How to Flatten an InDesign Documentby Elle Smith ; Updated September 28, 2017
The InDesign software program included in Adobe's Creative Suite lets you create professional brochures, books, catalogs and other complex electronic documents for publication. One of the functions that can help the digital designer exercise precise control over graphic elements, color, typography and measurements is the use of layers. Layers are like sheets of paper stacked on top of the digital document, which appear to be on the same level. You can create and apply individual style changes to each layer, but the document quickly bulks up in size. You can flatten — or merge — the layers when the document is completed for ease of distribution or to prevent changes from being made to the document.
Flatten a Document
Open the InDesign document whose layers you want to flatten.
Select the "Layers" option in the "Window" menu to bring up the Layers palette.
Click all the layers in the palette to select them. This selects the source layers — or the layers that contain the images or items you want to flatten — as well as the target layer, which is the layer where you want all the objects to reside.
Click the small drill-down arrow to the left of the Layers palette. Click "Merge Layers."
Flatten Individual Spreads
Open the document that contains the page spread.
Click "Pages" from the "Window" menu.
Click the small drill-down arrow to the left of the page layout thumbnails, then scroll to "Spread Flattening." Scroll to the submenu, and choose an option. Select "Default" to use the program's flattening presets. Select "None" to ignore the transparency values in the document. Select "Custom" to specify custom flattening settings. In this option, enter a value in the "Raster/Vector Balance" text field; select line art and text resolution; enter a value for gradient and mesh resolution; or convert text and strokes to outlines or to clip complex areas.