: http://db.tt/kJXDaOCL

I will try applying the suggestions you made, and also will try with the old Color Module version.

Thanks a lot!

gboulton wrote:

admin wrote:I'm afraid these are quite essential. It's this or bothering the user with saturation response curves...

Fair enough...I'll just nod my head and pretend to understand that.

Exactly my point - I'd rather have just two parameters that you need to get your head around, than to have something even less comprehensible (which would do the same job).

Yay! I contributed!

You've had your hand in a good few features/improvements now Gordon. Many thanks to you (and now Gustavo) for the occasional kick up the backside!

gustavo_sanchez wrote: It would be an honor for me if you could help me out with one of my own images, if at least to better understand how to use the Color Module. This is a stack of 21 5-minute images of Messier 64: http://db.tt/O6IZW48M

Awesome! This really helps.
I'll see if I can get a good color balance with the Color module as is. I will also be updating the Color module with Gordon's suggestion. Stay tuned!