Beginning work on this animation involved making two decisions that were not as simple as I thought they would be. The first was deciding on an image aspect ratio. I thought of using use the same proportions as my landscape paintings, which are usually between 2:1 or 2.35:1. The painting below, "Row of Trees", is 2.35:1 which is in my comfort zone for working with composition intuitively.
The problem with using this ratio is that the animation will likely be viewed on screens smaller than a 6ft canvas, and will require letter-boxing. Letter-boxing is when, on a typical HDTV display, there are black bars at the top and bottom of the screen. This is common when a Cinemascope film is shown on television in its original format. Depending on screen size this can be a problem, with the much image detail being lost. After experimenting with different formats, and seeing how common letter-boxing is now, even in television advertising, I decided to go ahead with a compromise 2:1 ratio, with a resolution high enough so it can be viewed at any size, including projected onto a screen. The smallest method of viewing where it would still be a worthwhile experience is on an ipad, where letter-boxing still looks... ok, at least to this eye. Anything smaller, like on a phone, and most of the imagery will be lost anyway.
The second decision was frame rate. The most common frame rates are 24 fps for a theatrical film release, and around the 30 fps mark for video and television, with 60 fps slowly becoming more common for video and some theatrical films. It is easy to see the difference between 24 fps and higher rates. 24 fps has a “cinematic” feel whereas higher frame rates have a video feel, sometimes called the soap opera effect. I remember noticing this difference between film and television as a child and not being able to put my finger on it. Somehow with higher frame rates the artificial quality of the sets and the acting were more obvious. Even today when higher frame rates are used in a big budget production, like with the recent Hobbit release, it takes away from the illusion and especially the scale, revealing actors acting, and sets and CGI that are somehow smaller. This is not just personal taste. It is a well known factor and the reasons for it are debated. Early film makers chose 24 fps because film stock was expensive and using fewer frames saved money. It was not for aesthetic reasons, and this choice became the standard for the same practical reason. Yet, whether it was intentional or not, something was hit upon. 24 fps is right at the threshold where a sequence of still images will blend into continuous movement. With higher frames rates the movement becomes more and more three-dimensional as the still, flat, images are no longer perceived, even subliminally. The result is an experience similar to an exercise in perception done by painters, where the painted surface is made to fall away. 24 fps retains a subtle flatness, a subtle perception of the screen as a flat, luminous, composition, balanced with the illusion of depth within the imagery. This is very much like representational painting, where the art of illusory depth and the craft of a beautifully painted surface are (hopefully) in perfect balance. At higher frame rates, especially at 60 fps, that flatness is lost, and with that, a certain painterly scale. The scale of the movie as a rectangular object is lost to the illusion of depth.
Retaining this flatness is the main reason I chose to go with 24fps, but there is another reason that echoes the reasons of early filmmakers, cost, which for a CG animator is a time cost. Regardless of what animation platform is used, the individual frames will have to be rendered one at a time, either on a your own computers or through a render farm (a network of computers dedicated to rendering). Even with a good computer, rendering a high resolution sequence of 1500 frames at 24 fps, just sixty seconds of run-time, can take many hours, or even days. At higher frame rates production can become impractical, unless a render farm is used extensively, which can be expensive.