Mike Chaney's Tech Corner

Does anybody know whether soft proofing in Qimage also simulates the paper white (as you can do in PS)?

Christian

I don't know the definitive answer to this question, but it begs the question:

What value a profile for a specific paper that is not made using the specific paper profiled? Logically it would seem that an accurate profile MUST take the colour or shade of the paper into account else the profile is of limited value.

However I am frequently wrong, and events are not always logical, so await the definitive word from Mike on this issue.


Roy Sletcher

No, there is no setting for paper type.
Terry

Roy,

A printer profile is there in the first place to translate you image gamut as good as possible to the gamut possible with the inks and paper it is made for. That print will build on the paper white physically available. In profile creation there is often a choice to keep the image neutrality absolute or starting from the paper white, the last is almost never neutrally white. In both cases the profiling compensates (subtracts)the physical existence of the paper white in the gamut but differently. That sums up the printing device side of the profile. For soft proofing another, related part of the profile is used. In the profile the paper white spec is available too and has to be used (added) for paper white simulation. If the soft proofing feature of the application doesn't try to simulate the paper white on the display then that doesn't tell anything about how good the profiling to the print works. In advanced profile editors the two profile parts can be edited separately to get the display and print more related. Something that should only be done when you have done everything to get your display and printer/print media properly calibrated and profiled.

If Qimage does a white paper compensation by default it is very little if compared to the difference in the whites Photoshop creates on the switch between original and softproof with paper white compensation on.  I do not see it. Select a profile for a warm paper like German Etching. Select a profile assigned image and switch between original and softproof with space and keep your eyes on an RGB 255 area.

I prefer print proofs anyway.

As far as I know soft proofing doesn't have a standard and it is the developer who has to brew the mix.


met vriendelijke groeten, Ernst Dinkla

Try: http://groups.yahoo.com/group/Wide_Inkjet_Printers/

Thanks for the replies.
It's not because there is no option for paper type, that it cannot simulate the white of the paper, it may do so automatically. As Ernst pointed out, the info on the paper white is contained in the profile but not always used. Photoshop can soft proof with/without using paper white. So I was wondering whether Qimage actually does it with or without. I agree with Ernst, when comparing to PS, the soft proof in Qimage looks more as if paper white is not used. Maybe Mike can tell us.

Christian

Hi Ernst,

Thanks for your patient and well written explanation. I have learned much from this and your previous posts about other subjects on this site.

However, the one point that still bothers me is the fact that the profile is made from a STANDARDISED TARGET print which theoretically includes and bias in paper colouration. For example if the paper had an exceptional warm tone, this would be included in the readings made by the spectro tool when calibrating the values for the profile of that specific paper. Hence the need for additional paper white setting appears redundant as this would have been allowed for in the calculation of the profile values.

Having said that, I should mention I have no specialised knowledge in this area, and was relying primarily on logic and common sense. This usually stands me in good stead, and oftentimes deep water. This may be one of those occasions. The fact that my custom profiles reasonably well match the Qimage soft proof may be more ignorant luck than skill.

Then again my print workflow always includes a couple reduced size test image on critical colour/tones.

Thank you for the Yahoo printer link. I will spend some time digesting the content.


Roy

Roy,

The preference in profiling is to not compensate (for absolute neutrality sake) the off white paper color by printing ink there, it would reduce reflectance more. The eye adapts to the base white and accepts/compensates that gamut bias as long as there is no strong competition to the eye with another cooler print next to it or white background. The same approach is used for the normal softproof to a degree, the white will be the (calibrated, monitor profiled) monitor white, the gamut however influenced by the paper above the paper white. With paper white simulation there will be a shift in the RGB 255.255.255 from the monitor white, that influence decreasing above the white. Similar for black ink simulation. So there is a print representation in the normal softproof but not totally. In fact is all a simulation as the additive color mixing RGB monitor isn't like subtractive mixing CMY(K) ink on the print.

There's an analogy between the color temperature of your monitor and the viewing light for proofs. The color temperature doesn't have to be equal to do the job. The eye adapts. There is also the Kruithof curve, with less light the preference is for a warmer light. A lot of the cheaper LCD monitors can not be dimmed so in that case it is better to use say 6500K or the default which will also be cooler than 5000K. The viewing light usually stays below 5500K and there's now a tendency for photography to go down to 4700-4100K in relation with the lighting at home or in galleries. A match on color temperature between viewing light and monitor will be difficult, but the eyes adapt.


met vriendelijke groeten, Ernst Dinkla

Try: http://groups.yahoo.com/group/Wide_Inkjet_Printers/

There is also a good article on this topic here:

http://www.outbackphoto.com/printinginsights/pi045/essay.html (http://www.outbackphoto.com/printinginsights/pi045/essay.html)

go down to the article "02/01/2007 Profiling the Advanced Black and White Mode"


Christian