How do I reproduce this coloured highlighter painting effect?

[deepblue92]

So I was using Paint.Net and suddenly this started happening.

Despite there being only one layer, all Paintbrush / Line Draw / Any colour Input will not 'Overcolour' but instead 'Recolour' the image. (You can still see the image through the red paint). 

 

So, how do I replicate this? It seems like recolouring, but it works for any colour. Kind of like 'Highlighting', but without using additional layers and messing with the Transparency. 

 

I've tried googling it, but every result implies the Recolour Tool which is not what this is. 

 

Any help would be GREATLY appreciated. 

 

 

[Tactilis]

Welcome to the forum @deepblue92.

 

54 minutes ago, deepblue92 said:

So I was using Paint.Net and suddenly this started happening. Despite there being only one layer, all Paintbrush / Line Draw / Any colour Input will not 'Overcolour' but instead 'Recolour' the image. (You can still see the image through the red paint). 

You probably changed the Blending Mode to Overlay

 

 

[deepblue92]

Thank you thank you thank you thank you!

[Tactilis]

Looking more closely at your picture @deepblue92, it is more likely that the Blending Mode you had set was Multiply, rather than Overlay.

 

Try them both to see the difference. There's a description of the Layer & Tool Blend Modes here https://www.getpaint.net/doc/latest/BlendModes.html

 

Also, see also this topic for the usefulness of the Multiply mode as a highlighter pen https://forums.getpaint.net/topic/124445-how-to-highlight-text

 

 

 

1 hour ago, deepblue92 said:

So I was using Paint.Net and suddenly this started happening.

BTW, you probably switched from Normal to Multiply by accidentally clicking once on the Blending Mode control in the toolbar (rather than using its dropdown arrow). Each click changes to the next mode and Multiply comes immediately after Normal.