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By Joe Kleiman

50 million individual pixels.  As computed by Evans & Sutherland, that’s the number of pixels projected on a dome with a True 8K digital fulldome projection system.  A smaller system, comprised of five 4K DLP projectors can achieve a 35 megapixel image, approximating the True 8K experience.  But can such a powerful system take on and match the king of all film formats, 15 perforation/70 mm (1570) film, in both image and light output on a dome?

On October 22, 2014, the Giant Screen Cinema Association (GSCA) hosted a Digital Dome Day at The Dome, the giant screen dome theater at the Science Museum of Virginia.  The industry event featured a first of its kind side-by-side comparison of 1570 film with 8K digital fulldome projection.  According to Tammy Seldon, Executive Director of the Giant Screen Cinema Association (GSCA), “This was a unique opportunity of us to do this. It’s difficult to install temporary systems like this in domes and here we had a theater available to us with both kinds of systems.”

The Digistar 5 fulldome 3D system featured in the “shootout” is comprised of five Christie 25,000 lumen DLP projectors at 4K resolution running at 120 Hz. The combined resolution of these projectors produces over 29 million pixels on the Museum's giant 23 meter (75 foot) diameter dome, almost three times the resolution of a 4K fulldome theater, and over 14 times the resolution of HDTV. This system offers a brightness of 4 fL on the dome, currently the highest brightness ever projected in a giant screen digital fulldome theater.

For the shootout, a seam was created halfway through the screen, with a specially designed lenscap on the film projector and masking of the digital projectors.  The 65mm film was scanned at 4K x 3K and warped to 4K x 4K dome masters.  Todd Slisher of the Longway Planetarium in Flint, MI noticed that the digital image, unlike the film, “lacked any dust, film yellowing, or film jitter,” while James Neihouse, a experienced giant screen cinematographer was “surprised at how much wiggle there is in the 1570.  I hadn’t noticed that in the past.”  Neihouse also pointed out that with the warping capabilities of the Digistar 5, film artifacts and image distortion can be eliminated.

Since 1570 film is projected onto a dome screen through a fisheye lens, distortion appears throughout the image, especially at the edges of the screen, where the image tends to stretch.  During the Digital Dome Day session, a demonstration was made using three different warps – a traditional IMAX warp, which replicates the image being projected through a fish-eye lens; an expanded film warp, which covers more of the dome while preserving the fish-eye film warp; and E&S’s patented dome warp, which removes the fish-eye effect, providing for a clear image with no stretching across the dome screen.

Long time consultant to museums and planetariums Ian McLennan was impressed with the warp technology and what it might mean.  “Some things will probably never work on the dome (especially scenes that contain strong vertical elements), but corrective warping might help minimize, if not fix that issue." 

A decade ago, a successful digital replacement for giant screen film on the dome was the thing of dreams.  In 2005, digital cinema technology was beginnig its advance into cinemas.  A succesful test of 1.3K digital cinema projectors in the commercial market had just been completed, the deployment of the first wave of 2K projectors into cinemas throughout North America was about to take place, and Digital Cinema Initiatives, a consortium sponsored by the major Hollywood studios, presented its first draft of standardized specifications for the technology. 

The equipment manufacturers laid forth a platter of incentives for cinema owners to switch to digital – lower operating cost, image equivalent to a 35mm show print, and the possibility of alternate programming, such as live broadcasts in high definition.  In those early days of deployment, theater owners balked at the concept of showing anything other than movies.  John Fithian, President of the National Association of Theater Owners, coined a term for the concept – “Other Digital Stuff.”  Abbreviated to an acronym, it was pronound “odious.”

However, giant screen theaters, especially those theaters located in museums and other educational institutions, already had a well established history of showing alternative programming.  As the majority of a film-based giant screen projection booth is inhabited by a large projector and support equipment to run to 1570 film, a format with a frame nine times the size of 35mm and a length of 3 miles for every 40 minutes of film, other equipment needed to be shoehorned into the space for other formats, including 35mm and digital video.  In a giant screen dome theater, as the projection booth is located under the seating area with the projector elevated to the center of the audience space via an elevator, this necessitated the construction of a secondary projection booth at the top and rear of the dome.

Although a few giant screen theaters immediately sought out a digital solution, the industry as a whole remained a few years behind mainstream cinema in accepting the new technology, mainly due to issues with digital cinema’s inability to match the 1570 light output or image resolution, computed by IMAX’s David Keighley as 18K per frame.

