How to make your videos accessible: captions, alt text and contrast

A lot of people can't fully experience your content the way you made it. Some are Deaf or hard of hearing. Some are blind or have low vision. Some have trouble processing fast audio, or speak your language as a second language. And a huge number are just scrolling on a bus with the sound off.

Making your content accessible isn't a big production. It's mostly a handful of habits: caption your videos properly, describe your images, make your text readable, and avoid a few effects that cause real harm. Each one also tends to make your content clearer for everyone.

Why it's worth doing

• More people can actually watch. Anyone who can't hear or see part of your post is effectively shut out of it.
• Sound-off viewers stay. Plenty of people watch with no audio. Captions are what keep them watching.
• Clarity improves. Clear text, good contrast and spoken descriptions make content easier for everyone to follow.
• Search can read it. Captions and written descriptions give platforms more text to understand what your post is about.
• Brands notice. More companies care about accessibility in the content they sponsor, and some ask for captions as a deliverable.

Captions: the biggest single win

If you do only one thing from this guide, caption every video that has speech in it.

Closed captions vs burned-in captions

Type	What it is	Pros	Cons
Closed captions	A separate text track viewers can turn on or off	Can be resized or styled by the viewer on some platforms, readable by assistive tech	Not every platform or upload flow supports them
Open (burned-in) captions	Text that's part of the video image	Always visible, you control the look	Can't be turned off, can't be read by screen readers, can clash with platform buttons

Many creators use the platform's caption tool (which usually creates closed captions or caption stickers) for short videos, and upload a proper caption file for long YouTube videos. Either is far better than nothing.

Auto captions are a first draft

Auto-generated captions have improved a lot, but they still get names, slang, brand names and technical terms wrong, and they often miss punctuation entirely. A wrong caption can be worse than none: "you can now pause it" and "you can't now pause it" read very differently.

Always review auto captions before posting. On a 30 second video, that's a minute of work.

What good captions look like

• Accurate. The words match what's said. Fix names, numbers and terms.
• In sync. Text appears when the words are spoken, not a second later.
• Short lines. One or two lines on screen at a time, broken at natural pauses.
• Readable size. Big enough to read on a phone at arm's length.
• High contrast. White or yellow text with a dark outline or a solid background behind it.
• Out of the way. Not covered by the platform's buttons, captions or progress bar. Keep text inside the safe area in the middle of the frame.
• Include important sounds. If a sound matters to the story, caption it: [doorbell rings], [laughter], [upbeat music].
• Identify speakers. If more than one person talks, make clear who's speaking, with names or positioning.

Don't caption-dump

Some creators burn in captions that appear one word at a time, bouncing, changing color and size with every word. It can look energetic, but it's harder to read, especially for people who rely on captions. If you use animated captions, keep the motion gentle and show whole phrases, not single words flashing past.

Captions for long videos

For YouTube and other long videos, uploading a proper caption file (like an SRT) gives the best result. You can export one from most editing apps or caption tools. Check it the same way you'd check auto captions: names, terms, timing.

Alt text: describing images for people who can't see them

Alt text is a written description attached to an image. Screen readers read it out loud for blind and low vision users. Many platforms let you add it, either automatically or in an advanced or accessibility setting when you upload. At the time of writing, places to look include the accessibility or advanced settings on Instagram and Facebook uploads, the description option on X, Bluesky and Mastodon image uploads, and the alt text field on Pinterest and LinkedIn. Platforms move these settings around, so if you can't find it, search the help center for "alt text".

Platforms often generate automatic alt text too. It tends to be very generic ("Image may contain: one person, indoor"). Write your own whenever you can.

How to write useful alt text

Ask yourself: if someone couldn't see this image, what would they need to know to get the same thing out of the post?

• Describe what matters, not everything. Focus on the content and the point of the image.
• Be specific. "A sourdough loaf with a deep golden crust and an open, airy crumb" beats "bread".
• Include any text in the image. If your graphic says "5 mistakes beginners make", the alt text needs to say so. Screen readers can't read text that's baked into an image.
• Keep it concise. A sentence or two for most images. Longer for detailed infographics.
• Skip "image of" or "picture of". Screen readers usually announce it's an image already.
• Don't stuff keywords. It's for people, not search.

Examples

Post	Weak alt text	Better alt text
Recipe photo	"Food"	"A bowl of red lentil soup topped with yogurt, chili oil and fresh cilantro, with torn flatbread on the side"
Before and after	"Room makeover"	"Before: a cluttered bedroom with clothes on the floor. After: the same room with a made bed, clear floor and plants on the windowsill"
Quote graphic	"Quote"	"Text on a beige background reads: Done is better than perfect. Just keep posting."
Product shot	"My new camera"	"A compact mirrorless camera with a small prime lens, sitting on a wooden desk next to a notebook"
Carousel slide with tips	"Tips"	"Slide 2 of 6. Tip 1: shoot near a window. A phone on a stand facing a bright window"

Carousels and infographics

Each slide needs its own description, especially if slides contain text. For text-heavy graphics, consider putting the key points in your caption too, so the information is available to everyone regardless of how they access it.

