Editing scientific images – do’s and don’ts

26 June 2013

​Images represent a very important source of information in scientific articles. Much of what we conclude comes from what we see. Images can be manipulated to help us see better what is in the image by doing one or more of the following:

• Adjusting contrast, grey scale and brightness
• Using filters
• Cropping or compressing images
• Altering the number of pixels
• Cutting away lanes or zones
• Etc.
 
Alterations can be linear or non-linear. Manipulations are inappropriate, however, if they result in misrepresentation of the data, make the data impossible to be interpreted by others or, worse, lead to false conclusions.
 
Manipulation of images with the intent to misrepresent data is nothing less than falsification, a serious breach of scientific integrity.
 

VIB guidelines and recommendations

What is an acceptable/unacceptable scientific image manipulation?
The overarching principle is plain and simple: manipulations that lead to misrepresentation of the original data are unacceptable.
 
What does this mean in practice? VIB fully endorses the following four points as formulated by Rockefeller University Press and The Journal of Cell Biology:

1. No specific feature within an image may be enhanced, obscured, moved, removed, or introduced.
2. Adjustments of brightness, contrast, or color balance are acceptable if they are applied to the whole image and as long as they do not obscure, eliminate, or misrepresent any information present in the original.
3. The grouping of images from different parts of the same gel, or from different gels, fields, or exposures must be made explicit by the arrangement of the figure (e.g., dividing lines) and in the text of the figure legend.
4. Nonlinear adjustments must be disclosed in the figure legend.


Acceptable image manipulations

Certain adjustments such as background subtraction or using a filter or digital mask may be needed to extract information accurately from complex images. Reporting the details and logic of such manipulations when applied to images as a whole should resolve concerns about their use.
 
Leaving out certain parts of an image (e.g. leaving out one or a few non-relevant lanes or zones of a gel), or combining certain parts or whole images into one image may be acceptable, but these manipulations must be clearly mentioned and demarcated, preferable by using boxes that delineate the different parts of the image.

 
 
 
 
 
 

Inappropriate image manipulation (not acceptable)

Certain adjustments of image data are inappropriate even when they do not affect the interpretation of the data. Examples include adjustments of brightness/contrast to a gel image that completely eliminate the background (so the reader cannot tell how much of the gel is shown) or that obscure background smears or faint background bands. Another example is the splicing of images from different microscope fields into a single image that appears to be a single field.
 
 
 
 
 

 

 

 

 

Fraudulent image manipulation (not acceptable)

Adjustments of images that affect the interpretation of the data are fraudulent. Examples include deleting a band from a gel to ‘fix’ a negative control that did not work or adding a band to a gel to indicate the presence of a product that was not actually there. Other examples include adjustments of the contrast level of an image such as:
 Changing the contrast of an experimental image compared with a control image
 Changing the contrast of an individual panel in a time series
 Using different contrast levels in the original and newly made merged images
 
It is also not allowed to increase the number of pixels to a number greater than that of the original image. This results in the computer having to create data that were not present in the original. By doing so, the resulting image becomes a misrepresentation of the original data.
 
Caption image: In the right image Photoshop has been used to clean up the background of the original image. Close inspection of the left lane in the manipulated image reveals a repeating pattern, indicating that such a tool has been used.
 
 

Some further recommendations

In order to prevent inappropriate editing, we recommend the following:
• Treat images as data. The best file format for saving such data is the TIFF format. • Never edit or manipulate the original image. Editing should always be done on a copy of the image.
• The original image should be saved unchanged, preferably in an electronic laboratory notebook (ELN) system. Your immediate colleagues and especially your group leader should always be able to check the original image.
• VIB is planning to support researchers by providing tools for editing scientific images in the near future. They should be used in accordance with the guidelines for appropriate image manipulation.
• When images become part of a manuscript, all authors should review the images prior to their submission for peer review.
• Authors should report how image data were manipulated, even if the manipulations are considered acceptable practice, or state that image data were not manipulated.
 

Responsible VIB Research

The VIB guidelines on scientific image manipulation are part of the VIB Program for Responsible VIB Research. For more detailed information, please check the VIB Intranet.

 

 

 

 

 

 

 

 

 

  

Original Image of a blot.
 
 
 
 
 

Manipulated image. Lane 4 is removed because it wasn't relevant. A white dividing line clearly indicates the fact that this lane was removed.
 
 
Manipulated image. Contrast and brightness have been adjusted to such level that background and vague bands disappear
 
 
 
 
Fraudulent image manipulation. In lane 3 one of the specific bands has been removed using Photoshop.