Is transferring Super 8 Film to 5K Overkill? No and Here Why!
Filmmakers often ask us what would be the benefits of scanning super 8 film to 5K given that the maximum resolution of the tiny frame.
No one can debate the benefits of more pixels. The more pixels you have to define an image the truer you can make an image to the original. This is true for still photography (which is why you now have all those multi mega pixel cameras) and equally true for motion picture film. With older scanning technology, these large files were only possible to achieve with an uncompressed format. These uncompressed files were difficult to work with on an average home computer and edit system. With 5K data scans however, there are new options.
The Codec Moment: DPX vs FCP (Pro Res)
There are 2 ways to get more pixels from the scanning of film to digital. First, as we said is to use uncompressed digital files typically DPX*. A DPX file will be about 10 times as many pixels compared to the same file encoded as a FCP* Pro Res file. The other way is to scan using a larger digital size such as 4K or even 5K. By comparison, a 2K scan in DPX is about the same size as a Pro Res 422 HQ file done at 5K.
There are several advantages of using larger Pro Res files rather than DPX files. First, Pro Res can be edited using Final Cut Pro, one of the most popular edit programs. FCP does not accept DPX files. You will have to check your edit package to see if it supports DPX or Pro Res. It is important to sort out this workflow before you choose how you will digitally master the film. The other advantage is that Pro ReS files are continuos, so they transfer much faster to and from your Hard Drive. DPX are individual frames and must be sent as such. This causes a slowdown in the transfer process. For example, our system will download 100 gig of Pro Res in about 15 minutes using a USB 3 connection, where the same files size of DPX will take over an hour. This is critical when you are trying to do a production with the highest quality but are against production deadlines.
Are You Being Framed?
5K scans are typically done as an overscan either just beyond the frame or using the full format. For the most part, a Full Formant Overscan is done for the aesthetics of using the film sprocket as part of the image. A Standard Overscan is done for several good technical reason. First it insures that all the image area is scanned. In the past, typical telecine transfers were done Framed which meant that you had to crop in slightly so that the frame line did not appear in the image. Depending on how conscientiously the scan was done there might be a little crop in the image or a lot. With an overscan, there is no need to worry about lost picture as you see the complete image beyond the frame line. Another problems is that the position of the perfs can be inconsistent given different models of super 8 camera. This means the image must be framed up or down to adjust for this camera error. Older scanners might have tried to adjust for this or they just cropped in enough to make up for it cropping deeply into your frame. An Overscan can be set so that no matter how many cameras were used, you still get all of your image. The last reason to Overscan is that you might want to do stabilization of your image, and you would use the frame line or the perf as one of the parameters of this process.
Another example of the benefit of larger files in 4K or 5K is in how they react to Post Processes. Common tools such as Dirt Concealment (Dust Busting) and Grain Process ( Grain Reduction) respond better when there is more information. These programs need data to analyze and the more you give them the better job they do with the process. 5K scans are always using Progressive Image Technology*. This mean there is never a issue with Interlace Artifacts .