Confirm a caption track on the actual programme
Open the selected episode and inspect its available caption option. Track availability and visual styling are separate questions. Changing font size cannot create a track that is not supplied for the item being watched.
For a useful comparison, note the show, season and episode. If captions work on one episode but not another, retain that difference before changing the device’s global settings. It gives support a specific content case rather than only a general preference complaint.
Use the web route for web playback
The publisher describes a CC control in the web player, including appearance options such as size and colour. Open the current player controls and make one adjustment at a time so that the result remains understandable.
For example, if the problem is small text, increase size first and inspect an ordinary scene. If the problem is contrast, then compare an available colour or style setting. Altering every field at once can produce a new unwanted style without revealing which option helped.
Switch to the correct device instructions
Acorn publishes separate guidance for iPhone, iPad, Android, Fire TV, Apple TV and Roku. Some routes use platform caption preferences. Follow the current guide matching your actual device instead of searching for the desktop CC icon on a remote-controlled screen.
If the device route differs from the illustration, record its operating system and application version. Device generations and interfaces change. A missing control at an old pictured location is not proof that caption support has been removed from every version.
Preserve a readable result and a precise support note
After adjusting, check both dialogue and non-speech text where the selected track supplies it. Keep the preferred setting if it solves the viewing need. If it does not, describe whether the remaining problem is availability, size, colour, position or timing.
This article does not claim universal subtitle languages or a physical test of every Acorn TV app. It explains how to select the applicable official control path and compare the resulting presentation on the actual episode.
Questions about this guide
Can changing font size create absent captions?
No. Track availability and text appearance are different questions.
Should the desktop CC button be expected on every TV app?
No. Acorn provides device-specific instructions.