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Author Topic: Soft Proofing - Simulate Paper Col question  (Read 1783 times)

FrankG

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Soft Proofing - Simulate Paper Col question
« on: April 05, 2022, 09:31:21 am »

This question is regarding print/display luminance matching. I understand that the soft proof can show out of gamut col.

Everything I've read says to un-check the Simulate Paper Col box. Why not? See the extracts quoted below the post.

I have a calibrated iMac display (xrite i1- D65, 2.2, 90) and a col corrected viewing booth (pantone). I have calibrated to a low-ish luminance value (90) to compensate for the screen being too bright resulting in slightly too dark prints (I use a printer/paper/ink profile in the Ps print dialog).
Generally, I also raise my midtones by about 10 points with a curve prior to printing & this seems to compensate (maybe its for over inking effect?) and it gives me satisfactory results.

I recently sent a bunch of images to a pro lab for c-type printing (Fuji Matte Maxima- a warmish paper) and used their custom icc profile for soft proofing the paper.
The prints are a little too dark.

However, if I go back to the file on my display, with the print alongside, and look at the soft proof again (Perceptual & Bl Pt checked as per lab instructions), and if I toggle Simulate Paper Col, then the display matches the print.

So, my questions are - is  checking the Simulate Paper Col box never to be done, why not? Or could/should it be done on a paper boy paper basis as per my above experience?
I obviously want to hit the mark and not waste paper, ink, or lab costs + wait for a lab print to be done before finding out that it's slightly too dark.

What do you advise?
Simulate Paper col on or off
Perhaps lower Luminance value further to 80.

Thanks

Here's what I found to explain what it does -
From Red River - "So the white you will see is the white point of your monitor, not the print. When turned on, the simulation uses the paper's white point. In short, the system tries to replicate the actual white shade of the paper you are using."
From Cambridge in Col - "Simulate Paper Color. This setting converts the image's on-screen white to match the color temperature of white on paper (which is equivalent to an absolute colorimetric conversion). In addition, this also compresses the dynamic range of the on-screen image so that it matches the narrower range in the print (similar to the above "black ink" setting), but it does so by also decreasing the on-screen intensity of white. When paper color is checked, the black ink setting is therefore usually unavailable (since the on-screen dynamic range is already being compressed)."
« Last Edit: April 05, 2022, 11:58:45 am by FrankG »
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digitaldog

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Re: Soft Proofing - Simulate Paper Col question
« Reply #1 on: April 05, 2022, 11:57:08 am »

A soft proof cannot show out of gamut colors (colors that are out of display gamut). If they fall outside display gamut but exist in the output color space, you can't see them.
If everything you've read says un-check the Simulate Paper Col box, you're reading the wrong stuff**!  :D
The DR of the display is very often far exceeding the DR of the print. The Simulate options provide a more 'accurate' (visually matching) soft proof because it takes paper white and black ink into account. It may look flatter and uglier (Jeff Schewe famously calls this option the "Make my image look like crap button") but reality can suck sometimes.
When you wish to compare the print next to the display for a match, you want that check box ON:

As for your 'pro lab', if they do not allow you to actually convert to the output color space, based on the rendering intent you select and using the profile you provide, they are not as professional (in terms of color management) than you think they are and if the prints are 'too dark' (compared to the display), part of the issue is they do not allow you to actually use the profile as intended.
But this is all summed up here, so just watch:

Why are my prints too dark?
Why doesn’t my display match my prints?
A video update to a written piece on subject from 2013
In this 24 minute video, I'll cover:

Are your prints really too dark?
Display calibration and WYSIWYG
Proper print viewing conditions
Trouble shooting to get a match
Avoiding kludges that don't solve the problem


High resolution: http://digitaldog.net/files/Why_are_my_prints_too_dark.mp4
Low resolution: https://youtu.be/iS6sjZmxjY4

**Cambridge in Col  (ignore this site, filled with misinformation). A comment here from a person who knows what he's talking about had me in stitches when I read this, so true:
https://forum.luminous-landscape.com/index.php?topic=120665.msg1004366#msg1004366
Quote
I wonder how many people reading that link realize the image they incorrectly tout as the "Profile Connection Space" is actually the human gamut CIEuv chromaticity graph?  Might as well have a cat picture.
« Last Edit: April 05, 2022, 12:00:15 pm by digitaldog »
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FrankG

