You might have noticed that there were a few times the images that I attached to this blog’s article has a watermark. By default the images has no protection at all and anyone can use it and claim that it was taken by them. So a lot of people resort to visible watermarking, a method of embedding information into an image that can clearly shows who is the owner of the image. Depending on the complexity of the image, sometimes it is nearly impossible to remove the watermark from the picture. Where you place the watermark is also important. If you put a small logo watermark at the corner, it can be easily removed by cropping off that part. Best is to put a watermark diagonally across the image BUT professional photographers hated that because it covers up the area which they are trying to focus.Another method of protecting your image is to use invisible watermarking. It is the same as above by embedding an information to the image except that it cannot be seen. One software that can do this is SignMyImage. SignMyImage allows you to insert your sign to the image and allows you to check if any image is signed or not. The sign can consists of letters, capitals, numbers, dashes and can be up to 10 characters long. Typical sign looks like “Raymond-CC”.
SignMyImage adds your sign directly to the image data. It modifies picture intensity at few places slightly. The modification is so gentle that it is invisible for a human eye. SignMyImage doesn’t use EXIF(or other tags) or stream properties of image files to sign the image. SignMyImage doesn’t allow to sign already signed images and the best part is the signature stays detectable after jpeg compression, scaling and cropping or for example PrintScreen&Paste.
Try comparing the 2 images below and see if you can spot any difference. The left one is original image and the right one is the signed image. I bet you can’t find any difference at all or notice any invisible watermarking.
Embedding an invisible signature using SignMyImage is very easy. All you need to do is load an image to the program, click Sign at the menu bar and select Sign Image. You get to enter your sign which must be less than 10 characters. When the signing has completed, just save the image to a new filename or you can replace the existing one.
The only drawback for SignMyImage is its shareware that cost 14,99 Euros. You can use it for free to watermark images with invisible signature but you cannot use the batch processing feature and every watermarked image will be signed by a visible stamp to right-bottom corner. An idea to overcome the stamp is to maybe add a few pixels of empty space at the bottom so that the program stamps it at an empty area which can be cropped. Paid user also gets to access the Image Spider. Image Spider is a web crawler, that searches through whole internet for signed images. If it finds a signed image, the owner of the image will be noticed.
