Determining viewing light brightness for print

[digitaldog]

Well, it is a problem for some.

Some have lots of problems easily solved.

So, he painted near a very large window by daylight and was consistently frustrated by his inability to find an artificial light source that would emulate natural light.

That IS difficult because man made lighting isn't anywhere as desirable than sunlight! Thankfully we have Solux bulbs, about the best man made illuminant to mimic daylight.
Do examine:
http://solux.net/cgi-bin/tlistore/infopages/index.html
They do have issues (heat for one), but just look at the spectrum!

Yes, and it appears that the rational light level commonly found in the real world is around 500 lux (incident reading).

And when you move a print into rational light level commonly found in the real world is around 400 or 600 lux etc, it's fine; your eye adapts to that (and more!).

I have read The Negative, The Print and many of his other writings.

Then tell me which page(s) Adams complains about print viewing conditions described here and his 'solution'?

It's hardly overcomplicating things to check that the light in the gallery is at a reasonable level.

That's my point, it isn't complicated.
How many here have photographic prints hanging in their homes? I have many dozen and no issues. I didn't need a light meter to evaluate now to light my photographic prints or otherwise. It's not at all complicated.
Matching a display to a print NEXT to the display, for brightness, contrast and WP is more complicated, but absolutely doable. 

There seems to be this assumption by the general public that artist are just a these untamed, mysterious creatures, that simply operate on emotion and technique never crosses their mind.

"I never guess/assume. It is a shocking habit -- destructive to the logical faculty." -Sir Arthur Conan Doyle
I don't deal well with assumptions. Of the 'general public' to boot. 

We're talking about a commonly found level of illumination found in the real world where your prints are going to be seen.

That and more! And it's not complicated and we are lucky to have adaption of human vision.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4742349/
And then it's fun to go into issues and optical illusions when viewing anything.
How to control:

Square A and B are the same color of gray.

But if your average exhibit space, office, store etc across the entire planet is illuminated at around 500 lux, then it is not such a crazy idea to assume that this may be a good baseline level of illumination to review your prints under.

Assume anything you wish. In the end, most of this is a search for a solution in which a problem doesn't exist.

[digitaldog]

So, while I am not a color scientist, I am not completely ignorant about what we are talking about here.

Frans is a bit new to both, best to ignore him.
Here is just one (for Frans short) example of his misunderstanding of basic color such as CCT:
https://www.photo.net/discuss/threads/do-solux-bulbs-meet-color-temp-specs.482331/#post-5072451
Guy has zero tools to evaluate anything to do with colorimetry as the paper trails on various photo cites can prove.
He's hardly the person anyone needs to listen to in terms of learning about color constancy or "Determining viewing light brightness for prints."

[Harry Lime]

Some have lots of problems easily solved. That IS difficult because man made lighting isn't anywhere as desirable than sunlight! Thankfully we have Solux bulbs, about the best man made illuminant to mimic daylight.
Do examine:
http://solux.net/cgi-bin/tlistore/infopages/index.html
They do have issues (heat for one), but just look at the spectrum!

Exactly.

We have had to deal with the same problem in film production, with the arrival of LED lighting. The early LED lamps had huge gaps or nasty spikes in their spectral output compared to traditional light sources like tungsten. The more recent LED lights are much improved and actually useable, but to this day many cinematographers still feel that tungsten is king.

Here is another example. Kinoflo florescent lighting has always been a problem due to the nasty green spike. Great for green screens or if you are shooting Seven (David Fincher), but not so great if you don't want your leading lady to look like she has jaundice.

I just spent three years working for a major tech company in silicone valley on this very problem. It's interesting how it wasn't a problem, until it became a problem, due to the arrival of new technology.

And when you move a print into rational light level commonly found in the real world is around 400 or 600 lux etc, it's fine; your eye adapts to that (and more!).

Exactly.

Then tell me which page(s) Adams complains about print viewing conditions described here and his 'solution'?

Don't be ridiculous. I'm a 50 year old man and am not going to play a silly game like that.

How many here have photographic prints hanging in their homes? I have many dozen and no issues. I didn't need a light meter to evaluate now to light my photographic prints or otherwise. It's not at all complicated.

I have artwork hanging in my dwelling. I do know that some of those prints appear to be darker than they were intended to be, because the lighting in that part of the house is pretty dim. Does it bother me? It's not the end of the world, but I may do something about it some day.

But I have been to the house of a serious collector. He had track lighting installed. Now, that I think about it the light level on his artwork looked an awful lot like what you see in an exhibit space. I would not be shocked if it turned out to be 500 lux like in a museum...

Matching a display to a print NEXT to the display, for brightness, contrast and WP is more complicated, but absolutely doable. 

Of course.

"I never guess/assume. It is a shocking habit -- destructive to the logical faculty." -Sir Arthur Conan Doyle
I don't deal well with assumptions. Of the 'general public' to boot.  ;)That and more! And it's not complicated and we are lucky to have adaption of human vision.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4742349/
And then it's fun to go into issues and optical illusions when viewing anything.
How to control:

Square A and B are the same color of gray. Assume anything you wish. In the end, most of this is a search for a solution in which a problem doesn't exist.

Well, we can go around and around on this subject for an infinite amount of time. There are an endless set of variables involved in this that no one can control. But like you said, there is no point in overcomplicating this.

So, here is my plan.

The average illumination level for an exhibit space, office, store and many other public spaces is around 500 lux (incident reading).
A GTI booth used for print evaluation is about 500 lux.
In my personal shooting experience 500 lux is a very common level of illumination for anything from a museum to an office or a store.

