Preparation of figures for Publication in Clinical and Experimental Pharmacology and Physiology

Transcription

1 CEPP Guidelines for Preparation and Submission of Figures 1 Preparation of figures for Publication in Clinical and Experimental Pharmacology and Physiology Important Note: Submitted manuscripts with figures that are not of publication quality, or that do not accord with the requirements of these guidelines, will not be sent for peer review. Authors will be asked to improve the figures before resubmitting their manuscript. Because CEPP is an online-only journal, colour figures are published at no cost to authors. We encourage the use of colour in figures. However, whenever possible authors should produce their colour figures in a way that allows the figures to be understood even in black and white. Preparation of Figures 1. Figures will be greatly reduced in size for publication. There are two standard figure sizes (84 mm and 176 mm left to right). That is, figures are placed either within a single column of text with the legend underneath (84 mm) or across the entire page with the legend underneath (176 mm). Where possible, figures will be reduced to 84 mm across, so that they fit within a single column of text. In practice, this means that multi-panel figures should be arranged to fit portrait on a page rather than landscape. 2. Remove any unnecessary information from figures. Redundant material in a figure distracts the reader and so hinders transmission of the message you want them to get from the figure. 3. All lines, whether for plots, axes or line diagrammes, should be of a consistent thickness. Furthermore, a relatively large font size should be used for all labels. A sans-serif font such as Arial should be used rather than a serif font like Times New Roman. The text should not be in bold or it will be too thick when reduced. After reduction, the size of the font should be approximately 8 point. In other words, capital letters should be approximately 2 mm tall after reduction. Authors, therefore, must scale font sizes according to the expected degree of reduction. That is, if the original figure is 17 mm wide the lettering should be 16 point (4 mm high capital letters) in order for it to be reduced to 84 mm wide. Authors are encouraged to prepare multi-panel figures to represent related data. Such figures should be submitted fully formatted as a single image accompanied by a single legend. Each panel of a multi-panel figure should be labelled with lower case roman letters at the top left hand side of each panel (e.g. (a), (b) etc). Multi-panel figures should have as little wasted white space as possible. 4. Figures should not be enclosed within a box and any redundant axes (right or top) should be removed. 5. When graphs include several curves, different symbols should be used to denote the different lines, but the lines should remain solid unless it is absolutely necessary

2 CEPP Guidelines for Preparation and Submission of Figures 2 to use dotted or dashed lines. Symbols should be sized so that they are approximately 1.5 mm tall in the published paper. 6. Symbols should be used in the following order: Colour symbols may be used if more than six plots are required. 7. The use of colour in figures is encouraged. However, whenever possible authors should ensure that their figures can also be interpreted in black and white. 8. When multi-panel figures have common axes that are aligned, the figure labels should not be repeated in each panel. Rather, the labels should be shown at the bottom of the page (for x-axes) and at the left of the page (for y-axes) only. The y- axis title should run vertically, parallel to the axis. 9. Use the least number of significant figures possible for the numbers that define the scale of axes. 1. Ticks should be directed inwards unless there is a specific requirement for out-ward directed ticks. Use the minimum number of ticks necessary to allow the reader to interpret the figures. Grid-lines within a figure are discouraged, unless absolutely necessary. 11. Histograms should be two dimensional, unless it is absolutely necessary to introduce a third dimension (e.g. an XYZ plot). Simple open and closed bars should be used if only two samples are being compared, with open bars representing the nominal control sample. Use of subtle shading for bar fills is strongly discouraged, since it is difficult for readers to discriminate between different shades. In complex histograms the bar fills for various experimental conditions should be used in the following order (left to right):

3 CEPP Guidelines for Preparation and Submission of Figures Standard error or standard deviations may be represented as vertical lines with horizontal cross-bars. 13. Where possible, authors should show original data in their figures. That is, dot plots are preferred to dynamite plunger plots. 1 Comparison of a dot plot with a dynamite plunger plot : Two datasets, with the same mean value, displayed as either dynamite plunger plots (left) or dot plots (right). The bars are mean values: error bars indicate standard error of the mean. Figure and legend modified from 1 with permission.

4 CEPP Guidelines for Preparation and Submission of Figures 4 Requirements for submission of Figures 1. All figures (graphs, line art, photographic images or combinations of these) should be saved in EPS or TIFF format at a resolution of at least 3 dpi for halftones and 6 dpi for line art figures at final size. Some images may need to be saved at a greater resolution to provide optimal clarity. 2. Perform a visual check of the quality of the generated image. You should be able to zoom in to about 3% without the image becoming noticeably blurred or pixilated. If the image does appear pixilated at this zoom, then try going back to the original image and check that it complies with the recommended format and settings. Be aware that copying images across various formats will result in degradation of the image, even if it is saved as a high resolution image (see Example 7, below). 3. All figure files should be labeled Figure 1, Figure 2, etc. and the figure page should also be labeled Figure 1, Figure 2, etc. 4. Once all the files have been uploaded it is very important that authors carefully check the PDF proof, to ensure that the quality of the figures is of the standard set by the journal. If the figures do not look professional, then the manuscript will not be sent for review.

