My problem: I wanted to paint a line drawing with color. This drawing is at level 1. The color should be at level 2. So that the drawing remains visible. But on the 2nd, no colors were visible. I did not lock. Where is the mistake? Thank you

Is the drawing on a transparent layer or on a white layer?
If it is on the white layer you can use either multiple mode or to remove the white "color to alpha" filter. Then you would need to add one more layer at the bottom of all with white color.

How does the multiple mode work? AND remove the filter "White color to Alpha"?

@michaelstoltz Can you post a link to a full screenshot of your image? This will give a better idea of your situation and image structure.
Even better, you could use a file sharing service to provide a download link for your .kra file so that it can be examined.

Can I send it as a zip format? kra format are not provided.

Yes, if you want to put it in a .zip archive then I could extract the .kra file, no problem.

So here's the picture I'm having trouble with. I want to paint this. But without changing the SW image.
Hier der Link: BurgKriebstein_001.zip

https://www.file-upload.net/download-13 ... 1.zip.html

I extracted your .kra file and opened it with no problems. You have black lineart on a white layer so the easiset way to put colour on this and still see the lineart is to have the colouring layer above the lineart layer and use the Multiply layer blending mode for the colour layer.

Here it is: https://i.imgur.com/XsWNCyj.png

The colour layer is multiplied by the lineart layer underneath so: colour x black = black and colour x white = colour
This is maybe the simplest technique if you have black lineart on a white layer and want a single colour layer over it.

The 'colour to alpha' method is more complicated and uses the Filter -> Colors -> Color To Alpha function, applied to your lineart layer.
This will convert the colour white (by default) to transparent but you can choose any colour to be converted to transparent.
This will give you black lineart on a transparent layer. This has more flexibility and then the lineart layer can be placed on top of any arrangement of colour development layers underneath it.

Thank you very much for the help.
This to be multiplication only a crutch. I remember it was easy to paint such pictures with layers by switching layers.