Advice on Softproofing

[Robert Ardill]

Following on from my (no doubt irritating) questions about out-of-gamut processing, I would appreciate your advice on soft-proofing.

First of all, I think that the most important aspect of soft-proofing is to help avoid OOG problems.

But ... I think it can also useful to be able to give an idea of what the print will look like, given the paper color, black point etc., using different rendering intents (well, Perceptual and Relative Colorimetric for us photographers).

There seem to be two schools of thought here, as far as I can make out. 

The first seems to say that we should only use Black Point Compensation and Simulate Black Ink, leaving Simulate Paper Color out: the reason being, I think, that Simulate Paper Color in Photoshop only simulates D50 and doesn't match even 5000K viewing booths (can't say if this is true as I don't have a 5000K viewing booth . So this school of thought presumably doesn't believe in trying to match the monitor to the print.

The second seems to think that it is possible to match monitor to print, but for this it's necessary to use an expensive high-quality 5000K viewing booth with brightness controls etc (I almost bought one and feel relieved that I didn't .

I think the following (and as I'm not at all sure I'm right, I would very much appreciate your views):

• First of all, I think that most of the image processing should be done at 6500K and luminance of around 80cd/m2 with a wide-gamut monitor, if possible, with fairly subdued lighting in the room (or up the brightness to 100 or 120 if the light in the room is fairly bright).
• Then, before printing, view the image with Simulate Paper Color on, with the monitor image side-by-side with the illuminated paper that the image will be printed on
• Keeping the paper in the field of view, make any final adjustments before printing.

The reason (as far as I understand) why it's necessary to have the paper viewed alongside the monitor, is that the eye adjusts to the paper white automatically, whereas it doesn't to the monitor white.  Having the paper white beside the monitor fools the eye into adjusting to the monitor white.

The problem with this set-up is that it will only work if the lighting is bang-on D50 (which is impossible, I would think).  I use a Solux lamp which has a very good CRI and very little UV: however, this lamp is quite a bit warmer that 5000K (it's rated at 4700K, but in reality the bulb I have is closer to 4200K).  So my paper will look quite a bit warmer than the monitor white (with Simulate Paper color on).

As far as I can see there are four 'solutions' to this:

• Don't do it
• Use an expensive viewing booth and put up with the smallish differences between monitor and print
• Change your monitor white to match the paper white (interestingly, this is a method that Eizo promotes, so it can't be such a bad idea)
• Change the profile white to match the paper white

The last option seems insane, but I think it may be the best option.  I stumbled on it using ArgyllCMS as this software has an option to measure the paper white.  What it does with it is to put it into the 'wtpt' tag in the icc profile.  From what I’ve read in color.org and other places (for example http://www.normankoren.com/color_management_2.html) this tag is only used for Absolute Colorimetric.  Certainly, changing it to anything you want (I use IccXML) makes no difference to Relative and Perceptual.

However … Photoshop does use it (and so does Lightroom) to get the paper white in Simulate Paper White. That’s pretty crazy because some profiles use D50 as the white point and others use D65, but no doubt Adobe has its reasons.

Anyway, what this means is that the white point can easily be changed to the paper white for the viewing conditions.  What I do is to set up my Solux lamp to shine on a sheet of print paper beside my monitor and either get the paper white values manually (by using Lab in Photoshop to match the screen white to the paper white) or get them by using an i1Pro to measure the reflected paper white.  I don't touch my monitor settings - 6500K, 80cd/m2, native gamut etc.

I then put the XYZ values into the wtpt tag … and the monitor white now matches the paper white with Simulate Paper on.  But as I mentioned, it is necessary to have the illuminated paper beside the monitor when viewing the monitor image.

Exactly the same method can be used for different lighting.  So if we know that a customer is using Philips D65 fluorescents, then we can either set the ‘wtpt’ tag to 6500K, or go out and buy the same tube and get a correct value for the paper we will be using.

The method does seem to work in that prints very closely match the soft-proofed image on the monitor.  Here are a couple of examples:



and this shows that my set-up is somewhat work-in-progress ... and not entirely fire-proof!


So, I guess my question is not whether this works or not, because I know it does … but it’s whether it’s a really bad idea to do this (a bit like it may be a really bad idea to try to tweak OOG colors back into gamut using Hue/Saturation  ).  And also, are there any technical reasons why this should not be done?

If you've got this far, thanks for your patience!

