These are not THX Specifications, these are TAP Recommended Guidelines. Brad just posted them in the "Instructional Documents" in the Manual section, here at Film-Tech. Please, check it out and let me know what you think.

This is part of TAP's effort to raise the bar for overall quality presentations worldwide... so if you feel the TAP Guidelines are useless, let me know. Positive feedback is always welcome, especially following posts by Evans Crisswell...

But seriously, I welcome your constructive criticism... so hit me, baby!

Yours,
Ted Costas
Manager, THX Theatre Alignment Program

I don't mean to come across as negative when I talk about THX. I will check out the new document. However, most of my negative observations about THX do not concern specifications or recommended practices. It's about execution of them. Remember that old 50's song with naughty lyrics "It ain't the meat it's the motion". Well, that's the way it is with THX. Even with perfect specifications and recommended practices, it's the quality control and the making sure that theatres continue to remain up to specification and actually carry out the recommended practices that is important.

I'm about to download the document and check it out now.

Evans A Criswell

 

For digital screen illumination, I see that 6500K +/- 300K is the specification, which is quite "bluish". I assume this may be lowered, depending upon the final SMPTE standard?

Could you please explain the digital image focus resolution specifications? Is 25 lp/mm (line pairs per millimetre) specified on the image modulator (e.g., DMD), or the equivalent area of a film image (ala SMPTE RP40)? What format are the THX resolution test images, and are they line functions or sinusoidal?

Will there be THX test images to evaluate other aspects of the digital system, including the compression artifacts mentioned? Will these be the same as the SMPTE HD test images?

As far as the specifications for film Print Condition, IMHO, in-line film cleaning should really be part of the specifications. Relatively low cost in-line film cleaners have been available for years, and have found widescale use for special venue projection (e.g., IMAX theatres). Unfortunately, theatres showing feature films have been slow to take advantage of the significant improvement in quality they offer.

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John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Eastman Kodak Company
Research Labs, Building 69, Room 7419
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Cell: 716-781-4036 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion

The first thing I saw in the document concerning acceptable print damage bothered me a bit. It implies that after three weeks of running a print, it is OK to have "notable" (using the definition in the document) print damage and dirt accumulation, assuming the print is in good shape when the theatre receives it. A THX-certified theatre should have staff that can handle film and keep it clean for longer periods of time than that. Occasionally, I intentionally visit theatres and see movies they've been running for months, just to see how the prints have held up. At Regal River Oaks Cinema 8 in Decatur, prints stay in excellent condition. At other theatres, damage is either in the notable or significant categories. Film-Guard is out there and if it indeed keeps prints from getting dirty or damaged (and based on what I read here, it does), it should be used.

The "Viewer Conditions and Image Quality" looks like it summarises the specs in the equivalent SMPTE document(s). Have any of the figures been improved or increased over the standard recommended ones? In other words, if everything from the SMPTE recommended practices were removed from this THX document, what would be left?

The digital projection section looks like the film one with reduced resolution allowed (except for explaining digital artifacts in terms of how an average customer would describe them).

The sound quality section seems to have more recommendations above and beyond the normal "common-sensical" things that are in the image and environment sections. This is to be expected, since a large focus of THX is audio quality.

As for the document as a whole, it is great that these recommended practices exist. It does serve as a guideline by which to evaluate theatres to identify shortcomings. The items are good to use when designing a theatre from the start (although I'm sure THX has some specifications that are much more detailed and specific).

As I said before, if THX would in their recertification process, make sure that theatres are following these recommended practices and be sure that the projection equipment is well-maintained and providing images and sound that lives up to the standards, then the THX letters on a theatre's ad or marquee would mean much more. THX, instead of branching out and certifying all sorts of non-high-end-theatre related things, such as computers and VHS tapes, should pick a very small area (movie theatres and high-end home theatre equipment), stick to it, stay focused, and do it very well. Try to do too much and things get sloppy.

By saying what I've said here, I am not being a THX detractor. I'm simply telling you, the manager of the THX TAP, how the THX TAP can be improved. I'm sure a lot of what goes on at THX is beyond your control and you have to work within a framework there.

Evans A Criswell
http://home.hiwaay.net/~criswell/theatre/

------------------
John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Eastman Kodak Company
Research Labs, Building 69, Room 7419
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Cell: 716-781-4036 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion

All your questions will be answered in the very near future. The two engineers who helped me with the TAP Guidelines are currently out of town, but next week I'll have them answer your questions directly... especially those regarding Digital Cinema.

