GraphPad Prism 8 User Guide

The differences between export formats

The differences between export formats

Previous topic Next topic No expanding text in this topic  

The differences between export formats

Previous topic Next topic JavaScript is required for expanding text JavaScript is required for the print function Emails questions or corrections.  

Setting the default export format and the default for copying to clipboard

Set the default for how Prism copies graphs and layouts to the clipboard in the File & Printer tab of the Preferences dialog. Choose the export format in the Export dialog, and check an option at the bottom of that dialog to set the default for future exports.

PDF

Prism's PDF files encode vectors and fonts (not bitmaps), so the resulting file can be stretched to any size with no loss of quality. Export in PDF format when you can.  Unfortunately, few Windows programs import pdf images, and few journals accept them. In contrast, PDF is the preferred format for transferring images between Mac programs.

Notes:

If your graphs are in color, you will need to choose between RBG and CMYK color model..

You don't have to have Adobe Acrobat to export PDF files. Prism creates PDF files on its own.

When exporting several graphs or layouts, you can choose to export all of them to one PDF file. Or you can  ask Prism to create a separate PDF file for each sheet.

Prism Mac and Windows can encode transparent colors in PDF export.  

 

TIFF or TIF

(Prism uses the extension TIF but it is identical to TIFF used by some other programs. The two are exactly the same, and you can rename from one to the other.)

This is a bitmap format, which means that your graph or layout is turned into a collection of dots.  TIFF files tend to be trouble-free when submitted to journals. You need to choose resolution, color model, and size.

The resolution is expressed as dots per inch (dpi). Computer screens display images at about 100 dpi. Computer printers generally print at 300-600 dpi, and publications are generally printed at 1200 dpi. Journals typically ask for a file at 1200 dots per inch (dpi), the highest resolution that Prism offers.

Choose between two ways to express colors: RGB (designed for computer monitors or projectors) or CMYK (designed for printing). If you are submitting to a journal, follow their instructions. If in doubt, choose RGB. Prism Windows also lets you choose Monochrome files, which are pure black and white with no grays. If you choose RGB, Prism Windows lets you choose between 256 colors (smaller files) or millions of colors (larger file, but more accurate color rendition). Prism Mac always uses millions of colors.

Typically, graphs and layouts in Prism projects are much larger than publication size. If you ask for a graph at 1200 dpi at the actual size in Prism, you will end up with either a huge file or an out-of-memory error message. Avoid this problem by specifying the publication size. Let’s say your graph is 6 inches wide, but you will publish it with a width of 2 inches. By checking the option to reduce the graph to a width of 2 inches, you will create a file one-ninth as large (one-third the width times one-third the height).

With TIF format, and no other, Prism lets you choose to compress the file. The advantage of compressing, of course, is that the file is smaller. The disadvantage is that compressed TIF files might be less compatible with other programs.

With Prism Windows, choose between two compression methods. PackBits compression create the smallest file size, but  LZW (Lempel-Ziv-Welch) compression might be more compatible.

Prism Mac does not offer you a choice of compression methods, it uses LZW compression

TIFF files exported by Prism (Windows or Mac) encode transparent colors.

 

EMF+, EMF or WMF (Windows only)

Windows Metafile (.WMF) and Enhanced metafile (.EMF) 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 (and Prism Mac cannot export in these formats).

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:

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.  

If you paste an EMF image into PowerPoint, the colors may change when you save then reopen the file. Not with WMF or EMF+.

Choose EMF  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.  

Choose EMF instead of "EMF+" to when a graph is sent to PowerPoint and then exported to PDF. WIth EMF+, the fonts can change.

Some very old programs do not support EMF. For these choose WMF.

EMF and EMF+ files exported by Prism encode the transparent (clear) "color", but WMF files cannot encode transparency.

EMF+ but neither EMF(old) or WMF can encode semitransparent (semi-clear) colors.

EMF+ is a newer format than EMF but both kinds of files use the same .EMF extension.

 

EPS

Like PDF, EPS files contain vectors and fonts. The resulting file isn't just an EPS wrapper around a bitmap file. Prism Windows gives you the choice of converting text to outlines. If you do that, the image will always look right (no font files required), but you wont be able to edit text in other programs. If you include text as text, it can be edited elsewhere but font files are required. Prism Mac always converts text to outlines.

In theory, the EPS format is the best (tied with PDF). It encodes everything as vectors and fonts, so can be expanded or shrunk without any loss of resolution. In fact, submitting EPS files to journals is often problematic. Fonts and EPS files.

The EPS format is unable to encode transparency. If you choose any transparent colors in Prism, they will look solid in the exported file.

JPEG

The .JPG format is designed for photographs with gradients of similar colors. It is not a particularly good format for exporting for line art and graphs. Prism offers this choice because some journals insist on it, but we recommend that you use the .TIF format when possible. The only advantage of .JPG is that the files are smaller.

Most programs that export to the .JPG format give you a choice of compression. If you compress more, the files will be smaller but the resulting image won’t be as sharp. Prism gives you no choice. It only exports to the .JPG format with the least possible compression, making larger files but sharper images. Any compression would reduce the clarity of your graphs noticeably.

The JPEG format is unable to encode transparency. If you choose any transparent colors in Prism, they will look solid in the exported file

PNG

The .PNG format is great for posting graphs on web sites. PNG files use screen resolution, which is fine for displaying on screen but is too little resolution for submission to printed journals. There are no options of color depth.

Prism Windows can encode transparent colors in PNG export. Prism Mac cannot, and any transparent colors in your graphs become solid in the exported PNG file.

BMP

This is an older format that offers no advantages over other formats.