Robert

[digitaldog]

Following on from my (no doubt irritating) questions about out-of-gamut processing, I would appreciate your advice on soft-proofing.
First of all, I think that the most important aspect of soft-proofing is to help avoid OOG problems.

I don't. It's to show me what the RGB numbers will look like on a print, a simulation of what the image will translate to on paper, not the display. OOG colors are a fact of life. And not one that's really a huge issue in most cases. Having an idea what a print will look like before you print it, a soft not hard print, helps avoid wasted media, time and money. Otherwise, simply forget soft proofing (it's far from prefect but far better than nothing), just make a test print or test strip.

[Robert Ardill]

Having an idea what a print will look like before you print it, a soft not hard print, helps avoid wasted media, time and money. Otherwise, simply forget soft proofing (it's far from prefect but far better than nothing), just make a test print or test strip.

Well, of course, Andrew, that's the whole reason I'm interested in soft-proofing  ... not to have to waste time and money with repeated prints to get the print right (whether this is due to OOG problems or to white point or black point problems, or whatever). 

But I'm not so sure I agree with you that it's far from perfect ... it isn't all the way there, but if you get the white balance and lighting right, and with good color management throughout, it's very close indeed, especially now with wide-gamut monitors.

What I meant about the OOG issue is that initially it's the important thing: soft-proofing helps to avoid what can be a major issue when you go from a very wide working space to a much narrower and less uniform destination space.  Once you have that beast tamed, then soft-proofing, as a very good simulation, should come into its own to get you the print you are aiming for.

What I'm not sure about is this:  if you are working at 6500K you have the gray-balance right and you should be able to adjust the image optimally; if you then move to a different white point this no longer applies (I presume); then there's the issue of the print being viewed in mostly unpredictable lighting conditions.  If we know exactly what lighting will be used then soft-proofing with that precise lighting should be really good ... but mostly we don't.

So what's the answer?

I don't know.  I usually try to find out from my customers what lighting they use or are likely to use and I aim for that.  On the other hand there's the eye's ability to adapt to different illuminants and paper colors, so it's not so straightforward  .

Robert

[digitaldog]

What I'm not sure about is this:  if you are working at 6500K you have the gray-balance right and you should be able to adjust the image optimally; if you then move to a different white point this no longer applies (I presume); then there's the issue of the print being viewed in mostly unpredictable lighting conditions.  If we know exactly what lighting will be used then soft-proofing with that precise lighting should be really good ... but mostly we don't.

So what's the answer?

Set the soft proof to show paper white simulation first of all. Calibrate the display with that in mind (the WP of the display that results in a visual match of the print next to the display).

More than one paper that would produce more than one WP calibration? Enter something like SpectraView which allows multiple display calibration aim points and loads the associated display profile on the fly.

[Robert Ardill]

Set the soft proof to show paper white simulation first of all. Calibrate the display with that in mind (the WP of the display that results in a visual match of the print next to the display).

I entirely agree that the display and paper whites should be matched side by side - otherwise the eye will not adapt to the display white.  However I think it's better to alter the paper profile white point, as I tried to explain above, for two reasons: a) it's simpler, b) soft-proofing then automatically gets the correct white point without having to change anything on the monitor (or anywhere else).

More than one paper that would produce more than one WP calibration? Enter something like SpectraView which allows multiple display calibration aim points and loads the associated display profile on the fly.

I was really talking about more than one illuminant, rather than more than one paper.  It's fine getting soft-proofing for a particular paper with a particular illuminant (say Canson Platine with Solux 4700K lamp) ... but a print made like this may not look so good under a fluorescent with spikes all over the place.  Papers with optical brighteners are even worse (unfortunately for me I have to use one for some of my prints).

Again, there's no reason why one shouldn't have a different profile with different white points for each of these lighting conditions - it just gets to be a pain.  In general I do try to find out from my customers what sort of lighting they have ... but apart from galleries the best most of them can say is that 'I have neon tubes in the ceiling' or something like that .

Robert

[Tim Lookingbill]

I actually find Soft Proofing useful even though I don't print on fine art 100% rag non-glossy paper, just 8x10's off my $50 Epson All In One using Epson's Ultra Premium Glossy.

But I don't implement it the same as others since I print using "Printer Manages Color". What I do is download one of Epson's wide format 7800 series printer profiles of similar paper and check my saturation levels by noticing any luminance hits with Relative Intent setting. That's my OOG "posterized" warning sign instead of relying on Photoshop's OOG.

