Charts created in Microsoft Excel can easily be converted into encapsulated PostScript graphics (EPS) once you have installed a PostScript printer driver. Whilst these instructions present examples from Excel 97, they are applicable to Excel 2000 and also to earlier versions. These instructions can be followed by Mac users who have set up a PostScript printer. We've chosen Excel as an example as it is one of the commonest spreadsheet applications but the instructions easily be applied to any other spreadsheet software.
Input your data into a worksheet as you would normally. The easiest way to create a chart/graph is to select the data you want to use and then click the chart wizard icon on the toolbar (1).
It is important that you take care to create your chart according to the standards of the journal (2). Remember that all aspects of the chart remain editable after you have used the chart wizard to create a graph. Please use standard fonts and proportionally size your graph. It is not possible to accurately size a chart in Excel, however we can resize the vector EPS file without affecting the quality of your artwork, provided the graph is in proportion.
Once you are happy with the chart, select the chart by clicking the outer area (the ' chart area ') (3). 'Handles' will appear on the edges of the selected chart. Choose Print from the File menu (4) to call up the Print dialogue box (4). From the drop down list of printer names choose your PostScript printer (eg Acrobat Distiller 3) and check the Selected Chart box (5). If this option is not selectable, cancel the Print dialogue and reselect the chart and go back to (4).
Finally, when prompted, choose a place to store the file and a filename (our filenaming convention). Please note that Excel 97 does not allow you to choose a suffix other than .prn. You can rename the file once you have created it with an .eps suffix.
Figures created in all versions of Microsoft PowerPoint can easily be converted into encapsulated PostScript (EPS) graphics once you have installed a PostScript printer driver. Whilst these instructions present examples from PowerPoint 97, they are applicable to PowerPoint 2000 and also to earlier versions. These instructions can be followed by Mac users who have set up a PostScript printer. We've chosen PowerPoint as an example as it is one of the commonest presentation applications but the instructions can easily be applied to any other presentation software.
When starting a new presentation, open PowerPoint and select New Presentation in the opening dialogue box, or Open Presentation if you wish to modify a previous figure. When choosing an Autolayout, you'll probably want to choose a blank slide. The default setup in PowerPoint is for on-screen viewing and it may be difficult to relate to how the figure will appear in print on paper. You may find it easier to change the default on-screen presentation to A4 by clicking File->Page Setup and selecting the correct option (1).
Once you have the desired layout (in this case A4 portrait), figures can be created as usual but with a view of the figure as it will appear on a page rather than on screen. This example shows how to import a bitmap image whilst retaining its size and resolution. Photographic (continous tone) images are problematic as the print result is dependent on size and resolution while text and line art (e.g. a cut and pasted chart from Excel) can be resized without impact on the final print quality. A continuous tone image should be 250–300 dots per inch (dpi) at its final size for print reproduction – enlargement will reduce the resolution and should be avoided.
The histological micrograph in this example is 8.1 cm wide at 250 dpi. An image is imported by selecting Insert->Picture which produces a dialogue box for selecting the image file. The imported image then appears superimposed on the page but at a larger size than the original file. This is because PowerPoint imports images at an on-screen resolution, i.e. each dot in the image is reproduced as a pixel on screen. The resulting resolution is 72–96 dpi and too low for quality print. The resolution can be restored by resizing the image to its original size (2).
Images can be resized in PowerPoint by selecting the Format menu and choosing picture. This will open the Format Picture dialogue box (3). Click the Size tab and ensure Lock Aspect is checked so the aspect ratio of the picture is unchanged. The original width can then be entered in the Width box (in this example, 8.1 cm). Clicking OK will resize the picture and in the process return the resolution to its original value. The image can now be annotated or other images added.
In the example a composite figure has been created from the micrograph and a graph cut and pasted from Microsoft Excel. Using PowerPoint, part of the micrograph has been annotated with an arrow and the letters ‘a' and ‘b' have been added to identify each panel in the legend. When annotating a figure try to avoid too much detail as this can be distracting. To avoid problems with missing fonts and characters try to use standard fonts. Sans serif fonts also help distinguish the lettering on your artwork from surrounding text. When sizing the figure, check that the widths correspond with column widths in the journal or sizes recommended in the instructions to authors and try to use a sympathetic font size for labelling and annotating. When placing several panels, ensure the gaps between each are constant and are no wider than 4mm.
With the final figure on screen, select File->Print to call up the Print dialogue box. From the Print dialogue select your PostScript printer from the pull-down list of printers (e.g. Acrobat Distiller 3.0). If you already have a PostScript printer physically installed, you can use this with Print to File checked. In all cases ensure Current slide is checked. If your image consists of only black and white check the Pure black & white option, otherwise (as in the example) check Black & white for monochrome images. For colour images, neither of the boxes should be checked. Click OK. Please note that PowerPoint treats white as a colour, so if you have used white text do not check either of the boxes.
The Print to File dialogue box will now appear. Choose the location where the file is to be saved, and select Save as type All Files and enter a logical filename, for example
which will allow us to identify the file easily. The .eps suffix makes it clear that the file is encapsulated PostScript. Clicking OK will create the file on disk.