What exactly does 'Simulate paper white' do?

[Hening Bettermann]

In a recent thread about screen to print match
http://forum.luminous-landscape.com/index.php?topic=120611.0

the question of simulating paper white was raised. In PhotoLine, which I use for editing, this option can not be chosen in the softproof dialog. On the german help forum, I asked if this option maybe was baked in and could not be de/selected. Here is the answer of one of the developers, my translation: (for those speaking German, the original thread is here: http://www.pl32.com/forum3/viewtopic.php??p=42757&sid=4825dfe9062dc5920d147aba4da8867a#p42757)

"Since I don't know what 'Simulate paper white' does, I cannot answer this. I can only tell you what PhotoLine does when softproofing (under Mac OS). 3 profiles are involved:
-the image profile (with its rendering intent)
-the profile for the device to be simulated [here: the paper profile of my print service]
-the profile of the output device (screen or printer) [here: my screen].

In the first step, conversion is performed from the image color space into the color space of the device to be simulated, using the chosen option for black point compensation and rendering intent.
In the second step,  the conversion is done from the color space of the simulated device to the color space of the output device, without blackpoint compensation. If the output device is the screen,  relative colorimetric is used as the rendering intent; other wise absolute colorimetric."

Question:
Does this procedure take paper white into account? And if not, what does the Photoshop option do?

[TonyW]

No experience Photoline but in PS and LR yes turning on simulate paper does exactly that and attempts to display an image to represent what you will see in the final print

Your ICC paper profile will contain a White Point Tag.
 
Turning this on the application simulates the papers white point as close as possible on screen.  Turning it off you will see the white point of your monitor under current conditions which will not be representative of paper white

Attachment shows the effect of switching the simulation on or off

[digitaldog]

What the profiles are doing in terms of a soft proof:


•Simulate Paper Colorand Simulate Black InkOff: This produces the
relative colorimetric intent with Black Point Compensation.
•Simulate Black Ink: This produces the relative colorimetric intent
without Black Point Compensation.
•Simulate Paper Color: This produces the absolute colorimetric intent
(no Black Point Compensation).

[nirpat89]

Turning this on the application simulates the papers white point as close as possible on screen.  Turning it off you will see the white point of your monitor under current conditions which will not be representative of paper white

I always had this thought:  Why is the paper (non)white not taken care of in the profile itself.  Doesn't the profile know what (255,255,255) is printed as and should it not be reflected when you do the soft proofing?  Why do other colors change when the "paper simulation" is turned on.  They too are the part of the profile, no? 

I am sure there is a simple answer...
 

[TonyW]

I always had this thought:  Why is the paper (non)white not taken care of in the profile itself.  Doesn't the profile know what (255,255,255) is printed as and should it not be reflected when you do the soft proofing?  Why do other colors change when the "paper simulation" is turned on.  They too are the part of the profile, no? 

I am sure there is a simple answer...
 

The paper white is described in the profile itself otherwise soft proof will not work as well as hoped for.   You should see the paper white change in soft proofing to reflect the visual appearance of the actual print media.  This is also the case with other colours, the change reflecting the print medias ability to reproduce colour which can be massively different to viewing on your monitor without soft proofing initiated.
Click on the image posted and wait a few seconds to see the change to simulation on and off. 

[Hening Bettermann]

Thank you all for your answers.
Maybe I need to expand my question:
-Is the PhotoLine  procedure a "full fledged" softproof including the paper color? Tim Lookingbill questioned this, but it seems to be if I understand you right.
-Which implications has it, that Photoline allows a choice of black point compensation for the first step, but not for the second? I think to avoid that the black point compensation is used twice?
-And which implications has it, that in the second step, rel col is used for the screen, but absolute colorimetric for printers?

It looks to me like Photoshop/Lightroom offer these options to be chosen independent of each other, leaving it to the user to know and select the right one for the purpose; while PhotoLine has certain combinations baked ind and excludes others.

Please help me to look through this. Ultimately, I would like to be able to describe what both programs to in a common terminology. Eg: is the Photoline procedure the equivalent of PS with paper simulation?

[nirpat89]

The paper white is described in the profile itself otherwise soft proof will not work as well as hoped for.   You should see the paper white change in soft proofing to reflect the visual appearance of the actual print media.  This is also the case with other colours, the change reflecting the print medias ability to reproduce colour which can be massively different to viewing on your monitor without soft proofing initiated.
Click on the image posted and wait a few seconds to see the change to simulation on and off.

Tony, Hi: 

I understand the paper white is incorporated in the profile.  I do see the difference in your illustration.  But what I was trying to ask was why does one have to invoke specifically the "paper white and ink" in order to use this info.  Why is it not in the part of profile that maps the input-to-output data so it is reflected when you select the profile and rendering intent in "customize Proof Condition" in Photoshop.  If I am making my profile, when I make measurements with a spectro/colorimeter, am I not measuring the color which is the result of both the ink AND the paper.  How do these two get separated? and why?

:Niranjan.

P.S. I am probably hijacking OP's thread, so I will let it rest now...

[digitaldog]

Thank you all for your answers.
Maybe I need to expand my question:
-Is the PhotoLine  procedure a "full fledged" softproof including the paper color?

DO you see a difference with it on (you should)? Does it match Photoshop (it should)?