In 2008, companies such as IMAX and D3D Cinema began integrating dual projection systems for giant screen theaters, first based on 2K digital cinema projectors, then on 4K.  Digital Immersive Giant Screen Specification (DIGSS), now under the stewardship of the GSCA, was initaited to “support a museum’s needs for immersive learning that are distinct from Hollywood cinemas, particularly with regard to screen size and image aspect ratio (4:3, +/-) that most clearly differentiate the current global giant-screen (GS) network fromconventional movie theaters.” In January 2012, the shootout took place between a 4K laser projection system and 1570 film at Moody Gardens in Galveston, TX.  The event was considered by many to be a benchmark moment that defined the acceptance of digital as an alternative to giant screen film. 

While many flatscreen 1570 theaters were using conventional cinema solutions for their conversion to digital projection, one of the most practical solutions for replacing 1570 film on a dome was being developed within the planetarium community.  Digital dome, utilizing multiple projectors and blending software, would fill this gap.  Prior to installations inside 1570 domes, companies such as Evans & Sutherland (E&S) and Sky-Skan began working with giant screen film producers to make their films available for fulldome projection.  In 2008, Michael Daut of E&S approached National Geographic Cinema Ventures about offering their hit film “Sea Monsters” for digital fulldome theaters.  As of last year, “Sea Monsters” was the highest performing giant screen film in their library, which now numbers more than forty titles.

n forty titles.

Justin Bartel at Science Museum of Virginiar, Photo Courtesy of Sean Dewitt Photography


With the E&S Digistar 5, Digital Dome Day participants at the Science Museum of Virginia were able experience a variety of programs, including giant screen movies, some projected in 3D on the dome using active glasses, pre-rendered planetarium and fulldome programming, and a voyage through the universe rendered in real time.

A number of those in attendance at the Digital Dome Day felt the Digistar 5 to be a viable alternative to film projection on a dome.  Some called the event a benchmark moment, equivalent to the Galveston event. 

The museum is now showing a wide variety of giant screen films in The Dome, with the ability to acquire them for either film or digital playback (some giant screen films have not yet been made available for digital dome systems).  It’s also running a daily astronomy presentation, which is comprised of a combination of a pre-rendered show with a live tour through space.  A demonstration of this live component proved to be a hit among the event attendees.  McLennan points out, “This is opening up possibilities for programming.  You could integrate live info such as rocket launches into pre-rendered animation.  Seamless programs using both pre-rendered and live is holy grail.”

The Science Museum of Virginia may one day achieve that goal.  Already, they’re able to edit and integrate live video feeds into the real time presentation within minutes of broadcast. 

Since switching to the digital system, the museum has seen an increase of 30-40% in attendance over the prior year.  As Jim Peck, the Museum’s Director of Technology and Innovation, stated, “Our mission is inspiration—and we find that we are now able to exceed our guests' expectations.”

Attendees to the Digital Dome Day were impressed with the various demonstrations, especially the digital vs 1570 shootout.  Emblematic of many attendees’ perceptions was Toby Mensforth, whose impressive pedigree includes managing theaters for the Canadian Museum of Civilisation, IMAX Corporation, and Smithsonian Enterprises.  Of his experience, he remarked, “If I were still a Giant Dome theater operator, I would be proud to have this quality of image on my screen."







OCT 22, 2014


Todd Slisher, Sloan*Longway Planetarium:


"Before this demonstration, I had been a skeptic of digital multi-projector systems.  The digital image was very good against 1570.  The colors were more saturated and intense.  Unlike the film image, there as no dust, yellowing of the image, or film jitter.  The Digistar image, coming from six Christie projectors, was very well matched across the entire frame with no blending issues.   The 1570 image showed some severe warping issues, but the warping software on the digital system allowed the image to fill almost the entire dome."


Tina Ratterman, Big & Digital:


"The colors on the digital projection were much more vivid and vibrant than film and the image quality was excellent in 8K.  This is a really good solution for 1570 dome theaters considering converting to digital or laser that will provide new opportunities for programming giant screen content and astronomy demonstrations."


James Neihouse, Cinematographer:


"For theaters showing film - digital dome projection is a good step in the right direction.  It provides flexibility and great fun stuff for programming.  With the warping capabilities, artifacts can now be taken care of and we can get rid of distortion, which I find very interesting."