All your feedback is appreciated.

Thank You!!!

Yours, Ted Costas
Manager, THX Theatre Alignment Program

P.S. Evans C., you know I am only kidding you. Your passion for quality is vividly evident, and although you have been tough on me in the past, your thoughts are always welcome.
 

I know it always seems that I am tough on you. I don't mean to come across that way, but it seems that I do, even in the post above. Most of it comes from me being a mathematics and computer science person, which causes me, by nature, to analyze things very quantitatively. When a statement is made, I tend to try to analyze it mathematically and think, "Can I verify this, and how?"

I'm also from an academic background, and have been trained to look at works with a critical eye and analyze them from the viewpoint of what they contribute to the field. Most of the THX specifications seem to be an excellent summary of the appropriate ANSI/SMPTE specifications and recommended proctices. The document even specifies the documents from which the information was taken (which is good -- always provide references). However, my question of how much information would be left if the summarization from the ANSI/SMPTE standards and recommended practices were removed was asked to gauge the exact contribution of the THX document to the field. A summary is a good thing, but isn't really a contribution of new material. The audio section is the section of the document that I assume includes information concerning audio setup practices that are not included in the ANSI/SMPTE standards (I don't have access to many of those documents, so I could be wrong). So, the audio section is the main contribution of the document. This is the way that textbooks and research papers are judged in the academic world, by the way.

None of this has anything to do with being critical of you. Since you're the only THX spokesperson who participates here, and since you are the manager of the THX TAP, you're naturally the one to which concerns, criticisms, and questions get directed.

Well, have a good weekend (or what's left of it) .

Evans A Criswell

I like the idea of presenting a sort of quality control document that defines the pieces that make up the entire theater “system.” I feel that these guidelines are not for people like us, tech-types who usually only concentrate on the projection room; we already know what SMPTE standard to look up. It’s for people who do several jobs at once, like ushers who must thread, pick-up the auditorium then sell tickets or candy.

For example, the guideline tries to define print condition by separating damage from dirt accumulation (separate the individual elements of something to more easily measure whether the total is acceptable.) I don’t remember anyone trying to do it like this before. (Reminds me of the RST system in amateur radio.) If I need to describe a print condition to another experienced operator, I know I can just say, “It’s not that great for only 2 weeks.” because we both have seen new prints, and beat to death prints, and how long a print should last. But, an usher who just started working doesn’t have the experience yet to judge or describe print condition. Yes, it’s still subjective, (so is looking for line pairs on focus and resolution charts) but before there was _nothing_; now there’s _something_.

I totally agree with Evans C on two issues: The standard for print condition should be tougher. At a minimum, I would bump it up a week- such that it takes fourteen days for “very minor”, 21 days for “minor.”

And: If digital gets away with lower spec’s for focus and resolution, it seems unfair. It probably is low so current digital systems can pass, (and to be fair, is certainly not under THX/TAP’s control; at least a minimum is being defined) but it tends to legitimize a lower quality presentation.

Under “Masking (condition and placement)” it says “If operable, the masking should adjust to proper aspect ratios….” I would delete the, “If operable” If I had to choose, I’d take no masking with proper ratios shown, than fixed 2:1 masking. Again, by printing a statement like that, it legitimizes (IMHO) a totally unacceptable practice.

In “Sight lines and floor pitch” it suggests that “Riser seating should be regarded as an important consideration for future theater designs.” I would tend not to agree. Riser (stadium) requires people to climb up or down stairs, (not good in the dark) reduces the number of seats you can install, (admittedly only slightly) and costs more. By designing the auditorium correctly with staggered seating, proper slope and positioning the screen correctly, I think excellent sightlines can still be achieved without the problems of riser seating. I would agree if the auditorium was very deep (over 100 feet) but few are in today’s designs. (I’m thinking of some SMPTE articles by Schlanger.)

For “Digital Sound Format” I agree that all theaters should have one digital sound format. The reduced maintenance makes it well worth it. But, somehow the statement should be made clear that you can’t just bolt a digital soundhead to your existing analog system and be done. The rest of the sound system must have the headroom, etc.

But, again, I like it. I’d like to see more stuff fleshed-out.