Conquer Club

Do you need to cite the sources of the textures you use? What about pictures you use? Has anyone had any problems with copyright?

Well... I guess it depends on how you use them... Will it be possible to recognize the texture from your image? If yes, then it's probably best to make sure it's free to use.

However, in most cases, when you use a grunge layer or a texture, they are so ambiguous, that you can't tell one texture from another... So it would be impossible for someone to prove that you have used his texture file for your image.

Still, it's always best to use non-copyrighted material. Just to be sure. I make my own textures, and I'm starting to figure out how to make decent grunge layers as well...

As for pictures, any pictures that you use must be non-copyrighted, since they are clearly recognizable from your image. There are loads of stock images that can be freely used online.

And loads of images with watermarks through them...

RedBaron0 wrote:And loads of images with watermarks through them...

meh, I never had any problems finding stock images without watermarks.

It is not likely to occur in the kind of images/textures/grunge that CC mapmaker use, but it is possible to embed a watermark in a digital image that is essentially invisible but can be recovered in order to establish the provenance of that image. So just because you can't see a watermark, doesn't mean there isn't one.

ender516 wrote:It is not likely to occur in the kind of images/textures/grunge that CC mapmaker use, but it is possible to embed a watermark in a digital image that is essentially invisible but can be recovered in order to establish the provenance of that image. So just because you can't see a watermark, doesn't mean there isn't one.

You mean by steganography?

Those kind of watermarks are essentially destroyed when a texture is applied in the image with the multiply blend mode. The watermark may be found in the layered image, but not in the final .png or .jpg image.

If you want a longer explanation:

Steganography uses the least important bits of the image data (usually, the 2-3 lowest bits in each RGB value) to store hidden images inside other images. When you apply the grunge layer, you are usually using multiply blend mode, which multiplies the RGB values by the RGB values of the layers underneath the grunge layer. Opacity is also reduced, and this screws up with the RGB values in such a way that the data hidden in the least important bits is destroyed. Thus any watermarks hidden in grunge layers won't be visible in the final image.

As for images other than grunge textures, there are softwares & plugins for finding and removing steganography images. However, the same principle applies to these images: if the images are applied with low opacity or different blend modes, the steganography images will be destroyed.

natty_dread wrote:

ender516 wrote:It is not likely to occur in the kind of images/textures/grunge that CC mapmaker use, but it is possible to embed a watermark in a digital image that is essentially invisible but can be recovered in order to establish the provenance of that image. So just because you can't see a watermark, doesn't mean there isn't one.

You mean by steganography?

Those kind of watermarks are essentially destroyed when a texture is applied in the image with the multiply blend mode. The watermark may be found in the layered image, but not in the final .png or .jpg image.

If you want a longer explanation:

Steganography uses the least important bits of the image data (usually, the 2-3 lowest bits in each RGB value) to store hidden images inside other images. When you apply the grunge layer, you are usually using multiply blend mode, which multiplies the RGB values by the RGB values of the layers underneath the grunge layer. Opacity is also reduced, and this screws up with the RGB values in such a way that the data hidden in the least important bits is destroyed. Thus any watermarks hidden in grunge layers won't be visible in the final image.

As for images other than grunge textures, there are softwares & plugins for finding and removing steganography images. However, the same principle applies to these images: if the images are applied with low opacity or different blend modes, the steganography images will be destroyed.

Yes, steganography would be the word. I recognized it when I saw it, but it has been so long since I considered such things that I had forgotten there was a word for it. (Trust me, being the pedantic logophile that I am, I would have used the word had I remembered. ) Clearly, from your descriptions of tools now available, the state of the art is far advanced from what little I knew.

Hehe... this gives me an idea... I could hide all kinds of neat stuff in my maps...

natty_dread wrote:Hehe... this gives me an idea... I could hide all kinds of neat stuff in my maps...

And spend tons of time putting things in that no one ever sees?

captainwalrus wrote:

natty_dread wrote:Hehe... this gives me an idea... I could hide all kinds of neat stuff in my maps...

And spend tons of time putting things in that no one ever sees?

Hardly tons of time, just 2 clicks with the mouse...

natty_dread wrote:

captainwalrus wrote:

natty_dread wrote:Hehe... this gives me an idea... I could hide all kinds of neat stuff in my maps...

And spend tons of time putting things in that no one ever sees?

Hardly tons of time, just 2 clicks with the mouse...

oh, I didn't really read what you posted before, I just saw that it seemed kinda complex, so I figured it would take time.

Well, I have a plugin for paint.net for detecting and adding steganography to images. It only supports 1-bit b/w or 3-bit colour steganographies, but that's fine, at least it doesn't screw with the image too much.

natty_dread wrote:Well, I have a plugin for paint.net for detecting and adding steganography to images. It only supports 1-bit b/w or 3-bit colour steganographies, but that's fine, at least it doesn't screw with the image too much.

I guess the steganographs wouldn't appear when you use BOB to reduce the map opacity, eh? Too bad, really.

ender516 wrote:

natty_dread wrote:Well, I have a plugin for paint.net for detecting and adding steganography to images. It only supports 1-bit b/w or 3-bit colour steganographies, but that's fine, at least it doesn't screw with the image too much.

I guess the steganographs wouldn't appear when you use BOB to reduce the map opacity, eh? Too bad, really.

Yeah, any time when you screw with the colour values in such a way that it affects the least important bits of the RGB, it will destroy the steganographs.

However, I'm not sure how BOB works, does it modify the image file itself or does it just screw with how the image is displayed? Because, anyway, you would need to download or save on your hard drive the image file, so that you could decode it to reveal the hidden steganography. On the other hand, there are probably firefox plugins made which can decode steganographs "on the fly"... I'm not sure, but you can search for one.