Changing Colors

[tomtom]

Dear Forum,
I have a picture with a secret message that you can only see if you look at it through a red filter.
I would like to change the image so that the message remains invisible to the naked eye, but becomes visible through a blue filter.
Is there a way to do this?
Thank you very much.

[Tas_mania]

When you say

Quote: only see if you look at it through a red filter.

do you mean an optical filters like red glasses or something else?

[Ofnuts]

Use Color > Components > Channel mixer to swap the red and the blue:

   

[Tas_mania]

I followed ofnuts suggestion and it worked. I altered most slider to see the code. 
'01 01 TEST 01'
eh, eh ,eh.

   

[tomtom]

Thanks for your help so far.
Please excuse the fact that it was not quite clearly formulated. By the red filter, I mean something like red glasses.
With the red glasses, you can read the words I O I O I TEST I O I O I. You can't see anything with blue glasses.
My aim was that after changing the color, the words are still invisible to the naked eye, but then become visible with blue glasses. Red glasses would also not be able to reveal the words after my desired change.

[denzjos]

Also a solution : G'Mic-Qt / Ian Fergusson / Repair / Grey Descreen