CheckSum

First of all, this is not a deep dive into checksums as a thing, but rather about their usage for digital media-based art and design – specifically in the context of institutional acquisitions and archives. There are two (and probably more) great ways of using checksums that I’ve discovered so far. The first case is for archiving, and the second is for duplicates.

A checksum is a way of generating a unique number for an individual file. This unique number helps anyone validate a file. The checksum can help determine if the file you have is indeed the file it’s supposed to be, or if something is wrong when the numbers don’t match. Did something happen during the internet-transfer-sea-road? Or has bit rot started to occur on your 20-year-old hard drive? When sending any file, either for archiving or playback, the receiver can check the checksum to ensure it matches the original checksum, confirming that the file is correct and ready for playback (so other playback issues can occur... BrightSign, am I right!). In other words, a checksum is a useful way to know if the file is indeed an “original” – ensuring they are one-to-one. For example:

Master:	ff88c59b30b9c602f678e63236145412
Receiver:	ff88c59b30b9c602f678e63236145412

Everything is in order (#^.^#)

Master:	ff88c59b30b9c602f678e63236145412
Receiver:	c24429b7ccb7d9446511ed202a98d5d2

Something happened along the way (ー_ー)

For this ToolSupply “sticky note” #1, we are looking at video files as an example. The final file is finished – like in _final_final_final.mov – and you are preparing it for storage or acquisition. By the way, this is Mac-only (working on the Windows version). Open up Terminal and copy one of the checksums above. Either use md5 it’s the fastest and generates a “shorter” number, though it’s considered less secure compared to SHA-2 – (but that's for another topic). Some institutions/collectors prefer one over the other.

Terminal →

md5 / shasum -a 256

Drag (or copy path) the file you want to generate a checksum for, into the window, making sure there is a single space between the pre-text and the dragged file, then hit enter. If it’s a big file, it might take a while to generate the number. A great feature is that you can highlight multiple video files and drag them all into the Terminal window, then hit enter (took myself many single drag and drops to find out that this was an option). Terminal will go through each file one by one. Below is the file structure I use, and it’s also advised to make a construction list of how the video file was made. It can be particularly helpful to note down which version of the program you are using, such as Final Cut Pro 10.6.5, Cinema 4D 2025.1.2, etc. – everything that is important to know if the file needs to be restored in any way.

QuickCopy: Master file setup

[Master] Name: Artist: md5 checksum: SHA-256 algorithm: Container format: Resolution: Data size: Over all bit rate: Video format: Audio Format: Encoded FPS: Duration: Loop: Color Primaries: Construction: Text file updated:

QuickCopy: Exhibition file setup

[Exhibition copy] Name: Artist: md5 checksum: Container format: Resolution: Data size: Over all bit rate: Video format: Audio Format: Encoded FPS: Color Primaries: Exhibition Copy Notes: