Yes I did have a go at your data and to be honest, my experience with adjusting color is still a bit limited in APP as my routine has always been to do that in PI. ;) But, I had the exact same result as Mike, couldn't get the saturation up to my liking and with a bit of a green cast after calibration. Indeed, without using that it looks a bit more like what you would expect. The routine is constantly being addressed and improved as can be seen in the latest 1.069. Could you check if that gives a slightly better result?

I cannot say that I am expert in APP but my understanding of what Mabula has said in his video tutorials and Forum posts is the Magenta - Green sliders should be adjusted by approximately equal amounts.  I believe the function of the slope sliders is to adjust the slope of the  green chart line to best match the slope of the star populations as shown by the colour - colour charts.   I agree that the purpose of the Red - Blue slider is to suitably balance the populations of Red and Blue stars and in this regard I was looking to achieve a slightly higher population of Red to Blue that I actually managed in your image but having said that many images that I see on eg Astrobin do not achieve this objective either.  Maybe with some more fine tuning of the parameters a better result could be achieved.  In any case I do not think you will find a set of CSC values that will apply equally to all images that you take with the same imaging set-up. Each image needs to be adjusted on its merits though I agree it is useful to have an idea of the starting values that are likely to achieve success.

I will be interested to hear if Mabula has a view on the best order to approach the parameter settings.  From my experience the available parameters are not completely independent variables so by changing one setting it is often necessary to make a subsequent change elsewhere.

At this stage I don't think there is a completely objective way to approach this.  I think you need to achieve a result that ultimately is pleasing to you and in this regard I try to get a result that approximates as best that I can get to (in my case LRGB) images that have achieved APOD or similar distinctions elsewhere.

Anyway have fun on your journey to astroimaging nirvana.

Regards

Mike

Let me have a go with it, he indeed is very busy at the moment. ;) I'm downloading it and will have a look.

Hi Vincent

Did you have any luck with the Star Color Calibration on my data?  

Hi,

Just to follow up my comment about a Green cast in the above image,  here is a version saved with slightly increased saturation after application of the Photoshop HLVG plug-in.  I think it is a marked improvement.

Mike

1551

Hi Mike. I agree with you, the first one had too much Green. The 2nd version is much better, although for me personally, i still find it a bit too green as well (but that could just be me!).

I suppose i should attach my final processed version as well. You can see it below. For this version, i had to use a stack that had no Star Color Calibration routine ran on it. Only then was i able to naturally (i.e without playing any funny business with the colors, such as with selective color adjustments) come to a version with the colors of the one below, which i personally really liked. For some reason, if i tried using Star Color Calibration, i could never reach this color balance later in processing. It just always looked off to me. So i figured i wasn't using the right settings, which is why i would like an experienced user of this tool to give it a whirl so i will know in future exactly what settings to use. 

1552

Hi Xiga,

I hope you won't think me presumptious but I've taken the liberty of downloading your data to see what I could achieve and maybe also improve my own processing skills.

The result I achieved is as follows:

1549

I hope you think this is reasonably decent though I fancy there is maybe still a slight green cast.

The steps I used were as follows:

1.  Batch modify, to remove the effects of frame rotation during image capture

2.  Remove LPC

3.  Calibrate Star Colours, the settings I used here are shown in the attached screen-shot.

1550

:  I found that the image was very sensitive to single steps changes on the Blue - Red slider at the -0.10 -  -0.11 setting.

4.  HSL selective colour - followed the steps in Part 6 of Mabula's Mosaic Tutorial Milky Way to Rho Ophiuchi but omitting step 3 and adding an extra step to slightly desaturate the blueness in the stars.

5.  Final adjustments to the Image Viewer setting at the RHS followed by save as JPG.

Hope this is a some value to you.  I enjoyed the practice at least.

Best Regards

Mike

Hi Mike

Of course i've no problem with you downloading the data to practice on :-) 

Thanks for having a go - i'm not sure though if i agree with your settings (although i'd like some expert input to be sure). It was my understanding that you should change both slopes by an equal percentage, and it looks like you changed the top slope much more than the bottom one. I'm also not sure if moving the Blue-Red slider towards Blue is correct. It looks to me like this leads to more blue stars than red, and i though it was supposed to be the other way around. In terms of the constants, i can't recall what i used myself, although i have a gut feeling they were much lower than yours (probably somewhere between -0.1 and -0.25 but i'm just guesstimating now!). 

Just to follow up my comment about a Green cast in the above image,  here is a version saved with slightly increased saturation after application of the Photoshop HLVG plug-in.  I think it is a marked improvement.

Mike

1551

I hope you won't think me presumptious but I've taken the liberty of downloading your data to see what I could achieve and maybe also improve my own processing skills.

The result I achieved is as follows:

1549

I hope you think this is reasonably decent though I fancy there is maybe still a slight green cast.

The steps I used were as follows:

1.  Batch modify, to remove the effects of frame rotation during image capture

2.  Remove LPC

3.  Calibrate Star Colours, the settings I used here are shown in the attached screen-shot.

1550

:  I found that the image was very sensitive to single steps changes on the Blue - Red slider at the -0.10 -  -0.11 setting.

4.  HSL selective colour - followed the steps in Part 6 of Mabula's Mosaic Tutorial Milky Way to Rho Ophiuchi but omitting step 3 and adding an extra step to slightly desaturate the blueness in the stars.

5.  Final adjustments to the Image Viewer setting at the RHS followed by save as JPG.

Hope this is a some value to you.  I enjoyed the practice at least.

Best Regards

Mike

Let me know how you get on  👍