Contrast: text people can actually read

Light gray text on a white background looks sleek and is hard to read for a lot of people, especially on a phone in sunlight.

The Web Content Accessibility Guidelines (WCAG), the widely used standard for digital accessibility, recommend a contrast ratio of at least 4.5 to 1 for normal text and 3 to 1 for large text. You don't need to measure every graphic, but it's a useful benchmark. Free contrast checker tools let you paste two colors and see the ratio.

Practical rules for on-screen text

• Dark text on light, or light text on dark. Avoid mid-tones on mid-tones.
• Add a background or outline on video. Video backgrounds change constantly. A semi-transparent dark box behind white text keeps it readable on any frame.
• Avoid red and green as the only difference. Color blindness commonly affects telling these apart. If you're showing "good vs bad", add a label, an icon or a check and a cross.
• Use simple fonts for important text. Decorative or thin script fonts are hard to read quickly.
• Make it big enough. If you have to squint at it on your own phone, it's too small.
• Leave it on screen long enough. A common rule of thumb is long enough to read it twice at a normal pace.

Hashtags, emoji and screen readers

Screen readers read text literally, which affects a few habits most creators never think about.

Capitalize each word in hashtags

Write #SourdoughForBeginners, not #sourdoughforbeginners. Capitalizing each word (sometimes called camel case) helps screen readers read the words separately and makes the tag easier for everyone to read. Platforms treat hashtags the same regardless of capitalization, so there's no downside.

Go easy on emoji

Screen readers read emoji by their names. A caption with a row of ten fire emoji gets read out as "fire" ten times. Some tips:

• Use emoji to add meaning, not to replace words.
• Put emoji at the end of a sentence rather than in the middle.
• Avoid long strings of repeated emoji.
• Don't use emoji as bullet points for important lists.

Skip fancy text generators

Those "stylish font" generators that make bold or cursive text in bios and captions use special mathematical and symbol characters. Screen readers often read them out letter by letter, or skip them entirely. Your fancy name might be read as a string of symbols. Use plain text.

Flashing and motion: avoid causing harm

Rapid flashing can trigger seizures in people with photosensitive epilepsy. This is the one accessibility issue that can cause physical harm, so take it seriously.

• Avoid content that flashes more than three times per second. That's the threshold WCAG uses. Strobe effects, rapid flicker transitions and fast-flashing lights are the usual culprits.
• Be careful with big, bright red flashes, which are considered higher risk.
• Add a warning at the very start if a video must include flashing lights (for example, footage from a concert). Put it in the first frame and in the caption, before the flashing starts.
• Go gentle on shaky zooms and spinning transitions. Heavy motion effects can cause dizziness or nausea for some viewers.

Describe what you're showing

For blind and low vision viewers, a video where you silently point at things is hard to follow. Narration fixes most of it.

• Say what you're doing. "Now I'm folding the dough over itself, like closing a book" instead of "now do this."
• Read out important on-screen text, or make sure it's also in your caption.
• Describe visual punchlines when they matter to the point.

You don't have to narrate every frame. Just make sure the key information isn't only visual.

Make your language easy to follow

• Speak clearly and not too fast, especially for key points.
• Use plain words. Explain jargon when you have to use it.
• Put key information in writing too. Steps, links, ingredient lists and dates should be in the caption or description, not only spoken in the video.
• Structure long captions with line breaks and short paragraphs.

A quick accessibility checklist

Before you post, run through this:

• Captions on, and checked for names, numbers and terms?
• Captions readable: size, contrast, not hidden behind buttons?
• Important sounds captioned?
• Alt text written for every image and carousel slide?
• Text in images also described in alt text or caption?
• On-screen text has good contrast and stays up long enough?
• Hashtags capitalized, emoji used lightly, no fancy fonts?
• No flashing over three times per second, or a warning at the start?
• Key visual steps described out loud?

It feels like a lot the first time. After a couple of weeks, it's automatic.

The short version

• Caption every video with speech, and always correct auto captions.
• Write your own alt text for images: describe what matters and include any text in the image.
• Keep on-screen text high contrast, large, and on screen long enough to read.
• Capitalize each word in hashtags, use emoji lightly, and avoid fancy font generators.
• Never post rapid flashing without a warning, and keep heavy motion effects gentle.
• Narrate what you're doing and put key info in writing.

Accessibility is a habit, not a project. Bake the checklist into how you post, and some scheduling tools (Vantr included) let you add alt text to images while you're preparing the post, so it isn't an afterthought at publish time.