Strange things happening after proofing

[alain]

Hi

I do see some strange things after using the print proofing button and back.

If I use kodak prophoto as working space and image space I get the expected result, but :

When I open an image in adobe RGB, soft proof and disable it again, the image turn blueish. This makes the soft proofing button not usable for adobe RGB images.

It took me a longer time to see because I use prophoto and 48 bit tif's myself.

Alain

[Dieter Mayr]

Alain

What settings do you use exactly to get this blueish cast?
My undterstanding is to use a output colorspace as proof profile, like a printer profile.
If you should use a colorspace like AdobeSRGB as proof profile, can you explain please why you do that ?

[alain]

Some more info:

Color management settings :
----
working color space : Kodak ProPhoto RGB
assumed file profile : none
On profile mismatch : Ask only on mismatch
Monitorprofile : x (after hardware calibration) = close to sRGB
Monitor rendering intent : Preserve Identical Colors and White Point

Proofing profile : specific paper
Proofing Rendering Intent Preserve Identical Colros + Black Point compensation
Monitor Proofing rendeing Intent : Maintain full Gamut
----

embedded icc profile inside the image :

a) Kodak Prophoto RGB and 16 bit (most of my "important" images)
-> ok

b) Adobe RGB and 8 bit (snapshots or images that I print for friends) and no conversion to Kodak ProPhoto RGB.
The problem occurs (different images from different people).

[Dieter Mayr]

Alain

I have tried with exactly your settings on my system, i do not see any color cast when switching between softproof and not, no difference if i let the image convert to Working CS or not.
My monitor profle is very close to sRGB, too, created with a measuring device.
Pronter profiles are also self made with the spyder print tool.
Can it be it is a problem with either your printing or monitor profile ?
As your monitor profile is close to sRGB, maybe you can try with using sRGB for the monitor profile for a test.

[alain]

Alain

I have tried with exactly your settings on my system, i do not see any color cast when switching between softproof and not, no difference if i let the image convert to Working CS or not.
My monitor profle is very close to sRGB, too, created with a measuring device.
Pronter profiles are also self made with the spyder print tool.
Can it be it is a problem with either your printing or monitor profile ?
As your monitor profile is close to sRGB, maybe you can try with using sRGB for the monitor profile for a test.

Hi Dieter

I very much doubt a problem with one of the profiles, because they work with Qimage and pwp works with prophoto.
It's also strange that the problem doesn't occur with the first opening. However if I close the image and open another one from pwp (without closing pwp) the problem is there from the opening, aka without a switch to proofing and back.


Alain

[alain]

Alain

I have tried with exactly your settings on my system, i do not see any color cast when switching between softproof and not, no difference if i let the image convert to Working CS or not.
My monitor profle is very close to sRGB, too, created with a measuring device.
Pronter profiles are also self made with the spyder print tool.
Can it be it is a problem with either your printing or monitor profile ?
As your monitor profile is close to sRGB, maybe you can try with using sRGB for the monitor profile for a test.

Hi Dieter

I very much doubt a problem with one of the profiles, because they work with Qimage and pwp works with prophoto.
It's also strange that the problem doesn't occur with the first opening. However if I close the image and open another one from pwp (without closing pwp) the problem is there from the opening, aka without a switch to proofing and back.


Alain

After changing the monitor profile to sRGB the problem was "gone" and this was easily reproducible.

I'll make a new profile and see what's the result.

BTW. It's a strange error.

[alain]

Alain

I have tried with exactly your settings on my system, i do not see any color cast when switching between softproof and not, no difference if i let the image convert to Working CS or not.
My monitor profle is very close to sRGB, too, created with a measuring device.
Pronter profiles are also self made with the spyder print tool.
Can it be it is a problem with either your printing or monitor profile ?
As your monitor profile is close to sRGB, maybe you can try with using sRGB for the monitor profile for a test.

Hi Dieter

I very much doubt a problem with one of the profiles, because they work with Qimage and pwp works with prophoto.
It's also strange that the problem doesn't occur with the first opening. However if I close the image and open another one from pwp (without closing pwp) the problem is there from the opening, aka without a switch to proofing and back.


Alain

After changing the monitor profile to sRGB the problem was "gone" and this was easily reproducible.

I'll make a new profile and see what's the result.

BTW. It's a strange error.

New profile doesn't change it.

Changing Monitor rendering intent from "Preserve Identical Colors and White Point" to "Preserve Identical Colros + Black Point compensation" does change it, blueish cast is gone.

Two conclusions :

a) pwp or lcms is doing something different after hitting the proofing button while running. Which is correct?

b) It's no problem with prophotoRGB, but with adobe RGB and sRGB. One of the differences is that prophoto RGB has D50 instead D65 for the other two..., which could account for the blueish cast.
A quick look on the internet gives some posts about the eye one display and D50, I'll look into it.

[jsachs]

Using Preserve Identical Colors and White Point is not a recommended choice for monitor rendering intent. By preserving the white point you will be passing through the white point of the original image. This in turn depends on the profile with which the image is tagged, so if the image uses a profile with a D50 white point and you view it with a monitor profile that has a D65 white point you will introduce a color cast. I recommended always using Maintain Full Gamut for monitor rendering intent.

[jsachs]

By the way, I also do not recommend Kodak Pro Photo as a working color space unless all your images are 16 bits/channel as this color space has such a wide gamut that most of the colors in a normal image will be compressed into the center part of the gamut and you will be wasting a lot of useful saturation levels. This is OK if you have a 16-bit image with levels to spare but could cause some color posterization for 8-bit images.

[alain]

By the way, I also do not recommend Kodak Pro Photo as a working color space unless all your images are 16 bits/channel as this color space has such a wide gamut that most of the colors in a normal image will be compressed into the center part of the gamut and you will be wasting a lot of useful saturation levels. This is OK if you have a 16-bit image with levels to spare but could cause some color posterization for 8-bit images.

You're 100% correct : My Kodak Pro Photo images are always 16 bit (thus rather big). I never use Kodak Pro Photo on 8-bit images.