Grey image

[Dave-H]

Hi again, the file associations are working fine again in Windows XP now, thanks!
However, there is another issue, which was also there in 2.42.
Some (but not all) of my greyscale JPG and PNG images are appearing bright red or magenta instead of black and while when viewed with XnView.
This was not the case with the older version that I was using.
Is this a settings problem or a compatibility problem?
I've attached a copy of one of the affected files.
Thanks, Dave.

Chequebook Pages.jpg

[xnview]

i can't reproduce, could you post a screenshot?

[Dave-H]

Thanks Pierre!
I've attached a couple of screen grabs.
The first is the image I attached last time, the second is a large PNG image that shows the same problem, but is sometimes red and sometimes magenta, as here. The first one, the JPG, always seems to be red.
There are some others with the same problem, but I haven't been able to identify what they have in common!
They print fine, and their thumbnails are fine, it's just the normal view in XnView which is wrong.
Cheers, Dave.

Image1.jpg

Image2.jpg

[xnview]

really strange could you send me your xnview.ini

[Dave-H]

Here it is!
It's in a zip file as the forum will not allow ini files as attachments it seems.

xnview.zip

[xnview]

i can reproduce now

[Dave-H]

That's good!
Is that only when using my ini file?
If so I take it that it's presumably a settings problem somewhere then.

[xnview]

in you xnview.ini, you can change UseAlpha=1

[Dave-H]

Thanks Pierre, that has fixed it completely!
Where is that setting in the GUI as a matter of interest, and is there any downside to setting it to 1?
There is also an "IgnoreAlpha" setting in the ini file, which on one of my installations is set to 0, and the others it's set to 1.
Which is the best setting for that parameter?
Cheers, Dave.

[XnTriq]

Where is that setting in the GUI as a matter of interest, and is there any downside to setting it to 1?
There is also an "IgnoreAlpha" setting in the ini file, which on one of my installations is set to 0, and the others it's set to 1.

Hi Dave (-:

• UseAlpha=0/1
  • View mode: View → Use alpha channel
• IgnoreAlpha=0/1
  • Tools → Options... → General → Operations → Ignore alpha channel

And here's an image with an alpha channel for you to test the effects of these settings: logo.png

[Dave-H]

Thanks, that's extremely helpful!
The logo displays properly with IgnoreAlpha=0 and UseAlpha=1, and my greyscale images all display fine with those settings too.
I'm not sure why you would want to use any other settings, but I guess they're useful for testing purposes.
Thanks again, much appreciated.
Cheers,
Dave.

[XnTriq]

I'm not sure why you would want to use any other settings, but I guess they're useful for testing purposes.

2.png (optimzed) and 1.png look identical if Ignore alpha channel is disabled and Use alpha channel is activated, but when you turn off Use alpha channel, XnView reveals the otherwise hidden differences underneath/behind the alpha channel mask in view mode as well as the thumbnails.

See also:

• Transparency & alpha
• Editing an images loses its transparency
• Transparency — Straight vs. premultiplied alpha

[Dave-H]

Thanks!