The Secrets Of Infallible Image Watermarking

To provide infallible protection of your images before publishing them on the web is absolutely real, it's just enough to observe a number of simple rules:

Breaking the protection from the image should be economically unprofitable. The cost of restoration should be higher than the cost of the image, and then there will be no sense to struggle with protection.
Keep your watermark in secret. In case the image you use as a watermark becomes known to the malefactor, it will greatly simplify the cracking of the image.
Multi-detailed images are easier to protect.
A watermark should cover a considerable part of the image to avoid cropping. In order to preserve the presentable appearance, it is possible to make a watermark translucent.
Clients will be able to assess the quality of the image if it will be protected by a translucent watermark.
A watermark should be multi-detailed to make simultaneous automatic restoration of a great number of images impossible.

The application of a visible watermark is one of the most foolproof methods of image protection. This method is very flexible and has many options; therefore it is important to use it correctly.

A watermark replaces the points of a source image and it's the basic advantage of this method. There is no way to restore the source image, except for finishing its lacking parts. It's not always possible to finish the source image (for example, photos); only a professional artist can do this. And it is expensive.

The restoration costs money and when the cost of restoration exceeds the cost of the source image, nothing remains to the malefactor, but buy the image that you have.

Purpose

To make the automated restoration of image watermark impossible. To make freehand finish drawing the only way to restore the image.
To introduce the distortions into the source image as less as possible so that the potential customer could assess its quality, saturation and sharpness.

These two items contradict one another. The more the better part of the image is covered by a watermark, the more infallible the protection is while the presentable appearance of the image is lower (as a great number of details are hidden). And on the contrary, the less the watermark covers the image, the better the presentable appearance is and the protection is worse.

It is very important and difficult to draw a distinction between the presentable appearance and the infallibility. The only right measure is the cost of restoration. It is necessary for us to make the restoration of the image economically inexpedient: the cost of restoration should exceed the cost of the image. In this case it is easier to buy the image than to spend time on breaking the protection.

Framing

The simplest way "to restore" the image is to delete a part of the image with a watermark. If the watermark is installed incorrectly and occupies quite little place in the corner, the image will lose at cropping not so much: then the malefactor will take advantage of this method.


Fig. 1. Protected image	Fig. 2. Cropped image

For this reason it's very important to place a watermark correctly.


Fig. 3. Watermark in the center of the image	Fig. 4. Covering of the source image by a watermark

It is necessary to place a watermark so that its deletion could make the image unsuitable for any use. Placing a mark in the center is a very good variant, but in this case the presentable appearance is lost: the image in Fig. 1. looks better, than in a Fig. 3. However the latter is protected better. As a compromise variant, it is possible to increase a transparency of the mark and cover the whole image by it (Fig. 4.).

Translucent watermarks

Translucent watermarks are a way to keep the presentable appearance at a high level of infallibility. The source image is seen through the watermark, remaining protected and giving the user the possibility to assess the quality of the image.

Fig. 5.

This image is already well protected, and it is difficult to restore it. So the malefactor, most likely, will buy this your image. However, if lots images are protected by this watermark, the malefactor may try to isolate a watermark.

When there is an access to a source watermark and it is translucent, it can be deleted automatically. It is possible to isolate a source watermark from the image, but it's more difficult to do this if the mark contains many details (by the way, if a photo contains a lot of details, it is more difficult to restore it as well).

In this example the watermark contains very few details – our watermark is exposed. The program Visual Watermark has a special option « Noisy Watermark » which will add noise to the watermark and will increase its detail. The noise level can be adjusted with a slider: from 0 up to 100 units.


Fig. 6.

Fig. 7. Source watermark	Fig. 8. Noisy Watermark (20 %)

Detail

The higher the detail of the image is, the more difficult it is to restore it. The higher the detail of the watermark is, the more difficult it is to delete it.

When a source image is full of fine details, a finish drawing becomes impossible – so it is a hard-making process. As for high-detailed images (photos), only automated restoration, about which we spoke above, represents real danger to them.

Results

To provide infallible protection of your images before publishing them in the network is absolutely real, it's just enough to observe a number of simple rules:

Breaking the protection from the image should be economically unprofitable. The cost of restoration should be higher than the cost of the image, and then there will be no sense to struggle with protection.
Keep your watermark in secret. In case the image you use as a watermark becomes known to the malefactor, it will greatly simplify the cracking of the image.
Multi-detailed images are easier to protect.
A watermark should cover a considerable part of the image to avoid cropping. In order to preserve the presentable appearance, it is possible to make a watermark translucent.
Clients will be able to assess the quality of the image if it will be protected by a translucent watermark.
A watermark should be multi-detailed to make simultaneous automatic restoration of a great number of images impossible.