developed by Peter Finklestone to address the motion differences caused by the telerecording process. It uses motion estimation software to create an intermediate image, which exists temporally between two film frames. For example, if all frames of a twenty-five-minute film recording were processed, the result would be double the amount of frames and a new running length of fifty minutes. Playback at this stage (at 25 frame/s) gives smooth movement at half speed, due to the presence of interpolated images. The programme is then further processed by interlacing adjacent frames, which halves the running time back to the original twenty-five minutes. The final result is video with fifty fields per second, alternate fields being sourced from the original film frame or the new interpolated image respectively. This has the effect of restoring the "video look" to the production. Limitations Depending on the quality of the film stock and how carefully the film was stored and handled in the years since it was first recorded, film recordings can be very grainy, dirty and scratched. The appearance of these film artefacts on the processed programme would break the illusion that the viewer is watching a videotape recording. Therefore, to maintain the VidFIRE effect it is imperative the image be as clean and stable as possible. The best available copy of the film-recorded programme should be used, preferably the original camera negative. Before processing, the film should be cleaned, digitally noise-reduced, and repaired. A further, self-imposed limitation is that VidFIRE is used only to process material that originally was produced using video cameras. There is no technical reason why film-originated material cannot be processed, but it is not considered to be "in the spirit" of restoration. It is also possible that the difference in lighting and picture balance on film may mean the final processed images look subjectively "wrong". Commercial use for Doctor Who episodes The Doctor Who Restoration Team routinely VidFIREs 1960s episodes of Doctor Who when preparing them for release on DVD. The process has also been applied to a number of other programmes, including two previously lost episodes of the BBC sitcom Dad's Army, which were rediscovered in 2001. The episodes, "Operation Kilt" and "The Battle of Godfrey's Cottage," were VidFIREd in preparation for their broadcast as part of a "Dad's Army evening" on BBC Two. The remainder of series one and two of Dad's Army was later processed and