Batman Light Levels

[Darin Steffl]

I just took a look at the Projectionist letter for Batman and it states the following. What does this mean?



To guarantee that the audience experience of this film is as intended, please ensure your theatres light levels are properly set to 14FL.

Screen Shot 2022-02-23 at 5.53.04 PM.png

[Frank Cox]

It means that the movie is shot very dark so if your screen is inadequately lighted the audience won't see much other than black.

[Darin Steffl]

So I'm still confused. Is 14FL referring to some light level on the projector itself or the ambient lighting in the auditorium? I've never seen this type of light measurement mentioned anywhere before. The only specs listed for projectors are lumens and contrast ratio.

How do I verify or calibrate our projector to achieve the recommended light level?

[Gordon McLeod]

Your installer should have set the light levels for you 14fl is the level of light reflected back from the screen by the projector

[Darin Steffl]

Your installer should have set the light levels for you 14fl is the level of light reflected back from the screen by the projector

Got it. I assume this was done when installed in 2012 but when we upgrade to a new laser projector in the future, I'll be sure to have our installer calibrate things.

Is there a range for this measurement that is good/bad? It says at least 14fl but is there an even better measure to shoot for?

[Frank Cox]

14fl is the standard so you should try to be as close to that as you can. Less than that is too dark and more than that leads to washed-out colours and gray looking blacks.

[Marco Giustini]

The director is simply reminding cinemas the cinema standards: a white field on the screen should read 14fL in a cinema - not just with Batman!

Unfortunately this standard is often overlooked for a number of reasons so the director thought to mention this hoping that someone would care a bit more!

I assume that a professionally installed cinema projector is always calibrated to DCI standards: DCI colour space AND 14fL in 2D. (Yes, I am a dreamer).

[Harold Hallikainen]

ST 431-1:2006 specifies center of screen luminance as 14 fL (48 cd/m^2) +/- 3 fL (10.2 cd/m^2) for theaters. Sides are to be 75% to 90% of the center luminance.

Harold

[Randy Stankey]

These kinds of letters were common, back in the day when I worked in the booth.

That and the infamous, "Fader on Seven" letters. Most often, they were form letters with, maybe, a quote from the director thrown in for good measure.

You'd find them tucked into just about every other film can. They were virtually boilerplate.

[Darin Steffl]

Too bad a fader level of 7.0 is too uncomfortable for anyone to watch. Most our movies have to be 5.5 to 6.0 or it's uncomfortably loud.

[Stefan Scholz]

If you can't play movies at 7.0, then have someone do a correct room tuning, which is anything, but 85dBC slow at 7.0.
The 14 fl (48 cd/m2 or nits) is the specified full white luminance reflected to the reference position in the center of the image. It should not be less than 80% in the corners.
This is valid for a projector with average (low) contrast. For High contrast projection, these machines really exist, a 22 to 30 fl is a fantastic way to enhance the perceived image, as then most humans are within color vision. 48 to 60 cd/m2 is the border to twilight vision with limited color reception. It was once chosen for economical reasons, well knowing the human vision mechanism. One of the reasons, why in many cases mid sized or small screen theatres looked better, than tose featuring a large movie screen.
If a movie is dark, then playing at less than 14 fl will make it night vision, without color and very limited sharpness reception. This is why they write: "at least 14 fl". I assume they expect to use the + 3 fl.
When comparing, remember, the brightness of the little indicator on your freezer is 600 cd/m2 or 170 fl.
It is not that difficult to measure the brightness. Most modern smartphone cameras can be used with an app to show brightness levels. Once the installer has finished his adjustment, you know the value his calibrated tool has read. Then adjust your phone to this reference, and for future controls, it is a good enough comparison value.

[Darin Steffl]

We are tuned properly to 85dbc at 7.0 and no one in their right mind could tolerate that in most features. If you can tolerate it, you've already started going deaf.

I test audio for every new release and skip to loud and quiet parts and while normal scenes with dialogue are fine at 7.0, anything louder hurts to listen to. I've read multiple posts that studios are increasing the volume because some theaters were turning the fader way down to like 4.0 or 4.5 where it's too quiet to hear most of the movie. So they compensated. This means 7.0 is now too loud for almost every movie.

We end up at 5.5 to 6.0 for most movies and sometimes 6.5 for some quiet movies.

[Harold Hallikainen]

The flicker fusion frequency is also luminance dependent. As luminance increases, flicker at the same flash rate becomes more visible.

[Marco Giustini]

We are tuned properly to 85dbc at 7.0 and no one in their right mind could tolerate that in most features. If you can tolerate it, you've already started going deaf.

.

I can, in a properly designed and tuned room. 85dBC is not everything, I'd say it's 25%. Room acoustic is another 25%. Speaker quality is another 25% and tuning and installation another 25%. (That said, a very poor job on any of those elements could make the result down to 0%).
Granted, some movies are unbearable at 7.0 but I'd say most are perfectly fine. Loud but fine.

On the brightness, let me also add that an average is always a good idea particularly on high gain screens (on flat frames and short throw - sigh!). A silver screen in that condition that reads 14fL on the hotspot will read 3-4fL in the corners.

[Jim Cassedy]

Darin S Said:

We are tuned properly to 85dbc at 7.0 and no one in their right
mind could tolerate that in most features.If you can tolerate it,
you've already started going deaf.

Well, I'm not qualified as an audiologist or psychiatrist, so I can't comment on or
confirm either of those assertions.
BUT_ - -
I've run dozens of screenings in both of Dolby's San Francisco corporate headquarters
screening rooms, which are probably close to being a couple of the most over engineered
and acoustically perfect environments on the planet. On more than one occasion, when
screening something at "7" for abuncha Dolby engineers and/or employees, I've been
asked to "turn it down a little". During one show a few years back, one of their upper-level
techguys came up into the control room, marched right past me, and without saying a word,
he went over to the audio rack and lowered the volume a notch or two.
(actually, I'm not surprised he didn't say anything. I don't believe Dolby employees are
allowed to utter the phrase "I think it's too loud"while on company property. It would be
akin to blasphemy)