Putting numbers on screen honestly

Why data on video is different

A chart in a document can be studied. A chart in a video is on screen for four seconds, cannot be paused by most viewers, and has to be understood while somebody is talking over it.

That constraint changes what is possible. Most charts that work on a page do not work on video, and the failure is not aesthetic — the viewer simply does not extract the number.

One number per graphic

The reliable rule. If a graphic is on screen for four seconds, it can carry one comparison.

"Sales rose" — one line, two labelled endpoints. Not twelve series, not a legend, not axis ticks at every interval. Anything the viewer has to decode is time they are not spending on the point.

If you genuinely have five things to say about the data, that is five graphics, revealed in sequence, not one graphic with five things in it.

Reveal, do not present

Animation earns its place here, for a specific reason: a chart that draws itself directs attention in time. The bar grows, so the viewer watches the bar. A static chart appears complete and the eye wanders.

Useful patterns:

• Bars grow from the baseline, eased, over 10–20 frames, staggered by 2–3 frames each.
• A line draws left to right at roughly reading speed.
• The label appears after its bar or point has settled, not with it.
• The one that matters is highlighted by colour after the rest have drawn.

All of these are keyframed scale, position and opacity — the techniques from earlier in this block. None needs a specialist tool.

Legibility

The same constraints as all video type, applied to charts:

• Label directly on the element. A legend forces a lookup, and a lookup takes a second you do not have. Put "2024" at the end of its line.
• Bold weights only. Axis labels in a light weight will not survive compression.
• Few gridlines, or none. Thin grey lines at 1 px are precisely what the encoder discards.
• Round the numbers. "₹3.2 crore" is read; "₹32,147,882" is not.
• Do not rely on colour alone to distinguish series. Around one in twelve men has some degree of colour vision deficiency, and a red-against-green comparison is exactly the common case. Use position, labels or pattern as well.

Honesty

The same obligations as anywhere else, with the added difficulty that a video viewer cannot go back and check.

Start bar charts at zero. A truncated axis makes a 3% difference look like a doubling. On a page a reader might notice the axis label; in four seconds of video they will not.

Do not use area or volume to represent a single quantity. Doubling a circle's diameter quadruples its area, and the viewer reads area. If you scale an icon by value, scale it by area, not by height.

Say the denominator. "Complaints up 40%" means something different if the number went from 5 to 7.

Label the source and the date on screen, in small type. It takes one line and it is the difference between a claim and a citation.

Do not animate between two scales. A bar that grows while its axis also changes is telling the viewer nothing they can read.

The general principle: on video, the viewer's only defence against a misleading chart is you not making one. The usual excuses — it was in the source, the axis was labelled — do not apply when the graphic is on screen for four seconds under a voice-over.

Building them free

In the editor: a bar chart is rectangles with animated scale. For three or four bars this is genuinely the fastest route and gives you complete control.

Inkscape: draw the chart properly, export layers as PNGs, animate the layers in the editor.

A browser: HTML and CSS, or a charting library, recorded or rendered to PNGs. The right answer when the data changes or there are many charts.

Python with matplotlib: free, and it will render a sequence of PNGs directly, which is the most reproducible route for anything data-driven. Save with a transparent background and composite in the editor:

plt.savefig(f"frames/chart_{i:04d}.png", transparent=True, dpi=200)

Spreadsheet exports: LibreOffice Calc will produce a chart you can export as an image. Usable, and it will look like a spreadsheet chart, which is sometimes exactly right for a business context.

Today

Take a chart from a document and redraw it for four seconds of screen time: one comparison, labels on the elements, numbers rounded, source in the corner. Compare the two.