Figure Guidelines ● Figure Specifications ● Figure Instructions ● Table Specifications ● FAQ
PLOS Figure Instructions
The following are instructions for making figures so that they comply with PLOS Specifications. Often, original figures are not generated in a standalone
graphics application. If your original figures are not either TIFF or EPS, high-quality images can often be made by saving them as PDF, then transforming the
PDFs into TIFF or EPS.
Note about error messages: It is not unusual to encounter QC system error messages when submitting your figure files. Three of these messages can be disregarded:
“AQC error,” “Testing in Progress,” and “Alpha channel.”
2. Software Notes
Many options exist to create and revise figures. In addition to commercial applications such as Adobe Photoshop and Adobe Illustrator, some programs are available without cost.
Microsoft Office products are not ideal for creating or editing graphics files. If this is unavoidable, however, read the notes below, then follow the instructions for
converting figures to TIFF or EPS.
- PowerPoint. To create a high-quality TIFF from a PowerPoint file, use the instructions below. Do not save directly as TIFF, as this will result in a low-resolution image. Important: To add
artwork to your PowerPoint slides, use Insert > Picture > From File. Do not add by copying from another application and pasting into PowerPoint, as the result will be a very low-resolution image.
- Word should not be used to adjust image size. Word automatically down-samples figures and embeds them in the document at very low resolution.
- Excel may be used to generate charts, graphs, or histograms from cell data, or to make tables. It should not be used to create or adjust figures, as it does not handle figures of dedicated graphics applications.
- Paint cannot create high-resolution TIFFs.
Numerous programs can create figures but are not dedicated to working with graphics. These may be limited in their capability to create TIFFs or EPSs that comply with PLOS specifications. Such applications include ChemDraw, Haploview, PyMol,
R, ImageMagick, Corel Draw, GeneSpring, Matlab, Origin, Prism, Sigmaplot, and Stata. To create a high-quality TIFF from images created in other applications, use the instructions below to convert to PDF and then to TIFF or EPS.
Combining Figure Panels
Presentation software such as OpenOffice Impress or MS PowerPoint is recommended for creating multi-panel figures from individual files.
- In setting up the page, use the values listed in Dimensions.
- Use an Insert tool to place figures. Do not drag/drop or copy/paste images into the file, as this results in a 72 ppi image, and PLOS requires 300-600 ppi.
- The quality of a low-resolution figure cannot be improved by increasing the resolution in graphics software. If you create a 72 ppi line graph and place in it a 300 ppi TIFF, the graph will still look blurred, jagged,
or pixelated when enlarged.
- If your figures have numerous pictures, charts, or small text, they will render best at a resolution of 600 ppi.
- Once your Impress or PowerPoint file is complete, follow the instructions below, Converting Figures to TIFF or EPS.
3. Converting Figures to TIFF or EPS
Some applications easily save graphics files as TIFF or EPS, but some do not. If your figure is currently not formatted as either TIFF or EPS, and you don't know how to export directly to one of these two formats, try saving it as a PDF and creating a
high-quality TIFF or EPS from that. EPS files that are larger than 10 MB can be converted to PDF and then a compressed TIFF.
Do not save-as TIFF or EPS directly, as the resulting file will be down-sampled and its resolution far below requirements.
Step 1: Save Figure as PDF
- PDFs can be created in a number of ways. One simple way is to use a PDF generator as the “printer.” From your figure file, select the Print command, then the PDF creation tool instead of a printer.
- Click on Printer Properties. A window containing tabs will open.
- Select the Layout or Paper/Quality tab and click on Advanced...
- Under the Graphic menu item, change Print Quality to 300 ppi and click OK to save the setting.
- Click Print and save the resulting PDF.
- Go to Step 2, TIFF or Step 2, EPS below.
Step 2 (TIFF): Make PDF into TIFF
- Either open the PDF directly in your graphics software or right-click on the PDF's filename, select “Open with...”, and select the name of your graphics software.
- Then, using the tools in a standalone graphics software (Adobe Photoshop, Gimp, etc.):
- Set resolution to 300-600 ppi.
- Set bit depth to 8 bit.
- Crop unnecessary white space, leaving a fine (2 point) border.
- Size the image with proportions constrained, using recommended Dimensions.
- Remove alpha channels using the channels or transparency tools.
- Flatten the image.
- Save the file, using LZW compression.
- In GIMP, do not save-as; use Export and select TIFF as the format.
- In Photoshop, select LZW compression and Discard Layers, and Save a Copy.
Step 2 (EPS): Make PDF into EPS
Important: Because fonts are embedded in PDFs, font substitution may be a problem (this will be obvious when the PDF is opened in the vector graphics software). Therefore, it is recommended that both conversion steps be done
on the same computer. If persistent font problems occur, consider converting the PDF to TIFF instead.
- Either open the PDF directly in your graphics software or right-click on the PDF's filename, select “Open with...”, and select the name of your graphics software. If EPS file is over 10 MB, convert to flattened TIFF with LZW compression.
- Convert text to outlines. To avoid font problems, convert the text in EPS to outlines. When you convert text to outlines, the text is converted to lines and fills, which makes the layout process faster and more accurate. Caution: You will not be able to
edit text after it has been converted to outlines, so make sure it is correct before converting.
- In Inkscape, press Shift + Ctrl + C. In Adobe Illustrator, select Create Outlines from the Type menu.
- Clean up the image by deleting any random boxes or blue dots outside the document bounds.
- Alternatively, you may use our instructions for converting figures to TIFF. To determine correct figure sizing, refer to Dimensions. Click on the Chain/Lock symbol so that it is in the “closed” position. Type in the W (width) and H (height) dimensions below the maximum allowable height.