VueScan - Output color space again

  • Thread starter Thread starter Jonathan
  • Start date Start date
J

Jonathan

Hi,

I noticed that the color tone of the preview and scan images in
VueScan changes when I select a different Output color space.

Obviously, different output (or embedded) color spaces will generate
different values for the same color, but in a correctly color managed
system, same images in different output (or embedded) color spaces
will appear the same on screen after going through the Monitor color
space transformation.

The Output color space option in VueScan definitely works well because
the same image saved in two different color spaces appear the same in
Photoshop 7.0. But in VueScan, they appear differently. It seems to
me that there is a problem in transforming the image to the proper
Monitor color space.

Thanks and Regards,
 
Jonathan said:
Hi,

I noticed that the color tone of the preview and scan images in
VueScan changes when I select a different Output color space.

Obviously, different output (or embedded) color spaces will generate
different values for the same color, but in a correctly color managed
system, same images in different output (or embedded) color spaces
will appear the same on screen after going through the Monitor color
space transformation.
Click to expand...

This is not true. because of differrent gammut of different color spaces.

And it is very stupid thing in many scanner software that it dosn't allow to
choose ICC output profile but have the set of predefined ptofiles.
 
Sorry, I might not have made myself clear.

I was referring to the set of colors that exist in a color space 1 and
also exist in another color space 2. A single color in this set, even
though numerically it may be represented as different color values in
the 2 color spaces, visually they must be identical. Before a color
embedded in a color space is sent to the monitor, it must be converted
to the monitor color space. So, if a software handles color spaces
correctly, this color, in 2 separate instances of different embedded
color spaces, must appear the same on the monitor.

The image that I used to test the output color space in VueScan is
just a regular portrait. Most of it colors are within the 2 color
spaces that I chose and the color space of my monitor. So, I was
expected to see the image, even thought in 2 different embedded color
spaces, appearing identically on my monitor.

Jonathan
 
Any taker of this question....

Essentially, the color tone of VueScan's preview and scan images in
the VueScan application changes when I select different output color
profiles. Most colors should remain unchanged on screen when an image
is tagged to different profiles except those out of gamut color, of
course. This, of course, assumes that an application is doing the
image conversion from the embedded color space to the monitor color
space correctly. I assume VueScan is doing this conversion as it
allows me to specify a monitor profile.

Jonathan
 
Any taker of this question....

Essentially, the color tone of VueScan's preview and scan images in
the VueScan application changes when I select different output color
profiles. Most colors should remain unchanged on screen when an image
is tagged to different profiles except those out of gamut color, of
course. This, of course, assumes that an application is doing the
image conversion from the embedded color space to the monitor color
space correctly. I assume VueScan is doing this conversion as it
allows me to specify a monitor profile.
Click to expand...

I cannot answer your question, but at least I have noticed the same
thing and I find it puzzling, too. Even more puzzling is the fact that
the "out of gamut" warning does not come off or even change at all, no
matter which output colour space I pick. Either something is broken,
there is something I do not understand, or my mother owns a goretex
jacket in a colour that doesn't exist in any known RGB space. :)

I could have sworn everything worked like I expected a while ago but
unfortunately, I have not kept any sufficiently old versions around to
verify that. Neither can I test with the very latest versions for
linux/libc-istic reasons, which means I cannot file a bug report right
now...

-- T
 
It could be due to the monitor rendering intent that is applied under the
hood in VueScan.

-J
 
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