Ed's view - The "Film Look"
Posted 30 August 2005 - 01:58 PM
By Ed Milbourn on August 30, 2005
As HDTV becomes increasingly popular as both a production and display medium, the subjective differences between motion picture and video originations become more apparent. This is because HDTV reproduces the image more accurately than SDTV, i.e., by definition HDTV is much more "transparent" than SDTV.
The motion picture film image has significantly different qualities than images produced by video cameras. There is not one specific factor that characterizes the difference, but a litany of them. Interestingly, attempts by engineering texts to quantify and precisely define the "film look" have met with dubious success. This is little agreement as to the exact characteristics defining the film image. It is a "you know it when you see it" thing - very ephemeral. Subjective characterizations such as smooth, muted, and surreal are identified with film as compared to video characterizations such as sharp, harsh and vivid.
There are many aspects of motion picture film photography, processing and production techniques that contribute to the "film look." Some are perhaps more significant than others, and all are exploited by directors and cinematographers to achieve a desired visual "mood," similar to the use of music. Great pains are taken in the movie-to-DVD authorizing and video retransmission processes to preserve these specific film production qualities.
It is important to note that the "film look" can be emulated purposely by video producers. Although most of the prime time HDTV productions are originated on 35mm film - not video, various cinemagraphic, lighting and postproduction techniques can be employed to give video originated productions a decided film produced quality.
Let's now take a look "under-the-hood" at these various "film look" characteristics as compared to video.
The "smooth" look can be attributed to several factors. Most importantly is the way the film grain structure defines image edges. A close examination of film edge transitions indicates that the pixel brightness tends to drop off more slowly than video. Since the film grain structure is much more dense than the video pixel structure, the image edges are defined by the brightness gradients maintained by the dense grain structure. The video images, even with HDTV, are defined by a much coarser pixel structure. This means that the image edges can be artificially defined by the pixel structure, creating a much sharper edge transition cut-off. This effect is exacerbated with SDTV by excessive "peaking" or "sharpness" enhancement techniques.
Progressive scan, which minimizes the visible horizontal scanning line structure, and 3:2 pull-down, which virtually eliminates the film to video transfer temporal artifacts, also contribute to the "smoother" film-type-look.
The muted color look of film is due primarily by the reduced amount of color saturation permitted during film processing and production. In the early days of color film, color was showcased by highly saturated images, as is evidenced by early Technicolor movies such as Gone With The Wind and The Wizard of Oz. Today, the cinematographers judiciously use color to add just enough realism. In addition, film color temperature is much lower than video, giving uncorrected film color a much "redder" tint. Thirdly, the video color gamut is somewhat greater than that of film. This gives video the capability of reproducing a slightly wider range of colors than film, adding to the color "snap" of HDTV video. All of these factors (and a few others) combine to give film color a more muted, realistic look than video.
The high sensitivity of today's film stock gives cinematographers great flexibility in the use of low light effects and depth-of-field. "Depth-of-field" refers to the distance objects appear in focus behind and forward of the primary object in focus. Most film cinematographers make full use of the depth-of-field capability; making sure objects in the background are highly defocused so that the viewer is directed only to the object of interest. This background defocusing adds to the overall film "soft" or "smooth" look.
Low light effects such as high-contrast highlighting, particularly of actors' faces, is a film technique not generally associated with video. Note that the majority of scenes of both today's theatrical and film-based productions (e.g., most prime time programming) are shot at very low light levels. Law and Order, West Wing and CSI are good examples of the low light effects used. These low light film and video/film-emulated techniques greatly add to the "film look."
There are other factors such as contrast, dissolve, polarization, grain, film stock, projection ratios and others too numerous to mention that contribute to the film look, but those described are the most salient. With today's films and electronic filters, video can be made to look like film and film can be made to look like video. The "look" of the image is clearly a production choice, not a technological one. The ability of HDTV to faithfully reproduce the look desired by the production team is a very important attribute of HDTV. This means the full creative capability of both media can be had in every HDTV home. It only gets better.
