§9.6.4

Color as the Value

A cell whose only content is a colour—what goes in it?

✅ NormativeSettled. The requirement holds as written.📄 Page ruleCan be applied from the page alone.Read §9.6.4 in the RFC ↗

The requirement

A cell whose only content is a coloured fill MUST be rendered as an empty  carrying the colour: <td></td>. The colour MUST be the nearest HTML colour name, never the meaning a legend assigns it, and the cell MUST NOT be left blank.

When it applies

Risk matrices and heatmap tables put the meaning in the fill. The cell has no text at all:

Sketch of the printed page — layout, not output

| Likelihood ╲ Impact | Low | High |
| Rare                | 🟩  | 🟨   |   ← the fill IS the value
| Likely              | 🟨  | 🟥   |

Read straight through, the body of that table is blank, and a blank body makes the whole grid meaningless.

Reading the examples. Each one pairs a source page with the output the rule expects. ✅ Sample: the rule applies. ❌ Counter-sample: it looks like it applies and does not, or a rendering got it wrong. A non-conforming output, in red, is shown only for contrast. … marks content left out of an excerpt.

The rendering

<tr>
  <td>Rare</td>
  <td><mark style="background-color: green"></mark></td>
  <td><mark style="background-color: yellow"></mark></td>
</tr>

The  MUST be empty: the cell prints no text, and adding some would be inventing content.
The colour rides on the style attribute — the same mechanism as highlighted text in Highlighted Text (§7.2.5) and Text Formatting Conventions (§7.1). One vocabulary covers both: the nearest HTML colour name in style="background-color: …".
The colour MUST NOT be written as the cell's text. A cell reading green is indistinguishable from a cell whose printed content is the word "green" — and heatmap legends do sometimes spell their colours out. Text is what the page printed; the attribute is how the cell was filled.

The rendering degrades correctly. A consumer that ignores attributes sees an empty cell, which is truthful — the page printed no text there. A consumer that reads them gets the value. Neither is misled.

Why not the meaning

Writing "Low risk" instead of "green" means reading a legend, and the legend is routinely elsewhere on the page or on another page entirely. A rendering that depends on material outside the region would be a guess whenever that material is out of reach. The colour name needs no legend, stays faithful to the page, and leaves the interpretation to whoever reads the table.

Colour that is not the value

The two cases MUST be kept apart:

The cell prints	Rendering
A fill and text	The text is the value; the fill is decoration or revision tracking. The text is transcribed and the fill is not carried.
A fill and nothing else	The case of this rule: an empty `<mark>` with the fill's colour.

❌ Counter-sampleLooks like it applies and does not — or a rendering got it wrong

Cells carry a yellow fill and printed numbers`yellow`

Cells carry a yellow fill and printed numbers — decoration layered over real content, not a colour-only cell, so only the text is rendered. The lettered rows are indented under their numbered parents, while dividends under (5) Preferred stock is printed flush left; Sum of line (1) thru (9) is the total row, indented under (10) Total; each column heading is one wrapped label.