Everything Is Very Red!

[gnomus]

I have recently purchased my PixInsight licence.  I'm pleased with the program, but I don't know if I have it set up correctly.  I use an astro-modded Canon EOS 600D.  When I load my stacked images into PixInsight and use the Screen Transfer Function everything is very red (and I mean very red).   I can get rid of this with DBE, but have found that the best way is to split the image into R, G & B channels, then use Linear Fit and then LRGB combination.  It seems odd that I should have to do this.  And it does of course add time to the processing.  I am becoming increasingly convinced that I have something set incorrectly.

I have attached a reduced version of an image to show what I mean.

[Zocky]

It is not  as big problem as it seems.
When applying STF, you can apply it with or without linked channels (chain icon on the upper left corner). That is just for viewing an image on screen.
When you start with processing, first you should apply Background Neutralization, then Color Calibration and then the rest of your process steps.
 

[Alejandro Tombolini]

See also here

[gnomus]

Thank you.  I'll have a play.

One thing I have noticed is that when I hover the mouse over a menu item a potentially useful help text box appears.  However, usually this text is cut off a certain way into the dialogue.  Is there any way to force PI to show the entirety of what is in the help box?

[topboxman]

One thing I have noticed is that when I hover the mouse over a menu item a potentially useful help text box appears.  However, usually this text is cut off a certain way into the dialogue.  Is there any way to force PI to show the entirety of what is in the help box?

I get the same thing every time. The simple solution is to mouse over another menu item and then quickly mouse over back to original menu item. It takes some practice but should work. A little inconvenient. It's been like that since day one on several of my computers.

Peter

[gnomus]

One thing I have noticed is that when I hover the mouse over a menu item a potentially useful help text box appears.  However, usually this text is cut off a certain way into the dialogue.  Is there any way to force PI to show the entirety of what is in the help box?

I get the same thing every time. The simple solution is to mouse over another menu item and then quickly mouse over back to original menu item. It takes some practice but should work. A little inconvenient. It's been like that since day one on several of my computers.

Peter

OK, I understand - it's a 'feature'.   

[gnomus]

OK.  I've been following the recommendation to use Background Neutralisation as a first step, but I am not sure that I am getting the desired result.  I have attached two photographs.  The first is what I achieve just doing a Background Neutralisation on my stacked image file, then a quick Histogram Transformation using the settings given in Screen Transfer Function (linked).  The second image shows what I achieve by splitting the RGB channels, then Linear Fit, then LRGB Combination and finally a Histogram Stretch using the STF linked settings.  As can be seen the BN version is still quite reddy-brown.  The Linear Fit seems to give me a better starting point.  It would be nice to know what I am doing wrong so that I can get a more efficient workflow.

Thanks for your continued interest.

[RickS]

You missed the second step, which is to apply ColorCalibration after BackgroundNeutralization 

[jerryyyyy]

I have found (and I am not sure everyone will agree) that if I do DBE (which includes background neurtralization) on each of the three RGB images and then do a LinearFit based on the G, when I combine the images in LRGBCombo often there is little need for color calibration.  In this case you need the STF with the link checked. 

[JoLo]

I do the DBE on individual RGB channels, but then I create a synthetic lum using ImageIntegration.  I then process the Lum Master, including linear noise reduction with MLT.  I then do a RGB combine, BackgroundNeutralization, ColorCal, linear NR with MLT.

I find this workflow gives me several improvements over what i used to do:

     *  No need to do DBE on the lum
     *  BN and CC work very well in tandem
     *  I never use LinearFit anymore
     *  I get a better SNR with the synthetic lum

What i have found works well for the BN/CC is being very careful with Preview placement for background and stars.  When you do, and don't do linearfit beforehand, there is little correction that occurs and you are left with a clean, balanced image. 

I no longer use MaskedStretch on my RGB image.  For both Lum and RGB, I stop short of aggressively stretching using HT and the brightness matches very well.  I then do not need LinearFit prior to LRGBCombine.

Anyway, works for me.

Joe

[gnomus]

Thanks everyone.  I will try the various suggestions.  Once I did Colour Calibration, Image 1 looked like Image 2, so that was the issue.

[jkmorse]

JoLo,

How do you overcome issues with nebulosity or targets like M51, which do not offer a solid white point for CC.  In those cases I follow the method described by Gerald, using LinearFit.  But would love to hear if you are using a different method, such as stars for the CC white point.  If so, could you go into a little detail on your process.

Thanks,

Jim

[pfile]

you can use the stars (that's what the "structure detection" setting is for in ColorCalibration's white reference).

but when working on a galaxy image you can use the entire galaxy as a white reference, or maybe a preview over the center of the galaxy. on average,  the galaxy will be white.

rob