Object Export options consolidate two major functions when exporting images to EPUB/HTML and Tagged PDF.
- The first function is the requirement to add and persist “alternative text” to placed images and graphics, which i’ll talk about in this post.
- The second function is the ability to create different conversion settings on each object, with special attention spent on settings useful for different screens sizes and pixel densities (ppi).
The dialog box has been made modeless, so that you can select different individual frames while leaving the dialog active.
The Object Export Options can be applied to both graphic and text frames, as well as to groups. You can also apply conversion options to text frames, which is very useful when you want to control the quality of rasterization applied to text effects like Drop Shadows, and Bevel and Emboss, in the exported HTML and EPUB files.
Object Export Options > Alt Text
Alternative text (or alt text for short) is a brief text based description of the subject captured in the photograph or illustration. Adding alt text is a common practice when creating HTML web pages and is also supported in EPUB and Tagged PDF. You can find information on writing Alt text at http://www.w3.org/QA/Tips/altAttribute. In InDesign CS5, do the following:
- Select an object and choose Object > Object Export Options > Alt Text.
- Choose one of the following
- From Structure: For legacy INDD files where users have already created all of the alt-text using the Structure Pane.
- From XMP (Title | Description | Headline ): Common XMP metadata fields used to capture some text about the image or graphic. If the XMP data is updated in another application like Adobe Bridge, updating the link in InDesign results in the alt text string being updated.
- From Other XMP: Only to be used by an XMP expert! Requires understanding the XMP path namespace and the array value. For example, the Bridge user interface supports IPTC Core, which contains a field titled “IPTC Subject Code”. If this was the field where Alt text string is stored, then in InDesign CS5.5, the value would have to be written as “Iptc4xmpCore:SubjectCode”. For advertuous mortals, in Photoshop, you can view the full namespace in an image under File Info > Raw Data.
- Custom: Users can enter their own custom alt text string. Useful when there is no pre-existing data, or when the metadata text is lacking in quality.
Besides this there are a few otherways Alt Text can be created in InDesign:
- From Microsoft Word: When you import a Word document with graphic images that have Alt Text already created in Word, these are converted to native InDesign alt text. Currently, only the Windows version of Word supports this feature.
- When a text frame has Object Export Settings for EPUB/HTML conversion to a graphic format like PNG, GIF, or JPEG, any alt text value is appropriately be passed through.