I then print a small strip of the area in question as Andrew suggests. Most of the time even with a luminance hit Soft Proofing this way my Epson still prints the OOG portions as it appears on screen. Most of the time it's hue shifts, not flat blobs of blown detail I have to correct for which I use ACR's HSL panel to fix. I don't like using any of Photoshop's color editing tools when I have something more easier and immediate with the least noise induced artifacts using the HSL panel in the Raw converter.

Nice setup by the way. Just hope your Solux lamp's power converter doesn't crap out like it did on mine.

[Tim Lookingbill]

What I'm not sure about is this:  if you are working at 6500K you have the gray-balance right and you should be able to adjust the image optimally; if you then move to a different white point this no longer applies (I presume); then there's the issue of the print being viewed in mostly unpredictable lighting conditions.  If we know exactly what lighting will be used then soft-proofing with that precise lighting should be really good ... but mostly we don't.

So what's the answer?

I don't know.  I usually try to find out from my customers what lighting they use or are likely to use and I aim for that.  On the other hand there's the eye's ability to adapt to different illuminants and paper colors, so it's not so straightforward  .

Robert

I won't be a customer of yours for obvious reasons but the thread I started...

http://www.luminous-landscape.com/forum/index.php?topic=89689.0

...was my answer to my lighting situation for my own personal prints and may answer some your questions you have about how your customers are going to be viewing your prints. Expect the worse is all I can say but I'ld suggest you tell them they'll need a full spectrum light similar to the Solux to see the same results at point of purchase online and in your studio.

Regarding that link to my print lighting dilemma the orange flower was OOG for my Epson and was rendering it with too much magenta so I had to make it far too yellowish to compensate. Soft Proofing using the Epson 7800 series profile (assuming it has a much wider color gamut) didn't show this hue shift which I think most Soft Proofing won't according to what I've seen of its use even with custom printer profiles in these forums, but I can't be sure.

[Robert Ardill]

I'll explain the steps I take in detail to soft-proof.  I would be very interested if one of you would try this out.

• With the illuminated paper white beside the monitor, I create a new document in Photoshop and (in full-screen mode) I adjust the Lab values so that I get a visual match to the paper white.
• I convert these Lab values to XYZ using http://www.brucelindbloom.com/index.html?WorkingSpaceInfo.html. The Ref. White must be D50. This gives me the XYZ values for the paper white.
• I convert the paper profile to xml using IccXML: http://sourceforge.net/projects/iccxml/
• I copy and paste the XYZ values from Bruce Lindbloom's calculator into the 'wtpt' tag in the xml version of the paper profile
• I convert the xml version of the profile back to icc, again using IccXML
• The modified profile can now be used to soft-proof: Simulate Paper will give the correct paper white for the lighting conditions used.

It would be relatively easy to write a program to automate this process - but even manually it only takes a few minutes.

I don't really understand what Photoshop is doing, to be honest.  Perhaps someone does?  My guess is that it does something like this for softproofing:

• First of all, it converts the image to the destination profile and back again. This adjusts the OOG colors, black point etc.
• Then it re-maps the image to the white point in the 'wtpt' tag using ... the Bradford transform, perhaps?? http://en.wikipedia.org/wiki/White_point

Be interesting to know.

Robert

[Tim Lookingbill]

I'ld rather print than go through all that trouble, Robert.

I paid for the technology to do its job which is pretty decent considering the level of complexity working under the hood and accept its limits and move on.

[Robert Ardill]

I'ld rather print than go through all that trouble, Robert.

I paid for the technology to do its job which is pretty decent considering the level of complexity working under the hood and accept its limits and move on.

Well, the thing is, Tim, that this IS using the technology (or at least attempting to .  However ... I accept that setting up a color-managed workflow to that extent won't float everyone's boat.  But for those who want to fine-tune things so that what you see is what you get (or as close as possible) ... well, then, as a minimum, you do have to calibrate and profile your monitor and printer.

I think you are using a profile made for one printer to give you an idea of OOG problems on another printer ... well, that will probably sort of work.  Then I assume you're printing using sRGB with the printer managing the color - which is fine.  But if you want to make the best of your printer then you would need to profile it for its full gamut and not restrict it to sRGB. Still, if you're happy with the way you're doing things then that's great!

Robert

[digitaldog]

• With the illuminated paper white beside the monitor, I create a new document in Photoshop and (in full-screen mode) I adjust the Lab values so that I get a visual match to the paper white.

And I do this building the display profile (SpectraView allows me to produce visually that white, builds all that into the calibration and profile).

