Use video editing software (like Adobe Premiere Pro, Final Cut Pro, or free alternatives like Lightworks or Shotcut) to edit your footage. For a retro or "old" look, you can apply specific color grading techniques or use LUTs (Look-Up Tables) designed to give your footage an aged appearance.

In the context of cinema, "old 4K" refers to the process of remastering classic or vintage films into resolution.

If you have access to a 4K camera, shooting in this resolution ensures your content is of high quality. Even if you're planning to release it under an older or more retro aesthetic, starting with a high resolution gives you flexibility in post-production.