Film look (also known as filmizing or film-look) is a process in which video is altered in overall appearance to appear to have been shot on film stock. The process is usually electronic, although filmizing can sometimes occur as an unintentional by-product of some optical techniques, such as telerecording. The effect is the exact opposite of a process called VidFIRE.
Differences between video and film
Frame rate: 24 frames per second for film, 30 or 40 frames per second for old SD video. Modern video cameras shoot 24 and up as well. Shutter angle: Shorter (90° to 210°) for film, often ~350° for old video. Modern video cameras have adjustable electronic, or – in Arri's video cameras – mechanical shutters. Dynamic range: film and video systems have widely varying limits to the luminance dynamic ranges that they can capture. Modern video cameras are much closer to the dynamic range of film, and their use is better understood by directors. Field of view and depth of field: Depth of field is tangentially related to the size of the image plane, however, it is a popular misconception that the image plane is directly related to DOF. Smaller image planes (whether film or sensor) require a proportionally smaller lens to achieve a similar field of view. This means that a frame with a 12 degree horizontal field of view will require a 50 mm lens on 16 mm film, a 100 mm lens on 35 mm film, and a 250 mm lens on 65 mm film. And a 250 mm lens delivers much shallower DOF than a 50 mm lens does. It follows that standard lenses on most consumer video cameras with small sensors provide much larger depth of field than 35 mm film. Digital cinema cameras like the Red One or Panavision Genesis, as well as some digital SLR cameras with video capabilities, (such as the Canon EOS 5D Mark II), have sensors roughly equal in size to 35 mm film frames and thus show the same field of view characteristics. Photo-chemical color-timing/grading: only possible with film; white balance adjustment for video performs a similar function. Noise type: film grain noise generally differs both statistically and visually from digital sensor noise. However, artificial noise can be added to video, to simulate film grain. Jump & Weave: Images projected from film do not always align properly from frame to frame when projected on screen due to minor variations in sprocket hole size.
Frame rate
Today, most digital cinematography video cameras in use feature 24p format (24 progressive frames per second).
When shooting with old cameras, 50 Hz interlaced video (usually used with most forms of PAL and SECAM) can be relatively easily processed to give 25 progressive frames per second, which is the framerate that the PAL/SECAM telecine process also uses. Every two video fields can be "blended" together, every other field can be decimated and the remaining fields can be shown for double the length (this noticeably reduces vertical resolution), or a motion estimation process can be applied to achieve one frame out of every two fields. This technique is sometimes called Field-removed video or FRV. Some modern PAL video cameras do offer the ability to produce 25 frame-per-second progressive video, negating the requirement of post-processing the video to get a temporal similarity to film.
On the other hand, it is much more complicated to convert 60 Hz interlaced video (used with NTSC and PAL-M) to a framerate resembling that of film. Doing the same as PAL/SECAM filmizing will yield 30 frame-per-second video, which is significantly faster than film. Two out of every five fields could be dropped (and 3:2 Pulldown can be applied to the remaining fields), but any motion after this process will look very uneven. Sophisticated computer motion estimation and field blending is usually used to convert NTSC video to 24 frames-per-second – something which could not have been done until recently, and still does not yield as realistic results as PAL filmizing conversion.
Many computer editing programs can de-interlace video to give it more of a film look. An interlaced frame is actually the combination of two fields, one providing the odd-numbered scan lines and the other the even-numbered. Interlacing results in a type of motion blur known as "combing", and also shows "interline twitter" where vertical details approach the resolution limit, neither of which occur in film. De-interlacing can remove or reduce these artifacts, resulting in an appearance closer to that of film.
Some inexpensive consumer editing programs achieve de-interlacing by deleting one of the fields. The result gives half the vertical resolution of the original frame, and sometimes adds a jagged effect to the picture.