EPS graphics with Akustyk and Praat

What is EPS?

(EPS) An extension of the PostScript graphics file format developed by Adobe Systems. EPS is used for PostScript graphics files that are to be incorporated into other documents. An EPS file includes pragmas (special PostScript comments) giving information such as the bounding box, page number and fonts used. PostScript is an unusually powerful printer language because it is a full programming language, rather than a series of low-level escape sequences. For years PostScript has been the industry standard for graphical output. One of the main advantages of EPS files is that they are relatively small in size, as they contain instructions sent to the printer, rather than pixel information. Images that contain pixel information are called bitmaps. EPS graphics are resolution-independent, which makes them ideal for high quality output for graphs, charts, and plots.

Using graphics created by Akustyk and Praat.

Praat picture file

Praat can store any graphical object created by the Praat picture module. It is a good idea to save all of your images as Praat picture files. You will always be able to open them in Praat and modify, if necessary. To save a Praat picture file:

1. create a graphic object
2. select it by clicking and dragging (the pink border in MS Windows)
3. choose File, Write to praat picture file...
4. save the file as "filename.prapic"

Screen resolution

It is possible to save a Praat image directly to the clipboard (Ctrl C) or take a screen shot of the image. However, this technique will only let you rasterize such images at the typical screen resolution of 72 dpi. While such images look fine on a computer screen, their resolution is not high enough to use them in print.

The images below show a fragment of a Praat-generated image at the 400x magnification. The bitmap image (left) shows significant degradation, while the EPS image (right) offers unchanged resolution throughout.

Save as EPS

The Praat picture format can only be opened with Praat. EPS is certainly the best distribution format for your graphics. To create an EPS image:

1. create a graphic object
2. select it by clicking and dragging (the pink border on MS Windows)
3. choose File, Write to EPS file...
4. save the file as "filename.eps"

Using EPS graphics in print

If you have a PostScript compatible printer

Since PostScrip is a technology designed for print, EPS graphics created by Akustyk and Praat are ready for print. There is no need to rasterize them (convert them to a bitmap). However, you need to print those images on a PostScript compatible printer. Fortunately, most laser printers these days support PostScript. Chances are that the networked printers at your school or office will be PostScript compatible. Also, Microsoft Word (2000 and 2003), which is the most popular word processing software, comes equipped with a PostScript import filter. You can simply insert your EPS images into MS Word. Follow these steps:

1. open MS Word
2. place the cursor where you want to insert your image
3. go Insert, Picture, From file
4. locate your image on your hard drive
5. you're done

The image will appear jagged and many of the phonetic symbols will not look correct. However, this is no reason to worry. In fact, your image will appear razor-sharp once you print it on a PostScript compatible printer. Note that you can also resize the image (and make other simple modifications) in MS Word by double-clicking on the inserted EPS graphic and clicking on the "Resize" tab. It is best to check "Lock aspect ratio" before resizing.

If you don't have a PostScript compatible printer.

Convert to PDF in MS Windows

If you do not have a PostScript compatible printer, you may still insert EPS images into MS Word, but you will have to convert your MS Word document before printing. Adobe Distiller, which is part of the Adobe Acrobat package, installs in MS Windows as a printer. All you need to do is choose Adobe Distiller as your printer, launch the print command from MS Word, and your entire MS Word document will be converted to PDF. Since Adobe Distiller emulates a PostScript printer, your EPS graphics will be rendered beautifully.

Convert to PDF in Mac OSX

In Mac OSX, Adobe PostScript emulator comes built-in. You will simply launch the print dialog box, and choose Convert to PDF.

Rasterize your EPS images

If you have neither Adobe Distiller, nor a PostScript compatible printer, you will have to rasterize your EPS images first. This is not a difficult process, you simply need some software to help you with that. GhostScript is a free program that gives you excellent functionality for EPS and PDF files. In itself, it is not of much use, as it requires a Graphic User Interface. There is an excellent image conversion program called ReaConverter Pro, which will "talk to" GhostScript and use it to rasterize EPS images. So all you need to do is

• install GhostScript
• install ReaConverter Pro
• convert your EPS images to any of the available bitmap formats:
• BMP (works best for print output) or
• GIF (works best for web images, PowerPoint imag-es, and other screen resolution purposes).

ReaConverter Pro gives you an option to choose the rasterization resolution. Choose

• 72 dpi for web output
• 300 dpi for print output

See the image below:

The image below has been rasterized from an Akustyk-generated EPS image with ReaConverter Pro as a 72 dpi GIF image: