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Navigation: Exporting images from Prism

The size of exported graphs and layouts

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How to change the size of a graph in Prism

When exporting a graph to submit to a journal, you will often want to set the exact width of the graph, and any other objects (text, legends, drawing, pictures, results tables) on the graph page. There are two ways to change the size of the graph in Prism:

Set the width of the exported graph on the Export dialog.

On the graph page. Drop the Change menu and choose Resize Graph.

A third possibility is to change the length of the X and Y axes in the Format Axis dialog. But just sets the axis length. The full graph will be larger when you consider titles, numbering,  legends, drawing etc.).

We recommend the second approach above (change the size of the graph in Prism), as you can then check that nothing is too small. One guideline (from Cadmus, who handles production for many journals) is to make no font be smaller than 6pt, and no line be thinner than 1/2 point.  

What happens when you resize exported images?

EPS, PDF, WMF, EMF files

The EPS, PDF, WMF and EMF formats are all based on vectors and fonts. These formats essentially store the instructions to draw the graph. You can stretch them to any size, and they should still look great. The only exception is if you pasted a picture onto your graph. Then that picture will remain a bit map in your EPS (etc.) file, and may not look great if its size is changed.

Even though it shouldn't matter, it is not a good idea to create an oversize graph, and expect the journal to reduce the graph size (and thus increase its resolution for TIFF files). Journals prefer that you export the graph at the size it will be published.

TIF, PNG, BMP, JPG files

TIF, PNG, BMP and JPG files encode bitmaps. If you stretch or shrink these images in another program, that program has to figure out how to create extra pixels or remove existing ones. Often the image becomes a bit blurry. It is much much better to resize in Prism (in the Graphs section) and then export the bitmap image file at exactly the size you want it to end up at.

If you want to know the size of an image, beware of viewing it after importing  into another program. The size you will see in the other program depends on how that program deals with the mismatch of dots-per-inch (dpi) between the file and on screen, and also on what view zoom setting you have in that program.

It is easy to find out how large an image is in pixels, and its dpi:

Mac. Double-click to open in Preview and then drop the Tools menu and choose Show Inspector.

Windows: Double-click to open in Photo Viewer, then drop the File menu and choose Properties. (This works for Windows 7; other versions are similar.)

 

 

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