Therefore I am going to go for 500 lux @ 5000k (incident reading) as a good real world average for print review. This way I know that my print stands a fighting chance of appearing as I intended it be seen, in a high percentage of locations in the real world.

Fortunately for me that level of illumination also happens to match my display nearly perfectly with the recommended monitor calibration settings by Inkjetmall for their Piezo Pro system.



 

[digitaldog]

Don't be ridiculous. I'm a 50 year old man and am not going to play a silly game like that.

Here's the exact question I asked you don't wish to answer:

Please dig up some text from Adam's discussing this issue for him too, if such an issue ever existed.

Adams either reported issues you say should be reported or he didn't. I'm simply asking for a clear answer. You now know I don't like to assume. But one could assume Adams never had any such issues.

I do know that some of those prints appear to be darker than they were intended to be, because the lighting in that part of the house is pretty dim

That's your doing. 
If you turn off all the lights at night, it's going to be very dark.

There are an endless set of variables involved in this that no one can control.

Control those you can, move on, let your eye adapt to reasonable lighting of prints. Simple.

The average illumination level for an exhibit space, office, store and many other public spaces is around 500 lux (incident reading).
A GTI booth used for print evaluation is about 500 lux.
In my personal shooting experience 500 lux is a very common level of illumination for anything from a museum to an office or a store.

So again, there's far more to all this than simply lus. There's color temp of the bulbs. There's the spectrum of the illuminant we've just talked about. There's the surround (how would Adams print look surrounding an orange wall?). You can't control that.
GTI booths (which I own) have a pretty ugly spectrum. Not ideal if you ever print using papers with OBAs:
http://digitaldog.net/files/24TroubleWithFWAs.pdf
Since you say you're new to printing, that's an issue to examine.

Fortunately for me that level of illumination also happens to match my display nearly perfectly with the recommended monitor calibration settings by Inkjetmall for their Piezo Pro system.

And White Point, contrast ratio? OF ALL PAPERS?
Having a true color reference display (smart display), you can calibrate that display for a matte paper with a 150:1 contrast ratio and a WP that can vary due to paper white, then switch on the fly to a calibration (and profile) that calibrates for a glossy paper, with a 250:1 ratio and a vastly different paper white. Now that's soft proofing!
http://blog.xritephoto.com/2011/07/x-rite-i1display-pro-advanced-features-contrast-ratio-with-coloratti-andrew-rodney/

[Doug Gray]

Not ideal if you ever print using papers with OBAs:
http://digitaldog.net/files/24TroubleWithFWAs.pdf

Totally agree. OBAS are a PITA. Most all indoor lighting doesn't have anywhere near M1 levels of uV and even profiles made with M0 rarely match viewing conditions. I also stick with M2 and OBA free paper.  BTW, while unrelated to OBAs, nice example of metamers and metameric failure.

Since you say you're new to printing, that's an issue to examine. And White Point, contrast ratio? OF ALL PAPERS?
Having a true color reference display (smart display), you can calibrate that display for a matte paper with a 150:1 contrast ratio and a WP that can vary due to paper white, then switch on the fly to a calibration (and profile) that calibrates for a glossy paper, with a 250:1 ratio and a vastly different paper white. Now that's soft proofing!
http://blog.xritephoto.com/2011/07/x-rite-i1display-pro-advanced-features-contrast-ratio-with-coloratti-andrew-rodney/

I'm curious as to why not just set chromaticity coords. and luminance against a a profiled (M2) paper to match? Then just selecting show black ink and paper white softproofing takes care of all the dynamic range and paper white differences without changing the monitor setting. Is it just to avoid selecting soft proof on the display? It's work to tweak the display for each paper when you can just let the icc profile do the work.

OTOH, Using icc profiles to soft proof does require that the profiles be high quality and consistent and many OEM profiles aren't. Some even incorrectly encode stuff like the dynamic range so tweaking the monitor settings for those papers is the only way out other than getting or making custom profiles.

[JRSmit]

With LED lighting the OBA discrepantie worsened in my experience. A hear ago I gave a workshop for photographers on the choice of papers for Fine Art prints of their work for an upcoming exhibition. In the lighting (LED)  used in the space you could not see whether a paper had OBA or not. So we went outside, it was about 3-4 hours  after sunset, so dark, and yet the differences in the paper whites were very visible. The ones containing OBA standing out.

[Doug Gray]

With LED lighting the OBA discrepantie worsened in my experience. A hear ago I gave a workshop for photographers on the choice of papers for Fine Art prints of their work for an upcoming exhibition. In the lighting (LED)  used in the space you could not see whether a paper had OBA or not. So we went outside, it was about 3-4 hours  after sunset, so dark, and yet the differences in the paper whites were very visible. The ones containing OBA standing out.

Yeah, that's completely normal. Outside of some specialty LEDs, they contain little uV. So if you should use M2 (uV cut) profiles if viewed under LEDs.

And there's a reason the newer (cheaper) spectros like ColorMunki and Studio make profiles that are only M2. They use LEDs that have virtually no uV. Incandescent and daylight through a window have some, but not much, uV. And even M0 can overstate the uV content. M0 is typically measured with an incandescent illuminant in a quartz bulb to allow uV. Few incandescent lamps use quartz and their uV content is less than that assumed by M0. LEDs in common use have even less uV.

M1 is the same as direct sunlight. This is appropriate when using papers with a lot of OBAs and viewing outdoors in daylight.