Little-known PowerPoint feature generates high-res images

A concealed feature of PowerPoint 2003 can be used to create high-resolution images for radiology journal publications, according to researchers at Beth Israel Deaconess Medical Center.

Exported images in older versions of PowerPoint - including 97, 2000, and XP - were limited to the computer screen resolution, usually 72 or 96 dots per inch. PowerPoint 2003, on the other hand, allows users to customize image resolution to higher values, said Chun-Shan Yam, Ph.D., of the radiology department at Beth Israel.

This feature is obscure because no entry for it appears in the file menu, and it is not documented in the Windows help menu. Detailed instructions are available on Microsoft's Web site.

The feature is optional, however, and Microsoft's default setting for image export is configured at the low-resolution 72 or 96 dpi setting. Radiology journals typically require a print-quality resolution of at least 300 dpi.

"To enable high resolution, users must add an optional registry parameter at the system registry file (i.e., ExportBitmapResolution) to specify output image resolution," Yam said.

This process is documented on Microsoft's support pages or in Yam's paper, published in the July issue of the American Journal of Roentgenology.

Although this feature is adequate for generating images for journal publication, other radiology applications that require higher resolution images and more complex graphics may require more sophisticated software, such as Adobe Photoshop, according to Yam.

Also, the images exported from PowerPoint 2003 will be in red-green-blue (RGB) format, not cyan-magenta-yellow-black (CMYK) or gray-scale format.

"Although some journals such as Radiology and RadioGraphics require image files to be submitted in RGB or CMYK for final prints, they accept images in RGB format provided image resolution meets requirements," he said.

PowerPoint 2003 has been available since May, 2003, and is included in Microsoft Office 2003. Microsoft has announced that the high-resolution feature will be available for all future PowerPoint versions. The feature is also available for Macintosh computers in the latest Microsoft Office versions (Office 2001 and X).

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