color print question (profile/calibration) - am I an idiot?

[MasSi]

Am I fundamentally misunderstanding something with regards to paper profiling and color calibration etc?


consider this scenario:

I have some printer paper. My printer has calibrated this paper (HP DesignJet and the paper is a Canson Rag matte type paper)
I put a few colored squiggles on a sheet of this paper, with paints or marker, whatever.
I take a photograph using my Phase One IQ3 with even diffuse flash lighting from either side of the subject (The image was captured with a colorchecker also in the frame.)

Monitor is calibrated

In capture one I load in the image. turn off color correction, set the curve to linear Response and export out the image to the colorchecker software to generate an ICC profile based on this color checker passport image

back in capture one, I apply the profile to my captured image.

Next I export out (16bit tiff) to Qimage. Printer is set to manage colors and the paper type is set to the one used to put the paint on and photographed

finally I print. and its way off. its really dark.
diagnostic print from the printer suggests all inks/printheads are working correctly.


I was assuming, that once I applied the ICC in capture one, that the whiteness of the paper would be such that when printed, it would only print the colors, not print an image of the paper onto the paper if you know what I mean? I 'd accept it to be relatively close, not perfect. but what I am seeing is a very distinct difference in color for the paper portion of the image

 

[MartinN]

I made profiles with Profile Prism and IT8 targets, that were measured in the manufacturing, and used a scanner. However the color science in making a profile and applying a profile, for monitor soft proofing is a bit different, I think. Still, I am not completely satisfied with the profiles, I have made, but they take my prints a lot nearer what I want. Softproofing through a profile can be helpful, but nothing is completely accurate.

 

[Jan Brittenson]

I was assuming, that once I applied the ICC in capture one, that the whiteness of the paper would be such that when printed, it would only print the colors, not print an image of the paper onto the paper if you know what I mean? I 'd accept it to be relatively close, not perfect. but what I am seeing is a very distinct difference in color for the paper portion of the image

I haven't used Qimage since Qimage Pro, like 20 years ago. Not familiar with Qimage Ultimate or Qimage One. But it sounds like you photographed a print, and the output is a photograph of a print. I think you need to rethink the workflow if you want to use a camera for reproduction; it's a different thing altogether. In that case you should profile it as if it were a scanner and you need to set white and blackpoints based on the media.

The first question to ask is if the print looks like the preview in Qimage. If not, there's a missing or misapplied profile when printing from it. There could also be an issue with gamma vs linear; if you have a linear file tagged with a gamma it's possible that Qimage or more likely the printer driver ignores the gamma tag (perhaps thinking it's the gamma to which it was processed, stored purely for reference). The solution to these things is typically to render intermediate temporary files. If it looks dark in Qimage but fine in C1, then make sure Qimage uses the image color profile.

 

[anwarp]

I think I understand what you’re trying to do. Please correct me if I’m wrong.
Are you trying to profile the paper using the camera with the colour checker as a calibrated input device? In that case, you have a completely unknown set of variables with the printer output.
If on the other hand, you already have a profile for the printer and paper, the brightness of your monitor and the light source used to view the prin are very important.