How to prepare figures for submission
Two common problems for authors’ submitted figures are low resolution and an image size too small. Our journals required that all figures to be shown in main text meet the following resolution and size requirements:
- Halftones (color or grayscale): 300 dpi (dots per inch) or ppi (pixels per inch)
- Halftones with text: 600 – 900 dpi
- Line art (black and white, no shading): 1200 dpi
For B&W line art, B&W halftones/combo halftones, and color halftones set TIFF model as bitmap, grayscale and CMYK respectively.
- Figures should be sized at 100% publication size with a width between 3.0” and 7.5”, a height not exceed 9.8”. When viewed at print size, all text and labeling should be legible.
- How to know the size of an image: 1) Open the image in Photoshop à Image à Image size; or 2) open the image in any application (e.g., Windows Explorer), check its properties and write down its resolution and dimensions. Its print size in inch should be width (pixels)/resolution (ppi) x height (pixels)/resolution (ppi). For example, an image of 300 ppi and 1800 x 1200 pixels has a print size of 6” x 4”.
How to meet the resolution requirements: If you have an existing low resolution image, you cannot fix the low resolution issue by simply increasing the resolution values in an image editing software (e.g., Photoshop) since adjusting the resolution field in the existing file does not create more dots per inch, but only decreasing image dimensions.An appropriate way of creating a high resolution image is to first create a new image file with its resolution set at the required value shown above, and its size (dimensions) not exceeding the size of a print page (7.5” x 9.8”, which is equivalent to 2250 x 2940 pixels for a 300 pixels/inch image).
General guidelines for creating images of acceptable quality (using Photoshop as an example):
- If image components are to be obtained from a scanner, scan originals at high resolution and then import them into Photoshop.
- If image components are to be exported from other applications, export them as EPS or TIFF format.
- Create a new file in Photoshop, and set its resolution according to the resolution guidelines shown above, its width between 3.0” and 7.5” and height no more than 9.8”.
- Import image components from other applications such as MS Powerpoint, MS Word, MS Excel by coping and pasting in Photoshop, or open exported images from other applications in Photoshop, and then copy and paste the images into the new file.
- For line art and drawings made in MS Powerpoint, MS Word, MS Excel, WordPerfect, or other non-graphic applications, you can also save them as PDF files, and then open the PDF files in Photoshop.
- Combine multi-component figures into one file and use bold Arial or Helvetica font to label each component as A, B, C, etc.
- Crop all images closely with no excess white space.
- All figures followed by their legend should be embedded in main manuscript in the place where they should appear in the text or at the end of the main text (after references).
- Upload individual image files in TIFF format as supplementary files to the online manuscript submission system.
- All supplementary figures with their legend showing below should be embedded in a single MS Word file. Authors can submit the MS Word file or the converted PDF file.