I copy and paste the XYZ values from Bruce Lindbloom's calculator into the 'wtpt' tag in the xml version of the paper profile

And this updates the AtoB, BtoA or both tabes? I'm not sure this is a good route to go down but I need a lot more coffee and some time to think about it. I'm thinking this should be done on the preview/display side, not in the output profile but again, what tables are affected is kind of critical here.

[Robert Ardill]

And I do this building the display profile (SpectraView allows me to produce visually that white, builds all that into the calibration and profile). And this updates the

Yes, that's an alternative way of doing it. ColorNavigator from Eizo also has a very nice feature to allow visual adjustment of the monitor profile to match the print white.  Here is their recommendation: http://www.eizo.com/global/library/management/matching/.

It's a bit more awkward to use (with the Eizo at any rate) because there is a need to switch profile when soft-proofing. It's only a click of a button, but still.  If you modify the print profile you can use softproofing with or without Simulate Paper Color, but when you click on Simulate Paper Color you get the right white without having to do anything at all.  So you can stay at 6500K all the way through.  All I can say is that it works really well ... you should give it a go, it's not hard to do.

I don't know to what extent this matters, but generally the recommendation for LCDs is to stay at 6500K and not go down to 5000K or below (quite a bit below with a Solux lamp) because of possible banding issues.

AtoB, BtoA or both tabes? I'm not sure this is a good route to go down but I need a lot more coffee and some time to think about it. I'm thinking this should be done on the preview/display side, not in the output profile but again, what tables are affected is kind of critical here.

Well the only change is to the wtpt tag.  However ... I have no idea how Adobe implements the white point transform for soft-proofing.  All I can say is that there's certainly no change in the working space to printer direction.

The mechanism does appear to be part of the Adobe soft-proofing though.  It would be very interesting to find out exactly how the soft-proofing is implemented (would you have any contacts in Adobe who could tell us?).

Robert

[Tim Lookingbill]

I think you are using a profile made for one printer to give you an idea of OOG problems on another printer ... well, that will probably sort of work.  Then I assume you're printing using sRGB with the printer managing the color - which is fine.  But if you want to make the best of your printer then you would need to profile it for its full gamut and not restrict it to sRGB. Still, if you're happy with the way you're doing things then that's great!

Robert

You can't assume I'm printing in sRGB not even with my $50 Epson.

I don't believe anyone can know exactly what color space my Epson receives data seeing that my images data stays in ProPhotoRGB and gets passed to the printer driver using "Printer Manages Color" with a conversion (I'm assuming) through Mac OS Quartz driven data handling as mentioned often in discussions here on resolution upsampling by the OS printer pipeline on higher end Epsons.

Again since I can't know what's going on under the hood to make this happen I'm having to assume if the OS is manipulating resolution this way then it must be providing some kind of color description conversion for my dinky Epson to give me pretty darn close color matches with no clipped detail since the data is ProPhotoRGB sourced. It used to be many years back if I sent wide gamut encoded data using "Printer Manages Color" the results would be quite desaturated and butt ugly. No more.

All I know is what I thought would be way out of gamut color saturation levels (255 in sRGB) for a printer to reproduce viewed on my sRGB display and which used to print as flat blobs of posterized color, now prints just fine. No one has been able to explain how that happens under the hood. Even Walgreen's Fuji Frontier drylabs are reproducing detailed, saturated color (in sRGB space-255RGB clipped data) that used to print as flat blobs of dull color on a Noritsu about 8 years ago.

So from this observation I don't think it's possible or even beneficial to control everything in the screen to print pipeline at the levels of complexity and time devoted you're proposing. IMO it appears you're investing 90% of work time and effort to get back maybe 5% extra bit of precision in color matching no one is ever going to see in a print, not even your customers.

[Robert Ardill]

So from this observation I don't think it's possible or even beneficial to control everything in the screen to print pipeline at the levels of complexity and time devoted you're proposing. IMO it appears you're investing 90% of work time and effort to get back maybe 5% extra bit of precision in color matching no one is ever going to see in a print, not even your customers.

Hey Tim,

Well, I have to say I don't agree with you there .  For sure I've put in a fair amount of time and effort into this, but there are many paybacks.  The main one, of course, is that my printing has improved significantly, and it's now very rare that I get a print that is different to what I intended. Before investing in all of this, my first print was almost always wrong in some way or other, and I would have to reprint, maybe several times: very expensive and time-consuming!!  The other big benefit is less easy to quantify, but it's down to understanding what's happening.  So, for example, I do now understand the whole black-point, dMax, gamma thing and as a result I don't get clipping in the shadows any more (unless I want it): this may seem a small thing, but I think it makes a big difference to a print because the shadow detail gives lightness and body to the print.

