When to choose WMF, EMF or EMF+ format

Last modified May 4, 2015

When copying an image to the clipboard, Prism Windows can use three related vector and font based formats: Windows Metafile (.WMF), enhanced metafile (.EMF, which Prism calles "EMF(old) ) and the newer extended metafile (EMF+) format. All these files contain vector and font instructions for how to draw the graph. This means you can resize the image (in another program) with no loss of quality. These formats are only used by Windows program, not Mac programs (so Prism Mac cannot export in these formats).

Up through Prism 4.00, WMF was the only format provided. Prism 4.01 added support for EMF, and Prism 6.00 added support for EMF+. When exporting, choose the format in the export dialog (where you'll have other choices too). Before copying to the clipboard, choose the desired format in the File&Printer tab of the Preferences dialog. 

WMF is an ancient format; EMF is old, and EMF+ is the newest. So generally EMF+ is the best format. But not always. You may need to experiment to see which format works best for your needs, but these notes may help you choose:

  • This choice matters only when you copy/paste a graph or layout to another program, or send the graph or layout directly to Word or PowerPoint. This choice does not affect how Prism files are stored. 
  • Don't use WMF when exporting or pasting bar graphs with fill  patterns to PowerPoint. If you use WMF, the patterns on such a graphs do not scale and appear of higher density.  
  • We've heard reports that colors will change (when you close then reopen the PowerPoint file) when EMF images are pasted into PowerPoint, but not with WMF (or EMF+).
  • Choose EMF(old) instead of "EMF+" to workaround the problem with somewhat corrupted graph when pasting EMF+ to older versions of Adobe Illustrator (CS5) or Corel draw. The problem is how Adobe Illustrator opens "EMF+" format that is generated by GDI+ in Prism 6.  
  • Choose EMF(old) instead of "EMF+" to when a graph is sent to Word, PowerPoint or Excel and then exported to PDF. With EMF+, the fonts can change. 
  • Some very old programs do not support EMF. For these choose WMF.
  • EMF(old) and EMF+ files exported by Prism 7 encode transparent colors, but WMF files do not encode transparency. If you choose any transparent colors when making your graph, it won't look transparent in the exported file if you choose WMF.
  • EMF+ can encode semitransparent colros, but EMF(old) cannot.
  • EMF+ is a newer format than EMF but both kinds of files use the same .EMF extension. Prism refers to "EMF(old)" and  "EMF+", but these abbreviations are not standard.
  • Some programs can display images in EMF+ format much more quickly than they can display images in EMF(old) format. 

Bottom line. On macs, graphs and layouts are copied as pdf and it just works. On Windows, there is a choice of three related formats, and there are pros and cons and glitches with each. The notes above may help. But you may need to experiment depending on what you plan to do after you paste the graph or layout. 


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