unable to get the overlay mask to show up in red color

[rockyraccoon]

here is an interesting one:
for a few weeks now, when I overlay masks on single-channel images they show up in grey instead of the usual red.
This is despite the fact, that in global preferences I have set the default mask rendering mode to "red".

And here is something even more interesting. If I launch a second instance of PI from the console using !!$PXI_COREDIR/PixInsight -n
then in that instance, the masks show up in RED.

What's going on?

[Juan Conejero]

This cannot be reproduced, and nobody else has reported a similar problem on any platform. Probably you have changed some mask rendering settings inadvertently.

And here is something even more interesting. If I launch a second instance of PI from the console using !!$PXI_COREDIR/PixInsight -n
then in that instance, the masks show up in RED.

Each running instance of PixInsight uses an independent set of application settings, so this is the expected behavior.

[Philippe B.]

Hi Juan

I got similar issue both windows10 and OSX versions with some XISF images. Not all ! I can reproduce on every machine I have (OSX or Windows), last version of PI.


Here, image SIGNAL with STF applied should be "red". If you click on purple mask color icon, image becomes white.





Here are the 2 files you can download



http://astroccd.eu/images/SIGNAL.xisf

http://astroccd.eu/images/MASK.xisf


Cheers
Philippe

[Juan Conejero]

Hi Philippe,

The problem with these images is that they have a grayscale ICC color profile assigned (namely 'Profil niveaux de gris lineaire'). Since the color transformation defined by this profile forces a grayscale representation of the image, the mask cannot be represented as a red overlay, but only as a gray overlay. With this profile assigned, the only mask rendering options that can be effectively used are 'replace' and 'multiply'.

I don't know why you have assigned such profile to these images, but with 99.99% probability, this is incorrect. On one hand, I have serious doubts about the correctness of this supposedly linear profile. More importantly, this profile won't provide you with a valid screen representation of anything valid from a color management point of view. Furthermore, as soon as you get a nonlinear screen representation with STF, or when you apply any nonlinear transformation (HT, CT, etc.), a linear profile can't make any sense at all.

I strongly recommend you cease using this color profile, since it won't let you see the true image that you have. If you insist in using it, press F11 to disable color management and then you'll be able to see red mask overlays again.

In PixInsight you can use any color profile, including grayscale and RGB profiles, with grayscale images. If you want to work in a color managed environment with grayscale images (after a nonlinear transformation, of course), you can use a standard color profile such as sRGB or Adobe RGB, among many others.

[Philippe B.]

Hi Juan
that's right, I don't know WHY the grey scale profile has been set. I always select AdobeRGB on all "colormanagement" options ! So I don't understand too why it takes a grey scale profile !




For this correctness... it could be a star mask (same way iven if the mask is different), an intensity mask (to make a denoising on low levels on linear images), or make a correction on a LINEAR image, you will need a NON-LINEAR MASK (or a star mask)


I often use mask on linear images...

[rockyraccoon]

Thank you Philippe!
Indeed, in my case the color profile for grey images was set to "generic gray gamma 2.2" - once reset to to my color display profile, the mask overlay returned to "red".
Juan: I don't think that applying color profile rules to masks makes any conceptual sense - but I'm glad that I was able to get this resolved.