5 CEPP Guidelines for Preparation and Submission of Figures 5 Examples of acceptable versus unacceptable figures Example 1: A simple line graph The example on the left is unacceptable because: 1. The lines are too thin and the font sizes are too small. Thus, it would not be very legible when reduced to 84 mm across. 2. There are unnecessary lines at the top and the right of the figure. 3. The large number of ticks over-complicates the figure 4. The fact that the y-axis does not start at zero may misrepresent the nature of the relationship between x and y. These problems have been rectified in the right hand figure. Example 2: A multi-panel graph: A B C D 12 E 12 F

6 CEPP Guidelines for Preparation and Submission of Figures 6 The figure above is unacceptable because: 1. It is set out in landscape format rather than portrait. Sometimes this cannot be avoided, but whenever possible figures should be set out in portrait format (below) so that they can be placed within a single column of text. 2. While the line thickness and font size is appropriate for a simple figure (example 1), the lines are too thin and the font size too small for a complex figure. Slightly thicker lines and larger fonts are used in the example below. 3. There are unnecessary tick and axis labels that have been removed in the figure below. 4. Panel labelling should be lower case in parentheses, not capitals (a) (b) (c) (d) (e) (f)

7 CEPP Guidelines for Preparation and Submission of Figures 7 Example 3: A simple histogram 2 15 Condition 1 Condition Condition 1 Condition A B C D State A B C D State The example on the left is unacceptable because: The shading used for condition 1 is too subtle and the line thickness for the hatch pattern for condition 2 is too thin. There is no need to place a box around the internal legend of the figure. Example 4: A complex histogram A B C D E F G H A B C D E F G H The figure on the left is unacceptable because: 1. It is difficult to discriminate between the subtle shading for conditions B, C and D. 2. The line thickness for the hatch pattern for condition E is too thin. 3. The patterns for conditions F, G and H are too complex. 4. The overall progression of fills is not logical, so does not help the reader understand the content of the figure in an intuitive way.

8 CEPP Guidelines for Preparation and Submission of Figures 8 Example 5: A micrograph 1 um 1 µm Original micrograph courtesy of Ms Priya Kalaignanasundaram The micrograph (of kidney tissue) on the left is unacceptable because: 1. The resolution of the image is too low. If you zoom in on these images you will be able to see clear microvilli in the image on the right, but not in the image on the left. You will also note that the glomerular capillaries in the left-hand image are rather fuzzy. 2. The line for the scale bar is too thin. 3. Instead of a mu symbol for µm, a u is used. 4. The scale bar is difficult to resolve on the complex background. Example 6: A line diagram Variable A Pathway B Sensor C Variable A Pathway B Sensor C Mediator E Mediator E Phenomenon D Phenomenon D

9 CEPP Guidelines for Preparation and Submission of Figures 9 The line diagram on the left is unacceptable because: 1. A serif font is used (Times New Roman). These can add to readability in printed material but detract from on-screen readability. For this reason, sans serif fonts (e.g. Arial, as used in the image on the right) are preferred for figures. 2. The font size is not consistent. 3. Lines are too thin. Example 7: Figure resolution The example on the left has low resolution so appears fuzzy. This can occur if the original software used to create the figure is not capable of producing high resolution figures, or if it is not set up in the correct way. It can also occur if images are copied multiple times in different formats, particularly if images are saved as bit-maps, which inherently have low resolution. Figure Legends Legends should start with a short and simple title which tells the reader what the figure is about. Details of the figure should then follow, including the nature of the data presented (means or medians?, standard errors or standard deviations?, number of observations?). All abbreviations used in the figure should be defined in the legend. The guiding principle authors should follow is that the figure, along with its associated legend, should be interpretable in the absence of the text. Note, however, that authors should not interpret their data in the legend. Rather, they should provide the reader with the information they require to interpret the figure themselves.

10 CEPP Guidelines for Preparation and Submission of Figures 1 References 1. Drummond GB, Vowler SL. Show the data, don't conceal them. Clin. Exp. Pharmacol. Physiol. 211;38: Acknowledgements We thank Dr Gordon Drummond, University of Edinburgh, for preparing the plunger/dot plot figure shown in this document. We also thank Ms Priya Kalaignanasundaram for preparing the micrographs of kidney tissue in Example 5.