Preparing figures for publication
In order to ensure the quality of published figures, authors should follow the guidelines below when preparing their figures. Providing figures that do not meet the required quality standards can result in a delayed publication.
1. File format
Recommended file formats are:
- EPS – if figures are being created from scratch or compiled from high-resolution component parts in software such as Adobe Illustrator or Corel Draw, we recommend exporting to EPS.
- TIFF – see section 2 for resolution requirements; TIFFs are preferred to JPEGs.
- PDF – if figures are created from scratch or compiled from high-resolution component parts in, for example, PowerPoint; see section below on PowerPoint.
1.1 Use of PowerPoint and WordWhile PowerPoint provides a convenient way of creating figures from scratch, compiling multi-part figures and labelling figures, it is not inherently designed to generate production-quality artwork. As such, the following guidelines should be borne in mind if using PowerPoint:
a) When inserting images into PowerPoint to assemble figures they should be (i) of sufficient resolution (see Section 2) and (ii) added to the PowerPoint file using the insert functionality, not by copying and pasting.
b) Label the figure in PowerPoint.
c) Do not export to graphic file formats such as TIFF, JPEG, PNG or GIF from PowerPoint; its default export settings for these file formats result in resolutions that are too low for production.
d) Export to PDF; this will retain the quality, particularly the sharpness of lettering added via PowerPoint.
1.2 Figures provided as PDF
PDF is a universal file format that preserves all the fonts, formatting, graphics and colour of a source document, regardless of the software used to create it. As such, we can accept figures supplied as PDF; however, the images in source formats must themselves be of sufficient quality and resolution (see section 2).
2. Resolution and image quality
Lettering, including labels, should be sharp and defined, not blurred, grainy or overly pixelated. We strongly recommend that figures are reviewed carefully before submission.
For so-called ‘raster’ image formats (e.g. TIFF, JPEG, PNG), the resolution value of the image is related to its quality and authors are encouraged to provide these at as high a resolution as possible.
Colour/grayscale photographs with text or line art elements – e.g. labelled gels/micrographs: 600 dpi
2.1 Compiled image resolution
When a figure is composed of multiple images, each individual component should be prepared at high resolution; use of low-resolution images is discouraged.
For example, if a multi-panel 600 dpi figure is being prepared in Adobe Photoshop, a 600-dpi component part will retain its size if added to the file. However, if a low-resolution (72 dpi) component part is added, its size will be in inverse proportion to the increase in resolution to make it 600 dpi.
3. Figure size
Ideally, figures should be prepared at the size at which they will be published.
Authors should be aware that figures may need to be resized during the production process. The standard dimensions of the text area on a page in our journals are: width, 16 cm; height 22 cm.
Authors should consider these sizing parameters when preparing figures, especially with regard to the lettering and labelling. For example, what is legible on a figure prepared at a width of 25 cm, may become too small to read when the figure is reduced to a width of 16 cm.
Figures should be cropped to minimize the amount of surrounding white space.
3.1 Figures with multiple panels
Figures with multiple panels should be compiled in such a way that when they fit on the page of a published article, text is sufficiently large to read and key details can be visualized. For example, this figure:
Might be better presented as:
4. Other factors to consider
a) Scale of microscopic image: microscopic images should feature a scale bar; the length of the scale bar stated in the figure legend, preferably, or in the image. Magnification factors (e.g. x40) should not be used to indicate scale.b) Molecular weights and fragment sizes: protein molecular weights or DNA marker sizes must be indicated in all figure panels showing gel electrophoresis.c) Combination of colour/text backgrounds: contrast between text and background colours affects some people’s ability to perceive information, for example: