Advice request on display calibration

[Panagiotis]

I am relatively new to display calibration and printing so I request your advice.

I watched Andrew Rodney's video "why are my prints too dark?" from which I understand that there is no magic number for display brightness.

I set up for a friend an Epson SC-P800. I wish to calibrate his new display (BenQ SW240) with my i1display pro.

My main concern is the level of brightness I will target for the calibration.

I am thinking to proceed like this (please correct me if I am wrong):

1. Adjust the level of lighting in the room at a comfortable and stable level.

2. Put a printed standard evaluation image under the viewing light (which is a desktop dimmable lamp fitted with a 5000K bulb) and adjust the level of lighting at a "correct" level and then remove the printed image and replace it with a plain paper of the same type.

3. Turn on the display, let it warm up, and adjust its brightness (and the white level as close as possible) at the same level as the paper under the viewing light.

4. Profile the display.

Any correction or advice is welcomed. Thanks.

[Ethan Hansen]

My suggestion is to err on the bright side for display luminance if necessary. We are most of the way through an evaluation of monitor calibration sensors and profiling applications (details coming out in a week or so). We measured sensor accuracy as well as calibration/profiling performance on a number of displays, including the BenQ SW271. Dropping white luminance below ~135 on the BenQ resulted in compressed shadow details with all but one profiling application -- not one made by X-Rite. The SW271 has a higher max brightness than does the SW240; whether this affects minimum calibrated brightness I can't say.

If your eyeball comparison of brightness levels indicates the need for a luminance level below 135 or thereabouts, pay particular attention to how shadow details are rendered on screen. It can be easier to train your eyes to compensate for minor differences in levels between print viewing and screen without running full on into "my prints are too dark" territory.

[digitaldog]

Many LCD displays can't natively hit low values for cd/m^2. In the old days, much below 100-120 cd/m^2 produced 'ugly' results as this was I believe adjusted outside the panel hardware. I was told back in 2011, the NEC 3090 could be targeted as low as 50cd/m2 without issue but I don't believe that's true for all modern LCD's.

[Ethan Hansen]

Many LCD displays can't natively hit low values for cd/m^2. In the old days, much below 100-120 cd/m^2 produced 'ugly' results as this was I believe adjusted outside the panel hardware. I was told back in 2011, the NEC 3090 could be targeted as low as 50cd/m2 without issue but I don't believe that's true for all modern LCD's.

NEC's PA-series happily run with low luminance levels. Eizo's best function well down to ~100 cd/M2. Other brands vary.

[faberryman]

NEC's PA-series happily run with low luminance levels. Eizo's best function well down to ~100 cd/M2. Other brands vary.

I'm don't what my cd/M2 number is. I just dialed down the brightness to match my prints. Seems to work.

[digitaldog]

I'm don't what my cd/M2 number is. I just dialed down the brightness to match my prints. Seems to work.

That's really the bottom line.

[Ethan Hansen]

That's really the bottom line.

Indeed it is ... up to a point. Just be aware that many of the budget photo-friendly displays - e.g. LG, BenQ, Viewsonic, some Dell, etc. - lose both accuracy, show compressed shadows and crossover artifacts, and have reduced gamut at lower luminance levels. Where that occurs depends on the screen in question. Adobe RGB gamut monitors are, at least in our limited sample set, more susceptible.

Make a pair of profiles, one with a white luminance calibration target of 160 cd/m2 (ISO 3664 P2 appraisal level) and another at 100 cd/m2. Compare both gamut size and black level resolution using an image such as this one on our site. If the performance is identical, rejoice. If not, consider your luminance target carefully.

[Panagiotis]

Indeed it is ... up to a point. Just be aware that many of the budget photo-friendly displays - e.g. LG, BenQ, Viewsonic, some Dell, etc. - lose both accuracy, show compressed shadows and crossover artifacts, and have reduced gamut at lower luminance levels. Where that occurs depends on the screen in question. Adobe RGB gamut monitors are, at least in our limited sample set, more susceptible.

Make a pair of profiles, one with a white luminance calibration target of 160 cd/m2 (ISO 3664 P2 appraisal level) and another at 100 cd/m2. Compare both gamut size and black level resolution using an image such as this one on our site. If the performance is identical, rejoice. If not, consider your luminance target carefully.

Thank you. I will do that. I was planning to use BenQ's own software (palette master element) to perform the calibration and profiling because I read that it's the only one that has access to display hardware.

[Jack Hogan]

Just be aware that many of the budget photo-friendly displays - e.g. LG, BenQ, Viewsonic, some Dell, etc. - lose both accuracy, show compressed shadows and crossover artifacts, and have reduced gamut at lower luminance levels. Where that occurs depends on the screen in question. Adobe RGB gamut monitors are, at least in our limited sample set, more susceptible.

Ethan, would you say that it is sufficient to have a monitor with good Contrast Stability for it not to suffer from such artifacts?

Jack
PS Love the line "Be warned, the file size is 100K so it may take a while to load" in your page

[alecdann]

I compare a blank sheet of the paper I'm using and a Tiff that's a white square and adjust the brightness and white point on the monitor to match the paper.  This approach is based on advice from Andrew (@Digitaldog).  For context, my viewing lights are Solux 3500k track lights positioned 7 feet above my viewing area. I get a reading of 700 lux with a Sekonic Litemaster Pro.  The monitor profiles I get using the visual comparison range in brightness from 128 cd/m2 for a Red River Ultra Pro Satin to 146 cd/m2 for Epson Legacy Baryta (a brighter paper).  I get good print to monitor matches this way.

[Doug Gray]

I compare a blank sheet of the paper I'm using and a Tiff that's a white square and adjust the brightness and white point on the monitor to match the paper.  This approach is based on advice from Andrew (@Digitaldog).  For context, my viewing lights are Solux 3500k track lights positioned 7 feet above my viewing area. I get a reading of 700 lux with a Sekonic Litemaster Pro.  The monitor profiles I get using the visual comparison range in brightness from 128 cd/m2 for a Red River Ultra Pro Satin to 146 cd/m2 for Epson Legacy Baryta (a brighter paper).  I get good print to monitor matches this way.

I'm curious as to what your monitor's white point is being profiled to in order to match 3500K lamps? What is the xy coordinates and CCT? I would think the monitor would appear quite yellowish.

[alecdann]

I'm curious as to what your monitor's white point is being profiled to in order to match 3500K lamps? What is the xy coordinates and CCT? I would think the monitor would appear quite yellowish.

For Red River Ultra Pro Satin (my proofing paper), the white point xy is .4290, .3937 and CCT is 3053k.
For Epson Legacy Baryta (my exhibition paper), the white point xy is .4287, .3948 and CCT is 3068k.


I notice the color shift if I change profiles (especially to one with a D50 or D65 illuminant), but as you know chromatic adaptation is a powerful thing. 

In my studio with lights in the 3500k range (I could read it with my i1Pro2 but from what I've heard, I'd have to spend several more thousand $$$ to get a spectrophotometer that can make a truly accurate reading), the monitor white point looks "normal".  If I changed my studio lights to 4700k (Solux's closest equivalent to d50) my monitor would look pretty yellow.

Human color perception is a curious thing.