Visibility and printing

An item is drawn only when its layer is both Visible and Printable; everything else a layer records is ignored at render time.

In short: Of all the switches a layer carries, only two change the renderer's output: Visible and Printable. An item is painted only if the layer its ItemLayer names is both visible and printable — either one turned off drops the item, and both default to on. Locked is read but never affects what is drawn, and nested layer folders are flattened to a single peer list. This page explains exactly when content is suppressed, and is equally clear about the layer attributes that look like they should matter but do not.

Of everything a layer records, only two switches change what comes out of the renderer: Visible and Printable. They are the reason layers are worth documenting before the rest of the layer model — get these two wrong in a fixture and content silently vanishes. This page explains exactly when that happens, and is equally clear about the layer attributes that look like they should matter but do not.

One test, two switches

When the renderer walks a spread, every page item is checked against the layer its ItemLayer names. The rule is a single AND: an item is drawn only if its layer is both visible and printable. Either switch turned off is enough to drop the item.

• Visible="false" — the layer is hidden. None of its items are drawn.
• Printable="false" — the layer is marked non-printing. The current renderer treats this the same as hidden: its items are suppressed from output.

Both default to on. A layer that omits Visible is visible; a layer that omits Printable prints. And an item whose ItemLayer is missing, or which names a layer that is not defined, is also drawn — the renderer only suppresses an item when it can resolve ItemLayer to a real layer that is explicitly off. A missing or dangling reference never makes content disappear by accident.

Because the two switches collapse into one decision, the renderer precomputes a single visible && printable answer per layer before it starts painting, then consults that one flag for each item. There is no separate "printing pass" today — on-screen and to-output are the same suppression.

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<?aid style="50" type="document" readerVersion="6.0" featureSet="257" product="20.0(32)"?>
<Document xmlns:idPkg="http://ns.adobe.com/AdobeInDesign/idml/1.0/packaging" DOMVersion="20.0" Self="d" StoryList="ustory" Name="layer-visibility.indd" CMYKProfile="Coated FOGRA39 (ISO 12647-2:2004)" RGBProfile="sRGB IEC61966-2.1" SolidColorIntent="UseColorSettings" AfterBlendingIntent="UseColorSettings" DefaultImageIntent="UseColorSettings">
  <Layer Self="ulayer-front" Name="Front" Visible="true" Locked="false" Printable="true"/>
  <Layer Self="ulayer-back" Name="Back" Visible="false" Locked="false" Printable="true"/>
  <idPkg:Graphic src="Resources/Graphic.xml"/>
  <idPkg:Fonts src="Resources/Fonts.xml"/>
  <idPkg:Styles src="Resources/Styles.xml"/>
  <idPkg:Preferences src="Resources/Preferences.xml"/>
  <idPkg:Tags src="XML/Tags.xml"/>
  <idPkg:MasterSpread src="MasterSpreads/MasterSpread_umaster.xml"/>
  <idPkg:Spread src="Spreads/Spread_uspread.xml"/>
  <idPkg:Story src="Stories/Story_ustory.xml"/>
  <idPkg:BackingStory src="XML/BackingStory.xml"/>
</Document>

The example makes the parse-versus-render distinction concrete. Inspecting the package, the spread reports two rectangles — both are well-formed and the parser builds both. But the rendered page reports a single frame and a single paint command: the rectangle on the hidden layer is gone by the time the page is drawn. "It is in the XML" and "it is on the page" are two different statements, and the layer's switches are what separate them.

Locked is read, but the renderer ignores it

A layer can also be marked Locked. In an editor, locking a layer stops you from selecting or moving the items on it — it is a guard against accidental edits. The parser reads Locked and keeps it on the layer model, but it has no bearing on output: a locked layer renders exactly like an unlocked one. Locking is an authoring-time concern that belongs to a canvas and its selection logic, not to a renderer that only draws.

So if you are reading an IDML to understand what a page looks like, you can ignore Locked entirely. It matters only to tools that let a user push the pixels around.

Layer folders are flattened

InDesign's Layers panel can nest layers inside layer groups (folders) for tidiness. That nesting is purely organizational, and the model here does not carry it: layers are kept as a single flat, ordered list, with no parent/child relationship between them. Every <Layer> is a peer. In practice this costs nothing for rendering — a folder never affected whether its layers' items draw, only how they were grouped in the panel — but it does mean you cannot ask this model "which folder is this layer in." There is no folder to ask about.

What to check when content goes missing

The practical payoff of this page is a short checklist. When a frame you can see in the spread XML does not appear on the rendered page, and the geometry looks fine, walk the layer link:

1. Read the item's ItemLayer to find which layer it claims.
2. Find that <Layer> in designmap.xml.
3. Check its Visible and Printable. If either is false, that is your answer.

If the item has no ItemLayer, or it points at a layer that is not in the design map, layers are not your problem — the renderer would have drawn it on the default layer, so the disappearance is something else (geometry, color, or threading).

Frequently asked questions

When is a page item's layer allowed to keep it off the page? An item is drawn only when its layer is both Visible and Printable. Either switch set to false is enough to suppress the item; both must be on (their default) for it to paint.

Does Printable="false" behave differently from Visible="false"? Not in the current renderer. There is no separate printing pass: on-screen and to-output are the same suppression, so a non-printing layer hides its items exactly as a non-visible one does. The renderer precomputes a single visible && printable flag per layer and consults that.

Does a Locked layer affect the rendered output? No. Locked is read into the layer model but never changes what is drawn — a locked layer renders exactly like an unlocked one. Locking is an authoring-time guard against accidental edits, a concern for an editor's selection logic, not for a renderer.

Are nested layer folders (layer groups) preserved? No. InDesign's layer groups are purely organizational, so the model flattens them to a single ordered list of peer layers with no parent/child relationship. This costs nothing at render time — a folder never affected whether its layers' items drew — but the model cannot tell you which folder a layer was in, because no folder is retained.