Practical guide
Check Whether On-Screen Text Survives a Small View
Evaluate labels and instructions at the size you will actually use.
Inspect the meaningful text, not just the title
A large opening title may look clear while smaller labels later in a video become difficult to read. Imagine a creator comparing several camera positions using arrows and short notes. The notes, not the title, carry the explanation. Identify the pieces of text necessary for understanding the subject and inspect those at your intended viewing size. This keeps a clear cover or introduction from masking a problem in the part of the presentation that actually matters to your task.
Choose a visually busy moment
The easiest frame may not reveal the real difficulty. In the camera-position example, look at a moment with an object, an arrow, and a label visible together. Can you connect the label to the correct object without repeatedly guessing? Notice whether the text competes with movement or background detail. The goal is not to invent a universal size rule from one sample, but to determine whether the particular composition remains understandable in the display you expect to use.
Consider reading time alongside size
Readable letters can still pass too quickly to be useful. Suppose three short instructions appear in sequence while the creator continues moving the camera. Try to understand both the text and the visual change at an ordinary viewing pace. If you need to stop repeatedly, describe which information is hard to combine. A longer display, a simpler instruction, or a separate explanation might help, but your review should report the observed issue before proposing a particular design solution.
Make a specific format request
For a custom piece, say which labels must remain legible in the intended small view and ask how the creator proposes to present them. In the camera-position example, you could prioritize the names of three positions over decorative introductory text. For an existing item, record whether the preview offers enough evidence to assess that requirement. The practical takeaway is to judge text where it does explanatory work, at the size and pace of actual viewing, rather than using a large-screen first impression.