Toby Mensforth, Mensforth Associates:

" As far as I know this is the first time 1570 film's been compared "side-by-side' to Digital on a dome. This GSCA event was another industry benchmark, equivalent to when 4K was compared to 1570 on a flat screen. I have to say that I was very impressed at how well the digital image showed compared against the selection of 1570 film screened.  For me there was not a noticeable difference and I thought that the content that was originated in film showcased almost the same in both formats.  There was little to choose between the two. Anything that had originated digitally looked absolutley superb on the dome. If I were still a Giant Dome theater operator, I would be proud to have this quality of image on my screen."



Howard George, Michigan Science Center, over 20 years projection experience with 1570 domes:


"To the naked eye, the brightness and contrast were very comparable as we watched different content put on-screen.  The IMAX film seemed washed-out, brownish, and shaky, while the D5 looked sharp, blueish, and steady as all get-out.   I was convinced  of the digital systems’ superiority over the film system as far as projecting traditional full-dome live-action and animated content.  The IMAX manages to be slightly brighter, but the D5 won in terms of color, stability, and contrast. I’d call resolution a tie between the two, with the digital system winning an easy victory in terms of overall image quality.  There was a pastoral image scanned at 3k by 4k from IMAX film. This is when my jaw hit the floor. The picture looks nice. In person, it was eye-popping, glorious, and undoubtedly among the best full-dome images I’ve ever seen.  Unlike IMAX, the image went all the way back to the exit doors, completely filling the screen. My general impression after the demo was that IMAX film has finally and decisively been surpassed."


Tammy Seldon, Giant Screen Cinema Association:


"The GSCA is very proud to have sponsored the first giant screen comparison of 1570 vs digital on a dome and look forward to having many similar events in the future as more 1570 domes add digital systems. A number of our members said this was a benchmark moment equivalent to when 4K digital was demonstrated side by side with 1570 film on a flat screen.  Even two or three filmmakers told me that after this demonstration, they are now comfortable with showing their content on a digital dome, that we are technically now there.  This is indeed a valid option for theaters that want to show giant screen films and for filmmakers looking to showcase their films on the dome. "


Ian McLennan, Consultant to the Stars


"The demonstration proved conclusively to me that digital is here and is the wave of the future. I was quite impressed with the warping technology that E&S brought to the table.  Some things will probably never work on the dome (especially scenes that contain strong vertical elements), but corrective warping might help minimize, if not fix that issue.  Film had a distinct movement within it, which you can't escape, but whatever differences existed between the two formats was otherwise negligible.  The images were reasonably close enough.  I would recommend digital projection such as Digistar as a viable alternative to film."


Stephen Low, Giant Screen Filmmaker


"There were some marvelous shots with the digital projector that told me that the basic standard is going to work.   I was surprised the warp worked so well.  In theory digital projection has some real advantages over a film.  You can adjust the contrast, color, you have more control over distortion and warping.  I do think that quality control with so many projectors is going to be a challenge for sure.  It’s all in the details, just like film projection.  

“Film seems to be going away, maybe next year and it will be very hard to get new prints for the dome unless someone else picks up the technology.  After the demonstration, I have a positive sense that the digital dome can deliver. In the end a filmmaker looks at any medium both in capture and projection and tries to figure out how best to use it. The dome will remain immensely challenging shot by shot by shot.  Sloppy shooting has always been worse in a dome than on a flat screen and it will remain so.  Giant screens in general are more difficult to use but much more fun and rewarding in the end.  Digital or film, some things never change.”



Paul Fraser, Blaze Digital Cinema Works


"The split-screen comparison between 15/70 film and digital fulldome was the highlight of dome day. (Kudo's to E&S for pulling off such a technically challenging demo). For me, this was a groundbreaking demo that instantly burned into my memory. It was proof of a very important industry development: that digital fulldome can be an acceptable replacement to 1570 film for the truly giant domes, from a quality of image standpoint. That said, the industry still has some work to do on standards and business models, and the total costs of all new digital solutions for giant domes have to be taken into consideration too, if fulldome is to realize its full potential as a replacement for 15/70 film. But this event took the image quality issue off the table, and my sense is that the word-of-mouth following the event has accelerated interest in exploring fulldome as the digital path forward for many domes."

Related articles;

James Hyder LF Examiner

Evans & Sutherland True 8K

GSCA Digital Dome Day


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