VueScan Output color space

[Jonathan]

Hi,

Does VueScan allow user to specify an ICC profile as the Output color
space in the "Color" tab?

Currently, in the Output color space pull-down, I can choose from a
list of pre-defined color spaces, from Device RGB to ECI RGB, but I
don't see an ICC Profile option, like in aother color spaces'
pull-down menus.

Is an ICC profile option going to be supported in future version?

Thanks & Regard,

 

[Erik Krause]

Hello, Jonathan
you wrote...

Does VueScan allow user to specify an ICC profile as the Output color
space in the "Color" tab?

Currently, in the Output color space pull-down, I can choose from a
list of pre-defined color spaces, from Device RGB to ECI RGB, but I
don't see an ICC Profile option, like in aother color spaces'
pull-down menus.

Is an ICC profile option going to be supported in future version?

Why do you think this should be necessary?

Output color space is for transfer to your image processor only. It
should be wide enough to transport all image data. Since Vuescan
already supports some of the largest gamut color spaces (ProPhoto RGB,
CIE RGB) there is no need for additional color spaces...

 

[Jonathan]

Erik:

I actually want to save my image in a linear color space (gamma 1.0).
Through Photoshop, I have created an Adobe RGB Gamma 1 color space
(the important thing about this color space is gamma 1. Adobe RGB is
just a pick of convenience. As you mention, any color space big
enough for my purpose is fine). And I was hoping I could get VueScan
to convert my image into the gamut of Adobe RGB, but not to do any
gamma correction.

The reason of my having a gamma 1.0 image is to preserve as much color
information as possible during editing. I agree that eventually, when
the image is ready for viewing, I have to convert it to gamma 2.5
first. But before that, I would like to use a linear space for
editing.

Jonathan

 

[Erik Krause]

Hello, Jonathan
you wrote...

I actually want to save my image in a linear color space (gamma 1.0).

And why don't you simply set brightness to 0.4545 now you know that
vuescan does first multiply gamma and brightness values and after that
applies it?

Through Photoshop, I have created an Adobe RGB Gamma 1 color space
(the important thing about this color space is gamma 1. Adobe RGB is
just a pick of convenience. As you mention, any color space big
enough for my purpose is fine). And I was hoping I could get VueScan
to convert my image into the gamut of Adobe RGB, but not to do any
gamma correction.

Just use raw output. If you set 'Raw output with save' even infrared
clean is applied, so this should be pretty near to what you want.
Especially since there is no color conversion at all and therefore no
possibility to loose any information.

The reason of my having a gamma 1.0 image is to preserve as much color
information as possible during editing.

I wonder what kind of editing could be done, if you see no shadow
details because the image is too dark. And of course you know the
photoshop bug in the levels dialog gamma adjustment.

I agree that eventually, when
the image is ready for viewing, I have to convert it to gamma 2.5
first. But before that, I would like to use a linear space for
editing.

I always use 16 bit per channel tiffs for editing to preserve as much
color information as possible. Although I know the examples of Timo I
very much like to see what I do...

 

[Jonathan]

Hello, Jonathan
you wrote...


And why don't you simply set brightness to 0.4545 now you know that
vuescan does first multiply gamma and brightness values and after that
applies it?

Yes, I can do this, but the gamma value in the embedded profile is
still read 2.2 even though the color information is linear. I have to
assign the same profile with a gamma 1.0 profile in Photoshop.

Just use raw output. If you set 'Raw output with save' even infrared
clean is applied, so this should be pretty near to what you want.
Especially since there is no color conversion at all and therefore no
possibility to loose any information.

The raw output is not tagged, not even the device's profile. With the
raw file, I immediately lose the color reference. I don't have my
scanner's color profile (it is a Nikon LS-2000) that I can assign to
the image.

Do you know a way to extract the scanner's color profile from VueScan?

Thanks.
Jonathan

 

[Erik Krause]

Hello, Jonathan
you wrote...

Yes, I can do this, but the gamma value in the embedded profile is
still read 2.2 even though the color information is linear.

You don't need to embed the profile. Just uncheck 'Tiff profile' on
output tab.

I have to
assign the same profile with a gamma 1.0 profile in Photoshop.

Another way would be to use tificc (contained in the lcms profiler
package) to assign it. You will have to create a batch file and use it
as 'external viewer' in vuescan. You can even create a photoshop
droplet .exe file and use it as 'external viewer' (at least it worked
for me with PS 6.0 on Windows 2000).

The raw output is not tagged, not even the device's profile. With the
raw file, I immediately lose the color reference. I don't have my
scanner's color profile (it is a Nikon LS-2000) that I can assign to
the image.

If you installed Nikonscan there should be a couple of profiles
somewhere on your computer. For me it is
C:\Program Files\Common Files\Nikon\Profiles
May be this helps, but I never tried to do anything with these
profiles.

Do you know a way to extract the scanner's color profile from VueScan?

No. But you can make any relevant processing in linear space and use
vuescans 'scan from disk' feature to apply scanner profile and convert
to gamma 2.2 space.