Articles ~ Skeptics Corner ~ How to determine if a photograph was faked using an image editing program

There are many resources online claiming to have real photos of the supernatural. This is an attempt to find natural occurrences that might create or resemble a supposed ghostly picture. Of course this is not to say that no ghost photos are real, but a good dose of skepticism never hurts.

Many fake ghost photos are easy to spot. Unfortunately, some of the best photos look "fake" when you first glance at them. A solid working knowledge of a good computer graphics program such as Adobe Photoshop can be helpful. However it all boils down to anecdotal evidence. Even if you could replicate a ghost photo in photoshop or another image manipulation program, it is still going to boil down to a matter of "he said, she said".

Fortunately there are scientific ways to determine if an image was manipulated in a computer program. This article is a generalized scientific guideline for looking at photos purporting to show paranormal phenomena. The scientific field of photography analysis can be quite complex, so we are only going to go over the two easiest techniques.

To begin, we intentionally faked two photographs in a image editor, called the "white" ghost (photo 1) and the "shadow" ghost (photo 2) for identification purposes. The pictures are shown below and are thumbnailed. Clicking on them will open the full sized photograph in a new window. For this first example, you are going to need a program that can read EXIF files. A simple google search for "free EXIF programs" will generate several good results. As with anything, some programs will be better than others, especially if they are free, but EXIFPro is not a bad program to start with.

It is important to emphasize that when viewing a photograph on-line it does not necessary mean that the photo was an intentional fake. Even on this website, photographs are often brightened or have contrast adjustments made. other frequent changes are made to reduce the file size (for storage on our server) or changing the file name for easier cataloging. Any of these changes will reflect in the EXIF file and may even erase it.

The important thing for ghost hunters to understand is that it is important to keep the original photo (and its EXIF file) intact. We provide the original photos that we think are interesting in the research section of our website.

An intact EXIF can be used to counter claims of fakery but as stated above, it can be flawable. Older digital cameras may not even record EXIF data at all and it is very easy to accidentally erase it. Fortunately, we have other ways to analyze digital photographs.

Image analysis software

Retouching scientific photographs is a touchy subject, especially when changes and adjustments are not explained in articles and papers that use such images. Failing to fully explain enhancements and other changes in scientific photographs can even result in charges of scientific misconduct. While enhancing photos certainly has a role in science (when the enhancement is disclosed and explained), there is another kind of image software that is much more important to many scientists.

Instead of manipulating images, these programs analyze the information in images and provide a range of outputs. These sophisticated software packages can count blood cells, delineate tree rings, calculate the area of an object, grey-level (image intensity) histogram plot; 3-dimensional plot from intensity analysis; Sobel, Prewitt and Laplacian transformations; Morphology operations; Statistics, Histogram, Distance, Area, Perimeter, Particle analyses and much more.

The inclusion of an automatic Macro recorder here is a powerful tool - it's easy to use and will display all the analyses you repeatedly perform on images without the need for executing them over again. The results of the analyses may be easily exported to many programs such as spreadsheets (Excel and Quattro Pro), statistical packages (Unistat, Statgraphics), word processors (Word, Wordperfect) and Desk-top publishing packages (PagePlus, Aldus PageMaker). There is also ample opportunity to save such results in various files, as you might expect .superimpose plots of light intensity over a scene and so forth.

When you are equipped with a set of image files, you are nearly ready to do science as sophisticated as any professional scientist equipped with a $5,000 professional camera and a big government grant. All you need is a software tool to analyze your images.

Image analysis programs can be much more expensive than common image processing software. That's probably because the market is a good deal smaller.

Fortunately for amateur and professional scientists alike, this situation changed dramatically with the introduction of ImageJ, a powerful image analysis package written by Wayne Rasband at the National Institutes of Health (NIH). ImageJ is an open source program available to anyone. The program is written in JAVA and can be run on Microsoft, Linux and Macintosh operating systems that have a virtual JAVA engine.

ImageJ can be downloaded from the ImageJ homepage. Before downloading the program, be sure to review the various ImageJ pages and links to become acquainted with the program and to make sure it will run on your system. This step will also impress you with some of the program's applications.

It is impossible to cover all of the many features of ImageJ in this brief article, and not it's focus, so let's get back to the point and explain how to use it to determine if a photograph may be a fake.

One of the easiest ways to look at the surface plot of the photograph in question. Every pixel captured by the camera's CCD has a measured area with maximum intensity value of 255. The surface plot creates a 3-D graph of every pixel and its intensity value.

So, we generate a surface plot for each of our faked photographs (once again the images below are thumbnailed, click on them to see the full sized image).

By looking at the surface plots, a feature called "flat lining" becomes very apparent where the "ghosts" were painted into the image. Notice how it does not do it to the people in the photographs. Flat lining is caused by the image editor. When the photo analysis program analyzes the image, almost every pixel altered in the editor will read the same value regardless of the color used.

But what if we give the program more of a challenge?

To explain this I have also included the surface plot for the original unaltered photograph. When you look at the plot areas where people are, you will notice that the plot varies greatly in pixel intensity. This helps in determining that a certain figure or object is 3_dimensional. When a figure is pasted into a photograph in a image editing program, it creates a new layer which must be merged into the photograph. The merging causes the image to be embedded into the original which can easily be seen in the surface plot. Practicing with the program and experimenting with its features can give you a wealth of information that can used to prove or disprove the validity of that "unusual" picture.