Jump in overall brightness when exporting from PixInsight to Photoshop

[B4silio]

Hi!

In my workflow for narrowband images I do my first processing with pixinsight (Stacking > Deconvolution > Stretching) and then move to phtoshop for Luminance Matching, color combination and post-processing.

I'm pretty happy with the results I get, but I'm always bummed by an issue I get when switching from PI to PS : The image I export from PI (Tiff, 16bit) appears darker in PI than when I open it up on Photoshop (the image below is a side-by-side screenshot of the exported image re-opened in both software). This means that if I do a stretching that looks good to me in PI, it will be an overbrightened mess when opened in photoshop. I've learned to guesstimate how dark I need to make my stretch in PI so that it will appear ok in photoshop (and then I take it from there with CameraRaw), but this means that spending time with something like GHS is rather fruitless because the final image I open in Photoshop will look nothing like what I might have spent a while fine-tuning in PI. 

Is my PI somehow displaying the image incorrectly? Or is photoshop reading the exported tiff badly? I work extensively on PS for my daily job and use a calibrated monitor so I trust implicitly what PS is showing me. But I imagine it might be something iffy in the export + import process?

Any ideas are welcome!

Edited February 7 by B4silio

[Elp]

Are they both using the same colour spaces?

[B4silio]

1 hour ago, Elp said:

Are they both using the same colour spaces?

Thx for the question, they're grayscale!

However you pointed me in the right direction!

Switching the color profile from default to sGray (the mono equivalent to the sRGB ICC profile), the image displays very close to what I have in pixinsight! I didn't think about it since I don't usually manage ICC profiles on grayscale images, but it definitely makes a difference! 

Thank you!

[Elp]

The reason I mentioned colour space is because in the PS screenshot above you're working in RGB 16 bit mode, not greyscale.

[B4silio]

2 hours ago, Elp said:

The reason I mentioned colour space is because in the PS screenshot above you're working in RGB 16 bit mode, not greyscale.

yeah that's because I'd already layered out the 3 channels for color combination (the name of the doc was indeed misleading). Nevertheless, your comment did end up getting me to the solution, so thanks again!

[h107]

That image looks amazing! I would 100% like to see the finished result on that.