Tables and figures (illustrations)

Tables and figures should be referred to in the text at the place at which the author wishes them to be incorporated. In the final copy, they will be placed as close as possible after the first mention in the text. Titles should be a single, concise sentence. Extensive footnotes should be avoided. Information provided should illustrate, not duplicate, that given in the text (a table or figure can conveniently and effectively replace a complicated list or paragraph in the text). Tables are assigned Roman numerals and figures Arabic numerals. Each table and figure should be presented on a separate page at the end of the text, after the Reference section. Tables and figures will either be presented in a single column (7 cm or 2 ¾") or over the full width of the page (15.4 cm or 6"). Please use the Century Gothic font for titles, texts, x- and y-axes and legends.

Tables

• Each table should be numbered consecutively (I, II, III) according to the order of citation in the text.
• Tables with only one or two rows or columns should be presented in the text.
• All columns should have a heading. Additional or new column headings should not be added within the table; rather create another table.
• Three horizontal lines are used: one above and below the header and another to close the table. No vertical lines are used (see model Table).
• Numbers within tables should be rounded to the nearest whole number or significant digit. Numbers smaller than 1 should include a zero to the left of the decimal point.
• Footnotes that provide essential comments and explanations should be assigned superscript letters, i.e. (a), (b), (c) within the table. Explanations to the footnotes appear below the table and should be brief, providing descriptive statements that pertain to the data or specific formatting in the table only. Abbreviations should be explained.
• Tables should be as simple as possible and be composed entirely of text characters. Large or complex tables or tables that include graphics should be submitted as figures. If in doubt, please contact the journal for advice.
  

Figures

• Photographs, diagrams, graphs, maps and drawings are considered as figures.
• If a figure has been published previously, the original source should be acknowledged after written permission from the copyright holder to reproduce the material has been received.
• Each figure should be formatted so that it occupies no more space than is necessary to convey critical information; no margins or borders should appear around figures. Legends should be concise and informative, detailed descriptions are often more appropriate in the text of the manuscript.
• The following software can be used: Photoshop®, JPG, Microsoft® PowerPoint®, CorelDRAW™ and Excel® (data used to create the graph must be included in the file in which the figure is presented).
• Please ensure:
  • figures are labelled with their number outside the actual figure itself
  • lettering size does not vary too much within the figure and between figures
  • scale bar or magnification information is included for all micrographs.
    

Graphs and histograms

• Graphs should be created using Microsoft Excel®, or a similar program. The editor should be able to make changes to the colour, text, background fill, etc.
  Consult model graph/histogram.
• The following tips may be of assistance:
  • size the graph/histogram to a single or double-column format of the printed page
  • no horizontal lines or border should be given, no background colour fills should be used
  • the titles of the x- and y-axes should be in Century Gothic font size 9, with only the first word capitalised. Data series should be in size 8. Legends should be presented in size 9 below the figure (without a border)
  • acronyms should be written in full.
    

Digital graphics files

The following may be of assistance when creating digital images to ensure high-quality printing. Vector graphics are different from raster graphics in that a vector graphic is a mathematical definition of an image. It is independent of size or colour. It remains crisp and clear and is independent of pixels which can become deformed on enlargement (raster).

Vector graphics are composed of lines and curves. Mathematical relationships define the pathways among the lines and curves within the figure. Vector graphics can be enlarged to any size and printed at any resolution without losing quality and consequently are always excellent for high-quality printing.

Raster graphics (or bitmap images) are composed of pixels that form a grid. Each pixel is assigned a specific colour and shade, which allows for variations of tone. When a raster graphic is significantly enlarged, the pixilated grid begins to show, which will give a jagged edge to any line or element that is not entirely vertical or horizontal. Raster graphics have a resolution which indicates how many pixels or dots per inch (ppi or dpi) were used to create the grid. The higher the number of pixels or dots the better the quality of the figure will be. Raster graphics are suitable for high-quality printing only when a sufficiently high resolution is used. Minimum resolutions required are given below:

• line art (composed solely of black and white, without any greyscale tone: 1 200 dpi)
• halftones and colour images (with no text outside the toned area: 300 dpi)
• combination art (halftones or colour images with text outside the image area: 600 dpi).

