Source Page

The Source Page section is where you clean up and adjust your imported PDF pages before imposition. You can rotate, flip, straighten, crop margins, apply image filters, and control bleed — everything you need to get your source material looking right.

The settings in this section apply to the page currently selected in the page strip. Both the Source Page box and the Filters box have link controls, so you can choose (for each settings group) whether this page shares settings with the rest of the document, the rest of its source PDF, or uses its own per-page settings.

Settings

Source Page

This box has a link control with three choices: document-linked, source-linked, or per-page.

Rotation

Rotates the source page in 90° increments. Choose from 0°, 90° CW (clockwise), 180°, or 270° CW.

Flip

Mirrors the source page. You can enable Horizontal and/or Vertical flipping independently using the checkboxes.

Straighten

A slider from -45° to +45° that lets you fine-tune the angle of the page — handy for scanned pages that went through a bit wonky.

This control is hidden when the content margins are set to Skew mode.

Content Margins

Controls which part of the source page to use. The mode radio buttons switche between two modes:

Rectangular — A visual margin editor with drag handles on each edge. Drag to crop the source page to the area you want. Use the Reset button to restore the full page. Rectangular margins support cropping and rotation, but assume your page is not skewed.
Skew — For scanned pages with perspective distortion. Drag the four corner handles to match the corners of the content on the page.

An Aspect Ratio slider lets you correct the aspect ratio of the de-skewed page, if the automatic setting does not give correct results. The aspect ratio controls are only visible in Skew mode.

When you’re working with skewed source pages, you can toggle between Source and De-skew Preview using the segmented control under the preview pane. You can only edit the locations of the skewed corners when in Source mode, but you’ll need to use De-skew Preview mode to see what the de-skew actually looks like. Additionally, the aspect ratio correction can only be previewed in De-skew Preview mode.

Bleed

Controls whether content is allowed to extend beyond the page margins into the bleed area. Choose from:

No bleed — Content stays within the margins.
Unconstrained bleed — Content can bleed as far as it extends.
Specify maximum bleed zone — Opens a visual editor where you set exactly how far the bleed can extend on each edge.

The visual editor appears only when Specify maximum bleed zone is selected. The entire bleed section is hidden when the content margins are in Skew mode.

Filters

This box has a link control with three choices: document-linked, source-linked, or per-page. Each filter has a checkbox to enable or disable it.

Levels

Adjusts the tonal range of the page. Enable the checkbox to apply a levels adjustment. When Levels is enabled, drag the three level adjustment handles (dark, mid and light) under the histogram to control the filter.

Monochrome

Converts the page to a single-channel image. When enabled, choose from one of three different filters:

Greyscale — A standard greyscale conversion.
Threshold — Converts to pure black and white with an adjustable cutoff (drag the handle on the histogram).
Adaptive — Converts to black and white using a local adaptive algorithm, with a Sensitivity slider to control the threshold. This is often the best choice for scanned text.

Denoise

Reduces noise in scanned images. When enabled, a Strength slider controls how aggressively noise is removed.

Unsharp Mask

Sharpens the page. When enabled, use the Amount slider to control the strength and the Radius slider to control the size of the sharpening effect.

Despeckle

Removes small speckles from scanned images. Enable the checkbox to apply.