Binary FX: Photoshop Tech Vault 3.0

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Create a PostScript Clipping Path

How To:

Create a PostScript clipping path.

Manual tracing with the pen tool is often the preferred way to produce quality clipping paths, although Adobe offer an assistant/wizard to walk new users through the process of creating a clipping path, found under the help menu.

Avoiding Common Clipping Path Problems:

Old habits die hard, and long term users may start drawing with the pen tool without first checking the options bar settings. As older versions of Photoshop did not have path options, clipping was always a simple task. This is no longer the case. When a regular path is required, ensure that the path option icon is selected (illustrated below, left hand side). The exclude overlapping path areas option (illustrated below, right hand side) was not explicitly known in earlier versions, although that is the type of path behaviour that most users are familiar with. This is the critical option that is the major source of contention for many users who complain of unexpected clipping path behaviour such as compound paths not working correctly.

Path & Exclude Overlapping Path Areas Options: A GIF animation of the two common options which may not be active when constructing clipping paths with the pen tool in Photoshop v6 or higher. Enabling these two options resolves the two common issues users commonly have with path construction in later versions.

Altering Existing Path Behaviour:

If an existing path has the incorrect options applied, the path selection tool [A] is used to select the entire clipping path (main and sub paths). This selection is indicated via solid anchor points. Next the exclude overlapping path areas option is selected. This will return legacy behaviour to selections in Photoshop or clipping output in other software.

Clipping Path Options:

The initial step when constructing paths is to first save them as a regular path from the default temporary work path. As it is possible to have more than one path in a document, the Clipping Path option must be applied to one of the possible paths in the file. Flatness is found under the paths palette options menu under the clipping path option. Flatness is used to describe how smooth a curve is when imaged to a PostScript interpreter (RIP). Ideally this field is left blank so that the default output device value is applied when printing. This option is probably best used for trouble shooting if problems are encountered at output.

Further Information:

Clipping paths are not suited to all image content, which is one reason why current versions of Adobe illustration and layout software can accept Photoshop layer transparency without the need for a clipping path. This step requires flattening at some stage prior to output, which can be a complex subject when it comes to final print production. Thus, producing accurate and problem free clipping paths is still an important issue for many users. It is often critical to ensure that clipping paths are set to the exclude overlapping path areas option. Creating a clipping path may be known by regional terms such as deep etching, close cropping, or clear cutting. To avoid confusion with Photoshop terms such as cropping or creating raster based transparency such as Photoshop layer transparency, if a clipping path is required it is best to use the term clipping path.

Pen Tool Preset:

Users of Photoshop 7 or later may prefer to set a tool preset for the pen tool which defaults to the path and exclude overlapping path areas options as illustrated above:

Download the 1KB .tpl file .zip archive for: Photoshop 7 or later

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