About Ed Milbourn
After graduating from Purdue University with degrees in Electrical Engineering and Industrial Education in 1961 and 1963 respectively, Ed Milbourn joined the RCA Home Entertainment Division in 1963. During his thirty-eight year career with RCA (later GE and Thomson multimedia), Mr. Milbourn held the positions of Field Service Engineer, Manager of Technical Training and Manager of Sales Training. In 1987, he joined Thomson's Product Management group as Manager of Advanced Television Systems Planning, with responsibilities including Digital Television and High Definition Television Product Management. Mr. Milbourn retired from Thomson multimedia in December 2001, and is now a Consumer Electronics Industry consultant.
Posted 30 August 2005 - 11:36 PM
>>In addition, film color temperature is much lower than video, giving
>>uncorrected film color a much "redder" tint.
I thought CCD's were calibrated to 3200K. I'm pretty sure no one makes stocks balanced for below 3200K. Oh, and that "redder" film tint is dependent on both film stock and processing, I'd think...
>>Thirdly, the video color gamut is somewhat greater than that of film. This gives
>>video the capability of reproducing a slightly wider range of colors than film,
>>adding to the color "snap" of HDTV video.
Har, har. That "snap" is the exact opposite of a wider color gamut, wouldn't you say? Since when does color quantization = a "somewhat greater" color gamut?
>>Most film cinematographers make full use of the depth-of-field capability;
>>making sure objects in the background are highly defocused
Depends on the subject matter!
>>the majority of scenes of both today's theatrical and film-based productions
>>(e.g., most prime time programming) are shot at very low light levels.
Since when? If anything, light levels for a film-based production would be, in general, greater than those for a video-based production.
Posted 01 September 2005 - 08:41 AM
That depth of filed thing is an issue with me right now also. I spent the past two days watching some old movies to look specifically at the DOF to get an idea of how much they used blurring of backgrounds back when there were still some good movies made. I was curious about it because it seems to be the big objection issue for people disparaging DV cams. True, unless you pay another 8-grand for a 35mm lens (mini35 for instance) you won't get much of a blur on backgrounds in close places. But I've come to the conclusion that around 75% of those blurred backgrounds we see in modern movies is completely unnecessary anyway, and may even hurt more than they help. Of the old movies I watched, (How Green Was My Valley, The Thin Man, Laura, and On Borrowed Time), HGWMV was the only one to use very much background blurring. In fact I think Arthur Miller was one of the first to really do very much of this. But even he used it sparingly compared to what I'm seeing today. And because he used it sparingly it had a greater effect. There's a great scene when Roddy McDowall walks from one side of the kitchen to another while gazing wistfully at his brother's soon to be bride, and lays his head against the wall while staring at what he perceives as great beauty. The background starts to blur as he starts his slow walk and then gets completely blurred by the time he puts his head against the wall, really making you almost feel what he feels. Now that?s the way to use DOF. And personally, I tend to think that the more reserved amount of DOF that DV cams provide will probably help new filmmakers to make better films without the modern cliché that DOF currently enjoys. But that's just my opinion, and not one from somebody who knows a lot about cinematography yet. But I'm trying to learn, and I'm just telling you what I think when I see this stuff as a film "watcher".
Posted 01 September 2005 - 10:47 AM
It has diddly squat to do with "film vs video"
Posted 01 September 2005 - 03:11 PM
Posted 02 September 2005 - 05:52 AM
> A close examination of film edge transitions indicates that the pixel brightness tends > to drop off more slowly than video
I think that's a rather simplistic way of looking at it, which on its own implies film has lower resolution. I think on individual frames it often does, but we're all familiar with the factor of summing grain over several frames.
> Progressive scan, which minimizes the visible horizontal scanning line structure,
> and 3:2 pull-down, which virtually eliminates the film to video transfer temporal
I'd have said the exact opposite. There's a lot less difference between the motion rendering of video and film in PAL countries where film is shown as part of a 50i stream.