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Re: Soft Proofing - Simulate Paper Col question
« Reply #2 on: April 05, 2022, 12:49:46 pm »

Thank you for this. I watched the audio/video & will need to watch again (several times) to absorb it all.
The first thing to establish is how to measure my viewing booth light to ensure I am viewing the prints under sufficient/correct illumination.
My viewing booth does not have a dimmer as yours does. It has 3 switches which activate 3 different col temperature bulbs - I think that one is 5000K and another is 2800K and the 3rd has them all on with a combo of 3800K.
I also have a desk lamp with a 9W 800 Lumens 5000k led bulb.
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digitaldog

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Re: Soft Proofing - Simulate Paper Col question
« Reply #3 on: April 05, 2022, 12:53:19 pm »

The first thing to establish is how to measure my viewing booth light to ensure I am viewing the prints under sufficient/correct illumination.
My viewing booth does not have a dimmer as yours does. It has 3 switches which activate 3 different col temperature bulbs - I think that one is 5000K and another is 2800K and the 3rd has them all on with a combo of 3800K.
I also have a desk lamp with a 9W 800 Lumens 5000k led bulb.
You don't necessarily have to measure the viewing system and if you could, it might not be useful. The calibration of the display targets to the display soft proof is trial and error. You do want to stick with one CCT (color temp) probably CCT 5000K which is a large range of possible colors so YMMV. That's the color of white, not the intensity and again, you'll have to experiment with calibration settings to get the match as shown in my screen capture earlier.
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FrankG

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Re: Soft Proofing - Simulate Paper Col question
« Reply #4 on: April 05, 2022, 02:27:43 pm »

This line that you wrote is really, in a nutshell, the answer to my original question. For that 'Thank you'.
When I view the prints from the lab, under suitable viewing conditions, they match my display only when the Simulate Paper Col box is checked -

"...The Simulate options provide a more 'accurate' (visually matching) soft proof because it takes paper white and black ink into account. It may look flatter and uglier (Jeff Schewe famously calls this option the "Make my image look like crap button") but reality can suck sometimes.
When you wish to compare the print next to the display for a match, you want that check box ON:"


With that box ON, I can make necessary adjustments to the image & more accurately preview the print (perhaps make a duplicate & have 2 windows open side by side, one to toggle the soft proofing on/off & the other with adjustment layers).

Would you say that having the "Make my image look like crap button" on  is true across the board for all or most papers (as long as the profile is good).
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digitaldog

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Re: Soft Proofing - Simulate Paper Col question
« Reply #5 on: April 05, 2022, 03:01:01 pm »

Would you say that having the "Make my image look like crap button" on  is true across the board for all or most papers (as long as the profile is good).
Yes because again, you're viewing a reduced contact ratio and when you see the soft proof update, it looks 'worse' than before. The trick is to position your cursor over the option (or in PS make a saved Customize Proof Setup) and toggle this ON without viewing it update. Let your eyes adjust away from viewing this for a second or two, then view the new preview. Also, view in Full-Screen view because the GUI in PS (whites) doesn't undergo this white simulation and your eye adapts to the whitest white. So you want to compare the soft proof to the print in this kind of viewing condition: Simulation ON, no other GUI elements.
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FrankG

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Re: Soft Proofing - Simulate Paper Col question
« Reply #6 on: April 05, 2022, 05:03:34 pm »

Thanks.
And could you say something about the separation of the White and Black simulation - 2 check boxes (Simulate Paper Col & Simulate Bl ink).
Why, in what kind of scenario, would you not want both On at the same time?
Perhaps so that you can make an adjustment for each individually/separately?
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digitaldog

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Re: Soft Proofing - Simulate Paper Col question
« Reply #7 on: April 05, 2022, 05:11:32 pm »

I don't see the need for separation but it exists. For soft proofing to a print, you want both.
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FrankG

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Re: Soft Proofing - Simulate Paper Col question
« Reply #8 on: April 05, 2022, 05:23:05 pm »

Thank you
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FrankG

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Re: Soft Proofing - Simulate Paper Col question
« Reply #9 on: April 05, 2022, 06:43:56 pm »

