Add invisible watermark to pictures

Add invisible watermark to pictures.

I thought this was interesting, so I posted it.

Pictures with this invisible watermark will disappear when saved in a lossy compression format (such as jpg).
There is a certain resistance to the following conditions.

  1. Cut.
  2. Graffiti.
    In other cases, I didn’t test it, because I don’t think the invisible watermark that disappears when saved in a lossy compression format (such as jpg) can protect the author.

It would be nice if krita could provide an invisible watermark option with the author’s name when exporting images in the future.
This invisible watermark needs to be saved in a lossy compression format (such as jpg), which can still exist after various image processing, and the image with the invisible watermark cannot show any visible changes to the naked eye.

How to add invisible watermark:

  1. Open the picture you want to add invisible watermark with krita.
  2. Use G’MIC filter–>Fourier Watermark to add invisible watermark.
  3. Export as png.

Check out the hidden watermark added using this method:

  1. Open the png you just exported with krita.
  2. Use the G’MIC filter → Fourier Transform to view the added invisible watermark.

According to the notes of Fourier Watermark it should be Fourier Analysis that reveals the watermark, not transfoorm.

The same png with an invisible watermark looks like this in Fourier Analysis…

Then either the note is wrong or the filter. This should be reported. It’s an interesting filter.

I have reported this bug.
459526 – Invisible watermarks added with Fourier Watermark cannot be viewed in Fourier Analysis. (

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It’s the Fourier Transform that reveals the watermark and I think that is a problem with the explanatory comment in the GMIC filter.
Shouldn’t this be reported to the GMIC developers.

I’ve just tried to remove/mask a Fourier watermark and it makes a total mess of the image so it seems to work well :slight_smile:

Can’t the “G’mic for Krita” of krita’s bug category report this kind of bug?
I didn’t know that before.

Can you help report it to G’mic?
I can’t use github right now. (The network I use sometimes fails to open github.)

Like I said earlier, the user just needs to save as jpg again and the watermark is gone.
So I don’t think it’s practical enough.
Now many websites and social software like lossy compressed pictures…

There is a particular developer who has deep knowledge of GMIC but I’ve forgotten their name. @tiar would know who is involved there.

Yes but in a case of someone doing this to your work and claiming the work is their own, you can provide the high resolution .png with watermark and if it comes to a serious argument, you can show that you have the original .kra (or other application) file with all the development layer structure in it.

In the past, i’ve found and removed simple ‘hidden’ watermarks from good quality images but that Fourier watermark is very good.

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Did you actually apply the filter?
Seems to be merely an issue with the preview here, Analysis and Transform give exactly the same result layers for me.
The only difference of the filters seems that Transform for some reason ignores the selected layer and processes all layers instead.

@Lynx3d are you asking @Eranthis_stellata or me?

I think you are right, I saw the watermark after applying Fourier Analysis.

I’ve just tried it again and the Fourier Analysis does not show the watermark clearly on the preview but it is visible on the preview of the Fourier Transform.
On the final processed image, the watermark is more clearly visible on the Tranform than on the the Analysis.