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increase thickness in line drawings

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A little background on what I am attempting to accomplish. When my 5 year-old grandson makes a drawing, I am tasked with scanning the picture, cleaning it up, resizing it, converting it to an embroidery file so that my wife can use her embroidery machine to sew the drawing on a "curtain" for display and memories.


I use paint.net (obviously) to clean up and resize the drawing; however, I am very new to paint.net. I understand most of the basic tools but I am very inexperienced at some of the more powerful features.


He recently drew a picture of a flower (attached); however the size of the lines in the drawing are too narrow to embroider well. They are about a brush width of 25 and need to be at least 45 for the embroidery to look good.


I have tried a couple of methods both of witch kind of work but are very time consuming.

Method 1 was to simply trace around his drawing with the paintbrush set to a width of 45. This keeps the general shape of his drawing but loses a lot of his originality

Method 2 was to duplicate his drawing in a separate layer, shrink it a bit, then in another layer enlarge it a bit and finally move parts up and down and left and right to enlarge the shape.


I was hoping someone could tell me how to accomplish this task in a better manner. I am assuming the instruction might be more advanced than I am so please give me as much detail as possible.


Thank you very much


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One idea that might be worth a try:


Run Effects>Noise>Median, setting the Radius to 2, and leaving the Percentile at 50.

Repeat until the lines are wide enough.


(I can't quite say off hand why it widens the lines, but it does.)

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You can use a plugin called 1px Expansion which is part of Dpy's Plugin pack.


Here is a comprehensive guide on HOW TO INSTALL PLUGINS on Paint.NET.


You might have to choose only the specific .dll called "pxEexpansion.dll" if you want to install only that plugin, however the rest of them will be useful in other fun things.


Now, open the image of your child's drawing on Paint.NET. Choose the Magic Wand and set its flood mode to "Global". Click on the white blank area and press Delete on the keyboard. This should clear out all of the white areas and make them transparent.


Go to Adjustments>>Hue/Saturation and from there, lower the lightness to -20. This is optional. This will work if you want to colors to be heavier though. 


Then go to Effects>>Distort>>1px Expansion which should now appear in there. It will thicken the lines. For your image, I suggest using 1px Expansion twice. You can now save the image as .png if you want to retain the transparency or as a .jpg if you're fine with the white background again.

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My suggestion:


1. Remove the white background with AlphaSpace with White selected and a Tolerance of 47.


2. Expand the edges with @MJW's Edge Expander. When installed this can be found under Effects > Object. Use Max Distance of 11, Fade Rate of 0 and Opacity Threshold of 149.


3. Run Effects > Noise > Median with Radius 12 and Percentile at 25 (or thereabouts).


Before and after...



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Thanks for all of your help, I tried each of your methods and then picked from each. I learned so much.


A couple of comments about each if I may:

MJW- Median didn't seem to do anything at first. I then realized that I had resized my working image so that it would upload, after I reduced the colors to just 6, your technique seemed to work

Ishi-I loved that 1px Expansion. At first it didn't seem to do much but when I zoomed in it is pretty cool that it increases everything by 1 pixel in each direction (I think). It did seem to do a little distortion in the purple and of course by increase size got some of his blue dots a little out of position, I just moved them a little afterwards

Ego Eram Reputo-Thanks for suggesting the Alpha Space plugin, it works very well. I liked edge expander except I kept losing the yellow center of the flower with it.


Again, thanks for all of your help and I appreciate how thorough your instructions were.  I hope my experience will help someone else that faces a similar issue.


One of the most valuable things I learned is that zooming in (all the way in) really lets you see what these plug-in do.






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