How would you typically go about bringing back the contrast that is lost with the Simulate  button ON?
A Curves or Levels Adj layer, or?
And, while the Soft Proof dialog is open, with the check/uncheck the preview button,  you can't access the Layers palette, so what is the best workflow to make the necessary adjustments?
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digitaldog

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Re: Soft Proofing - Simulate Paper Col question
« Reply #10 on: April 05, 2022, 06:50:27 pm »

How would you typically go about bringing back the contrast that is lost with the Simulate  button ON?
Mostly, you can't. Just as you can't use Vibrance or Saturation to boost out of gamut colors; they are out of gamut.
The display is an intermediary device you use to view your images as you prep them for print and when you soft proof, that's the reality. When you post to the web, while you can't control how others see your images, you can soft proof to a display (yours) and that's what you get.
You can make minor adjustments to some areas of the image under soft proofing to provide some changes based on the soft proof indeed. Here is where Lightroom shines as you can build a virtual copy with those edits. Or use Photoshop and adjustment layers for that print.
I don't see how turning on and off the soft proof help you considering the above. But if you want a 'before and after' preview, fine. But again, the print media has some limitations (as do displays) and there are areas where you can't fit round holes in square pegs.
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FrankG

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Re: Soft Proofing - Simulate Paper Col question
« Reply #11 on: April 05, 2022, 08:45:28 pm »

"You can make minor adjustments to some areas of the image under soft proofing to provide some changes based on the soft proof....use Photoshop and adjustment layers for that print. "
Yes, this is what I'm talking about. How to make these minor adjustments while the soft proof reference is open/available.

To recap, I was looking at print/s that were 'too dark' compared to my 'ideal' displayimage in Ps.
Then I used the softproof profile  & checked the Simulate box, now the print was a close match to the display image. Which tells me that the soft proof is good indication of how the image prints on that printer/ink/paper. It didn't/won't print like my ideal image because I didn't account for the paper white/black points.

Going forward, before outputting to print I would want to make adjustments to the file so that the soft proof image will look closer to how I would want the print to look when printed. Taking into account the unavoidable difference between the 'reality' of the backlit screen vs reflected light paper. And the subsequent loss of contrast etc. If I preview how it's going to turn out printed, the I can do something about it.
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FrankG

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Re: Soft Proofing - Simulate Paper Col question
« Reply #12 on: April 06, 2022, 10:10:18 am »

This thread, learning to use simulate paper col in soft proofing, has been a game changer for me. I opened my file as I'd like to see it with final edits, duplicated it & viewed the 2 side by side in full screen mode. Opened the soft proof & selected the profile & checked the boxes. Then started to adjust it with levels & curves until it matched as close as I could get (unfortunately I have to close the soft proof box before each adjustment & then reopen it). Printed it and voila, the print matches the image.
Thank you for that.
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MHMG

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Re: Soft Proofing - Simulate Paper Col question
« Reply #13 on: April 06, 2022, 11:50:19 am »


...The DR of the display is very often far exceeding the DR of the print. The Simulate options provide a more 'accurate' (visually matching) soft proof because it takes paper white and black ink into account. It may look flatter and uglier (Jeff Schewe famously calls this option the "Make my image look like crap button") but reality can suck sometimes.

...But this is all summed up here, so just watch:

Why are my prints too dark?
Why doesn’t my display match my prints?
A video update to a written piece on subject from 2013
In this 24 minute video, I'll cover:

Are your prints really too dark?
Display calibration and WYSIWYG
Proper print viewing conditions
Trouble shooting to get a match
Avoiding kludges that don't solve the problem


High resolution: http://digitaldog.net/files/Why_are_my_prints_too_dark.mp4
Low resolution: https://youtu.be/iS6sjZmxjY4


Andrew, your video tutorial offers the best advice I've seen yet on the whole "screen to print matching" methodology that printmakers need to master in order to get softproofing with the simulate paper color checkbox "on"  to work as advertised. I totally agree with you that all too many monitor calibration videos give calibration setpoint recipes but skip over the additional and very significant steps which need to be considered for the print viewing environment in order to make screen to print matching work as well as it should.

