Color & swatches

In an IDML document, color lives in one shared palette — every fill and stroke just points at it by name.

In short: An IDML document keeps all of its color in a single part, Resources/Graphic.xml — a flat palette of named colors, gradients, and tints. Nothing on a page carries its own raw channel values; a rectangle, a run of text, or a frame border simply names a swatch by id, and the swatch holds the actual color. That one indirection is the whole idea: change a swatch once and everything that references it follows. This chapter explains how that palette is built, how a fill resolves to a real color, and where Paged's renderer is faithful or still approximate.

Every visible fill and stroke in an IDML document points at the palette: a shared table of named colors, gradients, and tints that lives in one part, Resources/Graphic.xml. Nothing on a page carries its own raw color. A rectangle, a piece of text, a frame border — each names a swatch by id, and the swatch holds the actual channel values. Change the swatch once and everything that references it moves with it.

This is why color is a cross-cutting chapter rather than a property of any one element. The same Color/Red can fill a rectangle, tint a run of text, and seed a gradient stop. The reference parts that describe shapes and text take the palette as given; this chapter is where the palette itself is defined.

The palette is a small set of element kinds

Resources/Graphic.xml is a flat list. The parser walks it once and keys what it finds by each element's Self id, so a later FillColor="Color/Red" is a direct lookup. Four kinds matter for rendering:

• <Color> — a single color in one of four spaces (CMYK, RGB, Lab, Gray), marked either Process or Spot. The workhorse of the palette.
• <Swatch> — a thin named wrapper. The reserved "None" swatch is one; most others just point at a <Color>.
• <Gradient> — a blend between two or more stops, each of which references a <Color>. A gradient owns no color of its own.
• tints — "this color at N%". Tint shows up two ways: as a swatch-level value on a spot <Color>, and as a per-use FillTint on the thing being painted.

A handful of other constructs — mixed inks, mixed-ink groups, and color groups — are part of the format and the parser reads them, but the renderer does not yet give them their full meaning. Those gaps are called out where they belong rather than hidden.

How a fill resolves

When a shape says FillColor="Color/Red", the renderer looks Color/Red up in the palette. If the id names a <Color>, it converts that color's channel values to device color for display. If it names a <Gradient>, the renderer resolves each stop's referenced color and builds a gradient paint. If it names a <Swatch> such as Swatch/None, that is the explicit "no fill" case. The id is the contract; the palette is the source of truth.

The example below is the smallest version of that story: one new <Color>, applied to one rectangle.

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<idPkg:Graphic xmlns:idPkg="http://ns.adobe.com/AdobeInDesign/idml/1.0/packaging" DOMVersion="20.0">
  <Color Self="Color/Black" Model="Process" Space="CMYK" ColorValue="0 0 0 100" ColorOverride="Specialblack" Name="Black" ColorEditable="false" ColorRemovable="false" Visible="true"/>
  <Color Self="Color/Paper" Model="Process" Space="CMYK" ColorValue="0 0 0 0" ColorOverride="Specialpaper" Name="Paper" ColorEditable="true" ColorRemovable="false" Visible="true"/>
  <Color Self="Color/Red" Model="Process" Space="CMYK" ColorValue="0 100 100 0" ColorOverride="Normal" Name="Red" ColorEditable="true" ColorRemovable="true" Visible="true"/>
</idPkg:Graphic>

Where to go next

• Colors & swatches — the <Color> and <Swatch> attributes, the reserved built-ins, and what each space means.
• Gradients & tints — <Gradient>, <GradientStop>, and the two ways a tint reaches a color.
• Spot & process color — why spot inks are previewed through a CMYK alternate, how ICC conversion fits in, and the honest edges of what the renderer reproduces.

The ordering here follows a reader building up from a flat color to gradients to the press-oriented spot/process distinction — not the source spec's section order (clean-room §6.1).

Frequently asked questions

Where does an IDML document store its colors? All of them live in one part, Resources/Graphic.xml, as a flat palette of <Color>, <Swatch>, and <Gradient> entries. The pages and shapes themselves hold no channel values — they reference palette entries by their Self id.

How does a shape's fill turn into an actual color? A shape names a swatch in its FillColor (or StrokeColor), and the renderer looks that id up in the palette. If it resolves to a <Color>, the channel values are converted to device color; if it resolves to a <Gradient>, each stop's referenced color is resolved and a gradient paint is built; if it resolves to Swatch/None, that is the explicit "no fill" case.

Why is color a separate chapter rather than part of shapes or text? Because the palette is cross-cutting: the same Color/Red can fill a rectangle, tint a run of text, and seed a gradient stop. The parts that describe shapes and text take the palette as given, so it makes sense to define the palette itself once, in its own place.