Convert pencils to non reproduction blue

[KCopper]

How do I change the color of linework to non reproduction blue? Specifically for printing digital artwork to apply inks to and then rescan without copying the original pencil work. If this is covered somewhere please give me a link. I tried to find it before asking.

[MJW]

Assuming you're starting with a black-on-white drawing, here's another method.

 

Add a lower layer and fill it with the color you want to make the lines.

Set the blending mode of the upper layer (the one containing the drawing) to Screen.

Merge the layers.

 

EDIT: Changed blend mode to Screen from Additive as a result some experimenting done in response to welshblue's follow-up comment.

[KCopper]

Isolate Line Art sounds like it will do the trick I am not sure how to integrate the plug in to paint.net. I downloaded file from provided link, extracted files, selected application, opened with paint.net and selected run, then got the error message that image was not compatible with this setting. How do I load a plug in?

 

[Pixey]

Here is How to install Plugins.  Be aware that you must choose between the Classic Download of paint.net, or the store bought version:

 

https://www.getpaint.net/doc/latest/InstallPlugins.html

 

 

[KCopper]

Thank you Pixey, found the install plug in instructions shortly after I asked the question. Very prompt response, I have successfully loaded my new plug in.

[KCopper]

Is Cyanotype another plug in? Now that I have Isolated the line art of the drawing I don't have the foggiest on how to get the the light blue. The sepia adjustment does what I imagine I need in the correct hue of blue.

[MJW]

9 hours ago, welshblue said:

That works well on simple sketches but something with a lot of detail/shading  can sometimes lose some qualities

 

After experimenting with it, Screen blending mode seems to work better than Additive.

[NinthDesertDude]

Without Plugins

1. Adjustments -> Sepia

2. Adjustments -> Hue/Saturation

 

Works because it's a grayscale image. Sepia gives it color, hue/saturation can adjust it to blue and tweak as needed.

That's it.

[KCopper]

Using Sepia then hue/saturation I was able to get great manipulation of color of line work. This method should work well for clean professional pencils. Coming from my own sketchbook I need to clean up the background; scanning in greyscale I get tone at the edges of my paper because of the thickness of the book and/or the quality of my scanner. Two things happened. 1, with Isolate Line Art it seems like I lose the ability to use Hue/Saturation, only lightness affects any change. Sepia does not appear to do anything either. 2, when placing my pencils over a second layer of white background I still get all the tone present at the edges of the page. I read the help on layers to get a foundation, but I am missing something about Isolate line art and/or Layers.  I am using the print preview to get an idea of final results. Ideally I want to clean up my sketches and then convert the greyscale to the light blue. Anymore thoughts?