That said, I don't follow your logic of adjusting the dynamic range of your monitor (when it's possible) to more closely match the dynamic range of the chosen print media. My understanding is that this methodology is only useful when one does not intend to use the "simulate paper color" setting because simulate color paper is in fact already performing that compensation. A commercial photo lab operation might use a reduced monitor contrast range, for example, when running high volumes of RC gloss/luster type photo media so that staff does not have to contend with all nuances of invoking ICC profiles and softproofing yet still see a reasonably closer visual "match" to print output.

AFAIK, the vast majority if not all of today's display profiling apps map RGB 000 to L= 0 and RGB 255 to L=100, whether the monitor's dynamic range can achieve that or not, in effect a relcol with bpc type of scaling algorithm baked into the display profile. For a monitor with monitor white scaled to L*= 100, the monitor white to monitor black cd/m2 measured values must have a contrast range of approximately 1000:1 to generate an actual L*min of less than 1.0 for maximum black. That outcome also assumes no veiling flare reflection from the screen surface.  My NEC Spectraview natively reaches about 685:1 during calibration, thus a black L* min of approximately 1.4.  That's quite good but definitely not perfect. And to achieve even that, veiling flare has to be carefully controlled because even the best anti-reflection coatings still reflect about 1% of the light reaching the display panel surface. Thus, illumination on your monitor screen surface needs to be kept very low (i.e., less than 50 lux) otherwise your observable monitor black will climb higher than the calibration predicts.

To summarize, when the CMMs translate the print media L*min value to the soft proofed black visual appearance, the calculation is essentially based on the display profile mapped to the full 0-100 scale, again, whether the monitor/viewing environment has achieved that range or not. When the monitor calibration comes up short such that the viewable black is in reality significantly higher than L=0, then the displayed soft proof dark tones also end up a little on the lighter and lower contrast side of perfection. With today's high dynamic range flat panel displays, the typical display contrast error isn't all that big any more, but back in the CRT days with typical contrast range of 300:1 or so (achieved L*min approximately 3.0), I actually edited the paper profile's black point downward about 3-4 L* units  to compensate for the display profile's L* min error. Otherwise, the simulate paper color checkbox aka, the "make it look like crap" mode made the soft proof look even lower contrast than was deserved. The problem was traceable to the display profile's assumption of a perfect L* contrast range.  Modifying the ICC paper profile's inverse transform LUT was the only way to correct this error back then because profile editing software didn't exist to edit the display profile directly (and still doesn't to my knowledge).  I do recall a display profiling app made by Integrated Color Corp (now out of business) that could perform absolute scaling of the measured display LAB data as an option rather than recol w/bpc , but it was definitely an exception to the norm.

kind regards,
Mark
http://www.aardenburg-imaging.com
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digitaldog

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Re: Soft Proofing - Simulate Paper Col question
« Reply #14 on: April 06, 2022, 12:09:54 pm »

That said, I don't follow your logic of adjusting the dynamic range of your monitor (when it's possible) to more closely match the dynamic range of the chosen print media.
I get a better visual match.
https://www.xrite.com/service-support/contrast_ratio_in_i1profiler
« Last Edit: April 06, 2022, 12:17:51 pm by digitaldog »
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MHMG

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Re: Soft Proofing - Simulate Paper Col question
« Reply #15 on: April 06, 2022, 01:19:28 pm »

I get a better visual match.
https://www.xrite.com/service-support/contrast_ratio_in_i1profiler

Looks like the Xrite to Calibrate transition messed up that link. I get to a page that looks correct, but the link on that page Is no longer to your article.

cheers,
Mark

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digitaldog

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Re: Soft Proofing - Simulate Paper Col question
« Reply #16 on: April 06, 2022, 03:23:40 pm »

Looks like the Xrite to Calibrate transition messed up that link. I get to a page that looks correct, but the link on that page Is no longer to your article.

cheers,
Mark
Here's what it (used) to say:

Quote
When we calibrate a display, we specify what is called target calibration aim points. We inform the software that we want a certain White Point or Luminance (specified in cd/m2) of backlight intensity. These aim points are selected to produce a visual match between the display and the print viewed next to it. Therefore, the correct values are those that produce a visual match between these two items.

