Adobe Photoshop CS5 for Photographers - Martin Evening [39]
PDF versatility
The PDF format in Photoshop is particularly useful for sending Photoshop images to people who don't have Photoshop, but do have the Adobe Reader™ program on their computer. If they have a full version of Adobe Acrobat™ they will even be able to conduct a limited amount of editing, such as editing the contents of a text layer. Photoshop is also able to import or append any annotations that have been added via Adobe Acrobat.
Adobe PDF has now gained far wider acceptance as a reliable and compact method of supplying pages to printers, due to its color management features and ability to embed fonts, and compress images. It is now becoming the native format for Illustrator and other desktop publishing programs and is also gaining popularity for saving Photoshop files, because it can preserve everything that a Photoshop (PSD) file can. Adobe Reader™ and its predecessor Acrobat Reader™ are free, and can easily be downloaded from the Adobe website. But the full Adobe Acrobat™ program is required if you want to distill page documents into the PDF format and edit them on your computer.
Best of all, Acrobat documents are small in size and can be printed at high resolution. I can create a document in InDesign and export it as an Acrobat PDF using the Export command. Anyone who has installed the Adobe Reader program can open a PDF document I have created and see the layout just as I intended it to be seen, with the pictures in full color plus text displayed using the correct fonts. The Photoshop PDF file format can be used to save all Photoshop features, such as Layers, with either JPEG or lossless ZIP compression, and is backwards compatible in as much as it saves a flattened composite for viewing within programs that are unable to fully interpret the Photoshop CS5 layer information.
PDF security
The PDF security options allow you to restrict file access to authorized users only. This means that a password has to be entered before an image can be opened in either Adobe Reader, Acrobat or Photoshop. You can also introduce a secondary password for permission to print or modify the PDF file in Acrobat. Note: this level of security only applies when reading a file in a PDF reader program and you can only password protect the opening of a PDF file in a program like Photoshop. Once opened, it will then be fully editable. Even so, this is still a useful feature to have, since PDF security allows you to prevent some unauthorized, first level access to your images. There are two security options: 40-bit RC4 for lower-level security and compatibility with versions 3 and 4 of Acrobat; and 128-bit RC4, for higher security using Acrobat versions 5 or later. However, because the PDF specification is an open-source standard, some other PDF readers are able to bypass these security features and can quite easily open a password-protected image! The security features are not totally infallible, but marginally better than using no security at all.
Placing PDF files
The Photoshop Parser plug-in allows Photoshop to import any Adobe Illustrator, EPS or generic single/multi-page PDF file. Using File Place, you can select individual pages or ranges of pages from a generic PDF file, rasterize them and save them to a destination folder. You can also use File Place to extract all or individual image/vector graphic files contained within a PDF document as separate image files (see Figure 1.94).
Figure 1.94 If you try to open a generic Acrobat PDF from within Photoshop by choosing File Open, or File Place, you will see the Import PDF or Place PDF dialog shown here. This allows you to select individual or multiple pages, or selected images only and open these in Photoshop or place them within a new