But I'm a perfectionist and I like to know what's under the hood ... fortunately the world can accommodate all of us .

Robert

[Tim Lookingbill]

Hey Tim,

Well, I have to say I don't agree with you there .  For sure I've put in a fair amount of time and effort into this, but there are many paybacks.  The main one, of course, is that my printing has improved significantly, and it's now very rare that I get a print that is different to what I intended. Before investing in all of this, my first print was almost always wrong in some way or other, and I would have to reprint, maybe several times: very expensive and time-consuming!!  The other big benefit is less easy to quantify, but it's down to understanding what's happening.  So, for example, I do now understand the whole black-point, dMax, gamma thing and as a result I don't get clipping in the shadows any more (unless I want it): this may seem a small thing, but I think it makes a big difference to a print because the shadow detail gives lightness and body to the print.

But I'm a perfectionist and I like to know what's under the hood ... fortunately the world can accommodate all of us .

Robert

I'm going to have to assume you're printing on non-OEM printer paper and most likely non-glossy which would probably require extra effort for predictability.

I only print with OEM Epson glossy paper and ink so I don't need to be that perfect. But I still have to say there is way too many mysteries involved with my setup that doesn't make a lot of sense with regard to color gamut mismatches between screen and printer reproduction capabilities.

Below is my Soft Proofing and OOG mystery printing business cards without going to your lengths of print match predictability. Basically the results shown below are not suppose to happen according to what the technology says because that orange flower has clipped data in sRGB mainly in the greens and oranges but I still get a print match. I'm having to assume my $50 Epson has the same color gamut size as the more expensive Epson 7880 which doesn't make any sense.

[Geraldo Garcia]

Basically the results shown below are not suppose to happen according to what the technology says because that orange flower has clipped data in sRGB mainly in the greens and oranges but I still get a print match.

Remember that Gamut warning do not tell you how much out of gamut the colour is. It may be 0,00001 DeltaE or 100 DeltaE. In your case it is probably so close that it doesn't matter. Besides, if you use perceptual rendering intent it tries to preserve tonal differences while remapping colours to match the gamut, theoretically preserving detail in OOG areas of the same colour.   

[Lundberg02]

You can't assume I'm printing in sRGB not even with my $50 Epson.

I don't believe anyone can know exactly what color space my Epson receives data seeing that my images data stays in ProPhotoRGB and gets passed to the printer driver using "Printer Manages Color" with a conversion (I'm assuming) through Mac OS Quartz driven data handling as mentioned often in discussions here on resolution upsampling by the OS printer pipeline on higher end Epsons. >>

I do the same thing with my similar six color Epson. I print from ProPhoto using Photoshop manages colors and get just about the same result if I use printer manages. If I use the correct printer and paper profiles, I get a very good match to my screen plus better blues and reds. I'll be using wide gamut soon and we'll see if I have to adjust anything. I can do a hard proof with a few clicks and be confident that people with the right skills have worked very hard to produce that print.

[Robert Ardill]

I do the same thing with my similar six color Epson. I print from ProPhoto using Photoshop manages colors and get just about the same result if I use printer manages. If I use the correct printer and paper profiles, I get a very good match to my screen plus better blues and reds. I'll be using wide gamut soon and we'll see if I have to adjust anything. I can do a hard proof with a few clicks and be confident that people with the right skills have worked very hard to produce that print.

Well there's nothing wrong with Printer Manages Color as opposed to Photoshop Manages Color as long as you are using the right profiles for the paper.  All that happens is that the working space data is mapped to the printer/paper output by the printer driver in the first case, and by Photoshop in the second.  It could well be that your printer driver does a better job of this than Photoshop.  The printer driver will normally use the Apple ColorSync or Microsoft ICM engine whereas Photoshop uses Adobe ACE ... and maybe these do a better job in some cases.  A comparison would be interesting.

Unless you use light near 5000K in your work environment, I don't see how your monitor image can match your print - side by side - because the white points will be different (unless you've adjusted your monitor to your working illumination).  What does work quite well is not to view the two side-by-side, allowing the eye some time between looking at the print then at the monitor image - that way the eye adapts to the white point of each and compensates automatically (pretty amazing huh?).