The new i1Profiler software provides another useful and important target calibration aimpoint: Contrast Ratio. To understand what this aim point does, and why it's so useful, consider what the contrast ratio describes. It's the range between the brightest white and darkest black. Contrast ratio is described using a scale such as 300:1. In this example, the brightest white is 300 times brighter than the darkest black. The higher the value, the greater the range between black and white. Here's the math for figuring out the contrast ratio of a display: Divide the white luminance by the black point. If you calibrated the luminance to 150cd/m2 luminance and a black point of .25, that would result in a 600:1 contrast ratio between the brightest white and the darkest black of this display.

Modern LCD displays are capable of producing very high contrast ratios. Manufacturers of such displays like to provide these high values as they are attractive for those playing video games or viewing video content. Yet these high values are not useful for those processing images and desiring a good soft proof between a display and a print. On a very glossy paper stock, using a very black ‘photo ink‘, this print may provide a 300:1 contrast ratio. Yet your display may have a contrast ratio of 800:1, 1000:1 or higher. If you soft proof in Photoshop and use the Simulate Paper Color and Ink Black checkboxes found in the Customize Proof Setup (Fig 1), Photoshop uses the ICC printer profile to adjust the print contrast ratio onto the display. The results are often disappointing because you see this very high contrast ratio display become dim as the proper contrast ratio for print viewing is simulated. It is far better to calibrate the display's contrast ratio rather than adjusting the ratio solely by using the paper and ink simulations in Photoshop. When using just Photoshop to do this simulation, only the image, not the rest of the user interface is adjusted which is far from ideal.

This is where i1profiler’s new contrast ratio target calibration aim point comes into play. If you know you will be viewing a glossy print and you wish to have a better match of the screen to the print, start with a target calibration of around 300:1 and compare the image being soft proofed on the calibrated display with the print properly illuminated next to that display. You may need to raise or lower that setting until you get a better match. The same is true for adjusting the white point and luminance! For matching to matt papers, a 200:1 contrast ratio may be a good starting point. It's not possible to provide an exact value! It takes trial and error to produce the best settings because everyone’s print viewing conditions, inks, papers, and displays are different. The idea is to control not only the target calibration aim points for white point and luminance for a print match but the contrast ratio too. When soft proofing in Photoshop, with the paper profile loaded and the two simulate checkboxes on, you should see a very good screen to print match. The key is the appropriate calibration target values, and setting the contrast ratio has a profound effect.
And previously by many years (2003), an article with the aid of Karl Lang for Sony Artisan:
http://digitaldog.net/files/BlackisBack.pdf
« Last Edit: April 06, 2022, 03:28:16 pm by digitaldog »
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John Hollenberg

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Re: Soft Proofing - Simulate Paper Col question
« Reply #17 on: April 06, 2022, 03:54:16 pm »

It is far better to calibrate the display's contrast ratio rather than adjusting the ratio solely by using the paper and ink simulations in Photoshop. When using just Photoshop to do this simulation, only the image, not the rest of the user interface is adjusted which is far from ideal.

This doesn't make sense to me (not saying it is wrong though).  If the simulate paper and ink does the job, why would it matter what happens with the rest of the interface?  Perhaps a more thorough explanation of why this is the case would be helpful.
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digitaldog

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Re: Soft Proofing - Simulate Paper Col question
« Reply #18 on: April 06, 2022, 04:56:18 pm »

This doesn't make sense to me (not saying it is wrong though).  If the simulate paper and ink does the job, why would it matter what happens with the rest of the interface? 
That part of the GUI doesn't undergo white simulation, so your eye adapts to that white, not the white in the image. It is why the "make my image look like crap" button makes your image look like crap just after you click on it  ;D (if you view it). See my suggestion about not doing so.
Now you don't have to work in full screen mode to view just the image.
« Last Edit: April 06, 2022, 04:59:56 pm by digitaldog »
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John Hollenberg

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Re: Soft Proofing - Simulate Paper Col question
« Reply #19 on: April 06, 2022, 06:20:59 pm »

That part of the GUI doesn't undergo white simulation, so your eye adapts to that white, not the white in the image.

Very helpful, thanks.  Do you suggest always working with lower contrast (not just when printing the image)?  The NEC Spectraview software I use also offers the ability to make a display profile with a lower contrast ratio.
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