Variants are used by Capture One to display the original RAW, JPEG, TIFF, DNG, PNG, or PSD source files and to store the adjustments you have made. To understand the concept of variants, you need to observe Capture One as a kind of non-destructive rendering engine. This non-destructive approach means that edits are never saved to the original files. Capture One reads the original source files and then determines how they should look on-screen based on some default factory parameters. A small preview file for each of your images is then made and this is what you see in the viewer.
When you adjust an image, the instructions are written to a small BLOB of data called settings. The application in real-time then re-reads the updated settings updates the preview then. We call this a virtual representation of a variant. In effect, what you are looking at on-screen is always a virtual representation of what the final file will look like once the image is processed or exported. This concept of a variant exists as a sort of transition from the source file to the output file.
Each variant is referred by the name and format to the source images (wherever they’re stored), so you can logically connect them to the previews on screen. There are many benefits of variants: they can be copied as many times as you like and can even exist in more than one place (in the form of albums). All of these virtual copies can exist as a representation of just one original source image. When it comes to exporting the final file, Capture One doesn’t make any changes to your source images. Instead, it combines the original image data and adjustments you have made and makes a copy in the chosen format that a pixel editor can read.