Robert

[Tim Lookingbill]

Remember that Gamut warning do not tell you how much out of gamut the colour is. It may be 0,00001 DeltaE or 100 DeltaE. In your case it is probably so close that it doesn't matter. Besides, if you use perceptual rendering intent it tries to preserve tonal differences while remapping colours to match the gamut, theoretically preserving detail in OOG areas of the same colour.    

I'm aware of that. That wasn't the point I was making.

I'm now of the school of thought that we have put way too much faith and developed unreasonable expectations in the technology because we marvel at what it can do without our help but can only offer speculative answers to explain why.

You're not a color scientist. You didn't make any of the color reproduction devices. You don't know a lick about programming a computer to know when something works or doesn't with regard to controlling color processes. We tend to inject meaning and intent behind the process of capturing an image digitally and seeing it as some type of controllable object when it really is just software manipulating it all without our knowledge.

And we seem to be under the same misconception and assume by our ability to control this self imposed objectification of the technology consistently that it's designed to function that way. We assume when we fiddle with a knob here and tweak and measure some piece of analytical software in order to characterize the level of consistency we fool ourselves into thinking that when it isn't consistent that WE are the ones doing it wrong or not understanding correctly or the technology is broke and thus make ourselves go down a time wasting troubleshooting rabbit hole instead of just making it work by other easier methods.

[Robert Ardill]

I'm aware of that. That wasn't the point I was making.

I'm now of the school of thought that we have put way too much faith and developed unreasonable expectations in the technology because we marvel at what it can do without our help but can only offer speculative answers to explain why.

You're not a color scientist. You didn't make any of the color reproduction devices. You don't know a lick about programming a computer to know when something works or doesn't with regard to controlling color processes. We tend to inject meaning and intent behind the process of capturing an image digitally and seeing it as some type of controllable object when it really is just software manipulating it all without our knowledge.

And we seem to be under the same misconception and assume by our ability to control this self imposed objectification of the technology consistently that it's designed to function that way. We assume when we fiddle with a knob here and tweak and measure some piece of analytical software in order to characterize the level of consistency we fool ourselves into thinking that when it isn't consistent that WE are the ones doing it wrong or not understanding correctly or the technology is broke and thus make ourselves go down a time wasting troubleshooting rabbit hole instead of just making it work by other easier methods.

Hi Tim,

I know this answer isn't directed at me, but I suspect you probably feel the same about my comments and questions, so I might venture a thought or two.  I'm an electronic engineer with a post-graduate in computer science and I've spent most of my working life in software and hardware development, mostly in telecommunications but also in process control and instrumentation.  So I have a reasonable background in maths and there are similarities between the sort of things that CMMs and profiles attempt and the sort of work that I've been involved in (especially in signal processing). 

However ... I've only been looking at color management fairly recently (a few months), even though I've been a professional photographer for ten years now and have been doing my own printing for a while longer than that.  There is a huge amount to it and it's very confusing, especially because software vendors like Adobe don't tell you what they're doing when they do something like turning Simulate Paper Color on in soft-proofing.  So a lot of the time it's down to guess-work, and doing tests to see if the guess-work seems to be right or wrong ... and asking others who've been there before for their help.

You seem to feel that this is just a waste of time and that one's conclusions are quite likely to do more harm than good. But if you don't understand your tools you are equally likely to end up with a lesser product.  For example, I've just watched Andrew Rodney's absolutely excellent Youtube video on DNG Camera Profiling ... and he reduces all the confusion around by explaining very clearly that what the profiling does is effectively to condition the raw image to the spectrum of the illuminant; and furthermore that the shape of daylight spectra does not change fundamentally with different times of day or cloud conditions or geographical location.  So, as with a scalpel, he has cut down the muddle of potentially hundreds of profiles, just for outdoor photography, to just one profile. That's what understanding does.

So how can you know, before embarking on an attempt to understand things like soft-proofing, profiles, rendering intents, CMMs, illuminants, inks, papers, not to mention the eye and the psychology of vision etc., what you are going to find out?  All that I can say is that I may irritate people with my questions (and I am sorry for that!), but I have learnt a huge amount and it's been well worth the effort and frustration.

Having said that, I do agree that experience and good judgement, and seeing the bigger picture, and not getting bogged down in detail to the detriment of the end result ... is equally important, if not more so.  There really isn't much point in having a brilliantly color-managed system if the basic capture is badly framed, taken in flat light, over-exposed, badly developed ... and so on.  But if that stuff is OK (always room for improvement!), then why not make the best of the technology, to the best of one's ability?

Or perhaps I've misunderstood your points?

Robert