Programs that can create vector graphics include Illustrator®, FreeHand®, Corel Draw™, Photoshop®, PowerPoint®, Excel®, several charting and graphing programs and some word-processing programs such as Word. If the figure was created in one of these, it should reproduce well in print. Saving the figure in its native format or exporting it as an EPS file will retain the vector qualities of the figure. Vector qualities will be lost when saving or exporting the figure as a TIF or JPG file. Panels that include tone variations, such as gels or photos, must be raster (composed of pixels) in order to show the tone variations. All scanned figures are raster. Any file saved in Photoshop® or saved as a TIF or JPG is raster unless the file is specifically saved with vector data preserved, which will usually create an exceptionally large file.

Raster elements within vector files: if a raster element is pasted or imported into a vector program, the raster element must have a minimum resolution of 300 dpi when sized at final print size before pasting or importing into the vector program. This figure file will contain both raster and vector elements. The file must be saved in its native vector program format or as an EPS to retain vector qualities.

File types

It is always advisable to provide the native format of the image. EPS, TIF, JPG and PowerPoint® files can be used. When saving files as TIF, always use LZW (Lempel-Ziv-Welch) compression to reduce file size and to ensure no data is lost.

Final print size

The maximum print area on a journal page is 15.4 cm widex23 cm long (6" x 9"). Figures will be printed either as a:

• single column: 7 cm (2 ¾") or
• double column: 15.4 cm (6").

Figures will be reduced where possible.

Figure preparation and layout

Consider the impact that font and/or label size and position will have when reduced. Present graphs in a similar fashion to ensure consistency throughout the manuscript.
Particular attention should be paid to the quality of lines, symbols and patterns; fine lines may disappear and heavy lines may be blurred if and when reduced. Avoid shading and dot patterns on bars, as these will not reproduce well. Use open and solid bars with colours. A key should be used to explain colour codes on graphs. Do not use 3-dimensional graphs to show 2-dimensional data.
Multiple parts within a figure must be assembled in a single file as they will appear in print with identifying letters (Fig. 3a, 3b, 3c).
If different graphs will be repetitive or relational, it may be advantageous to combine them into a ‘plate’. All figures would appear together but be labelled individually and referenced separately in the figure legends.
Do not place unnecessary graphics, such as a border, in or around the figure.

Fonts
Please use Garamond, Century Gothic or Symbol, as they are among the more common fonts and can be reproduced consistently. As Asian fonts, in particular, do not convert well; please ensure your text (including spaces), figures and symbols do not use these fonts.

Symbols
If special symbols are used from a very different font, please ensure that these are highlighted when the manuscript is submitted.

Type size
Avoid unnecessarily large or small type sizes (not below 8 points). If the figure is reduced in size, check whether the labels are too small to read or are larger than necessary.
Type should be the same size (or proportional) on all figures within an article; elements of type within a figure should be proportional to each other. If the figure is likely to be reduced, check that all labels can be read at a smaller size.

Labelling
The x- and y-axes should be labelled clearly with measurement units. Molecular standards should not be identified with a kDa label; use Mr x 10–3 (molecular weight [relative molecular mass]) or kb (kilobase) as appropriate.
Check figures carefully to ensure that necessary and accurate information is included in the lettering and labelling. Use decimal points instead of commas and italicise species or genes.

Legends
Methods or results should not be discussed in figure legends. Print legends below the figure in double-spacing.
Use numbers and letters consistent in style (i.e. upper or lower case letters) with those used in the illustration. Do not use special symbols in the legend. Special symbols in the figure should be shown in a key that accompanies the figure and described in the legend. All abbreviations that appear on the figure should be described. The scale used for micrographs (e.g. bar = 1 µm or Original magnification x200) should be indicated and is best placed at the foot of the scale bar.