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How to use additional files

How to use additional files | Guidelines for specific types of additional files

This page provides general information for authors creating additional files to maximize the quality of those files. Guidelines on supported file formats and types of files are also available.

Introduction

Additional files are files containing additional information that supports or expands upon items referred to in the main manuscript.

Additional files will be linked to the final published article in exactly the same form you supplied them in, but will not be displayed within the article in this format.

You are encouraged to provide large data sets, tables or figures, movie files, software or other information as additional information. Results that would otherwise be indicated as "data not shown" can and should be included as additional files. Additional files are considered integral to articles published by BioMed Central. There is no distinction between the main article and 'supplementary material'. See the Additional Files Quick Reference for more information.

Figure files and tables should only be uploaded as additional files if they are too large. See tables (small, portrait, csv or excel) and figures (larger than one page).

Since weblinks and URLs frequently become broken, we require that all supplementary data are included as additional files rather than links to web pages. You should upload these files using the 'Additional material files' button in the manuscript submission tool.

Inserting and referencing

If additional files are provided, please list the following information in a separate section after the reference list:

  • File name (e.g. Additional file 1).
  • File format including the three-letter file extension (including name and a URL of an appropriate viewer if format is unusual).
  • Title of data.
  • Description of data.

Additional files should be named "Additional file 1" and so on and should be referenced explicitly by file name within the body of the article.

Additional files should be numbered in the order they are first mentioned in the text, and uploaded in this order.

File size and resolution

The maximum file size for additional files is 20 MB each and files will be virus-scanned on submission.

Data over 20 MB should be deposited in a suitable permanent repository for that type of data, where one exists (e.g. GEO for microarray data). Where a specific repository for that particular type of data does not exist, use Datasets.

Additional files can be submitted in any format.

Instructions for commonly submitted file types are available within guidelines for specific types of additional files.

Frequently asked questions

  1. What are Additional files?
  2. What is the difference between an additional file and a figure file?
  3. Can I upload my figures files as additional files?
  4. Why is it important to include additional files?
  5. How large can additional files be?
  6. Is there a limit to how many additional files I can include?
  7. Can I use image manipulation software to increase the clarity of images within additional files?
  8. Within my manuscript, can I make references to individual items within my additional files?
  9. Can I submit earlier versions of the final manuscript as additional files?/li>
  10. Can I cite references in additional files?
  1. What are Additional files?
    A. Additional files are files containing additional information that supports or expands upon items referred to in the main manuscript. All additional files must be referenced in the main manuscript.
  2. What is the difference between an additional file and a figure file?
    A. A figure file is an image file that will appear in the final published manuscript. On the other hand, additional files will be made available alongside the published manuscript, but will not be visible within it. Additional files should be named "Additional file 1" and so on and should be referenced explicitly by file name within the body of the article.
  3. Can I upload my figures files as additional files?
    A. The only time you should do this is when the figure image must be larger than A4 in order to be legible.
  4. Why is it important to include additional files?
    A. Additional information is considered integral to articles published by BioMed Central. You are encouraged to provide data sets, tables, movie files, software or other information as additional information. Results that would otherwise be indicated as "data not shown" can and should be included as additional files.
  5. How large can additional files be?
    A. You should aim for all additional files to be as low a file size as possible. The maximum file size for additional files is 20 MB each.
  6. Is there a limit to how many additional files I can include?
    A. No; you can include as many relevant additional files as necessary.
  7. Can I use image manipulation software to increase the clarity of images within additional files?
    A. Enhancement of digital images using image-editing software is acceptable practice if carried out responsibly. However, it is crucial that artefacts are not introduced and the original data is not misrepresented.
  8. Within my manuscript, can I make references to individual items within my additional files?
    A. Yes, items within additional files can be referenced in the main manuscript. However, please use the format set out in the following example: “See Supplementary Table 1, Additional File 1”.
  9. Can I submit earlier versions of the final manuscript as additional files?
    A. No.
  10. Can I cite references in additional files?
    A. You can cite references in additional files, as long as you list them in a separate section within the additional file; any references that are only cited in the additional files should not be listed in the main manuscript reference list.
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