[Hening Bettermann]

to nirpat89:
No you are not hijacking at all. The answer to your question
"But what I was trying to ask was why does one have to invoke specifically the "paper white and ink" in order to use this info.  Why is it not in the part of profile that maps the input-to-output data so it is reflected when you select the profile and rendering intent"
will most likely contribute to clarification and to making these 2 programs' descriptions of softproofing comparable.

[Hening Bettermann]

to Andrew:
Yes I see a difference, but it seems to be about contrast (shadows), not color. As for PS, I don't have it installed, so I can not compare. (and I'm not in the CC).
The print I had produced using the softproof was off in color, too yellow. Maybe this is why?
I have now tried 2 different profiles, the one I actually used (Epson Premium Glossy) and Hahnemühle Photo Rag Baryta. They result in different degrees of contrast change, but not in color. So something is wrong here.

addendum: these 2 profiles are from 2 different print services.

[digitaldog]

to Andrew:
Yes I see a difference, but it seems to be about contrast (shadows), not color.

Exactly what one expects.
You see a difference, it's working, and short of a bug in your product, it should match the soft proof using the same settings from the same profile in other ICC aware products that have such soft proofing.

[Hening Bettermann]

So it's working. But what about the color? Why is there no difference, and is that why the print is yellow?

[digitaldog]

So it's working. But what about the color? Why is there no difference, and is that why the print is yellow?

Paper White! Now that isn't to say the profile is 'correct' (we'd have to do some measurements) or your display white point isn't nailed but the profile predicts a warm paper white.

[TonyW]

Tony, Hi: 

I understand the paper white is incorporated in the profile.  I do see the difference in your illustration.  But what I was trying to ask was why does one have to invoke specifically the "paper white and ink" in order to use this info.  Why is it not in the part of profile that maps the input-to-output data so it is reflected when you select the profile and rendering intent in "customize Proof Condition" in Photoshop.  If I am making my profile, when I make measurements with a spectro/colorimeter, am I not measuring the color which is the result of both the ink AND the paper.  How do these two get separated? and why?

:Niranjan.

P.S. I am probably hijacking OP's thread, so I will let it rest now...

Hi Niranjan
On the face of it it would seem to make sense once in soft proofing mode to automatically switch Paper White and Ink to On and may be not even have the Off option?

TBH I do not know the underlying reasoning for this behaviour - soft proofing has always worked very well for me with simulate paper and ink turned on (so not broken and no attempt made to fix it  ). 

Over the years I have seen odd comments that simulate paper and ink does not work correctly or that switching off gives a better result (at least with certain paper types)! 

This may indeed be the case for the individual user and if I was to think of a reason or two why this should happen my thoughts would first stray to the validity of monitor calibration and then the quality/accuracy of the ICC profile for a particular paper and viewing/lighting conditions for the print. 

Having said that there may be a better explanation of why?

[Doug Gray]

Biggest issue using show paper white is when you have OBAs present. Most viewing booths aren't compliant with the graphics industry ISO spec. which has enough uV to make M1 the best choice for profiles. The ones most of use use have relatively little uV and M0, the default for most profiles over specs the amount of uV these viewing booths have. I'm not sure about the uV content of Solux but it potentially has a decent amount of uV and so M0 or M1 might work well with it. Andrew Rodney likely has specific info on which M to use with Solux.

The result can be pretty unsatisfactory if there isn't a match with uV and you have OBAs. Show paper color works well with low uV setups with all papers if you use a profile generated with M2 (uV cut).

[Eric Myrvaagnes]

Another reason to avoid papers with OBAs.

[digitaldog]

But what I was trying to ask was why does one have to invoke specifically the "paper white and ink" in order to use this info.

To get a closer print to display match! To account for the contrast ratio of the print, not the display (per se depending on calibration). To show the effect of paper white on the image IF the profile is doing a good job of doing so (see Doug's point about OBAs etc). Ditto for black.


I keep the simulation option OFF when I decide which rendering intent per image I prefer. I turn it on when I want to see, in FULL SCREEN MODE, the closest preview of what the print should look like, viewed next to the display, then make output specific visual adjustments IF necessary.

[TonyW]

Doug, Andrew good info thanks 

[Hening Bettermann]

Andrew
>Paper White! Now that isn't to say the profile is 'correct' (we'd have to do some measurements) or your display white point isn't nailed but the profile predicts a warm paper white.
TonyW
>This may indeed be the case for the individual user and if I was to think of a reason or two why this should happen my thoughts would first stray to the validity of monitor calibration and then the quality/accuracy of the ICC profile for a particular paper and viewing/lighting conditions for the print. 

Hm. How could I know the validity of my monitor calibration? There is an option to validate the profile, using the same software that created it, so how is the validation of this validation? Andrew has earlier called it a 'Feel-good-button'. How can I check the white point of the monitor profile?
Viewing conditions for the print: I have calibrated the monitor to D50 and have established D50 roomlight not Solux but Yuji,
 
https://store.yujiintl.com/collections/high-cri-led-lights/products/bc-series-a60-high-cri-remote-phosphor-led-bulb-unit-2-pcs?variant=27740384775

even though not enough of it.

The print looks rather yellow/brown, like it had spent to much time in the fixation bath. I'll try to simulate the amount on screen when I'm back home in some days, I'm on the road right now.
The paper in question is Epson Premium Glossy. It does contain OBAs, not sure how much of them.

[digitaldog]

Hm. How could I know the validity of my monitor calibration?

It matches the soft proof (with good profiles).