Photos to Pen & Wash

This instructable demonstrates a novel way of creating pen & wash outlines from photographs.

All you need is a Windows 11 computer and access to a CNC plotter such as that described in my instructable https://www.instructables.com/CNC-Plotter-1/

The “sketchpad” software for this project was created using Processing 4.4.10 which is free and open source.

Sketchpad saves your work to a file for plotting at a later date which is handy if you haven’t got a CNC plotter but know someone who has.

The software also talks to your CNC plotter if it is connected.

Images

1. The cover photo shows the original image, the traced outline, and the finished watercolor.
2. Fig.2 shows a garden seat, the traced outline, and the finished watercolor.
3. Fig.3 shows the partially completed tree outline.
4. The video shows the outline being printed.

The following items are required:

1. Windows 11 computer.
2. Processing software.
3. Universal G-code Sender. [1]
4. A cellphone or digital camera.
5. Access to a CNC plotter such as https://www.instructables.com/CNC-Plotter-1/ [2]
6. Graphite pencil [3]
7. Watercolour paper
8. Watercolor paint
9. Watercolor brushes

All of the software is free and open source.

Assuming that you already have the consumables, the estimated cost of this project is NIL providing you have access to a CNC plotter.

Notes

[1]

G-code stands for “geometric-code”

[2]

This plotter can accommodate A3 paper (and larger) by using longer rails to separate the motors.

[3]

The pencil lead determines the darkness of your outlines:

1. HB = light
2. 2B = medium
3. 8B = dark

Three software packages are required all of which are free and open source:

1. Processing 4.4.10 for running the sketchpad software that I created.
2. “sketchpad.pde” This creates the outline and runs under Processing 4.4.10
3. Universal Gcode Sender For plotting you outline at a later date.

Processing 4.4.10

1. Download and install Processing 4.4.10 from https://processing.org/.
2. Installation instructions are provided by this site.

Processing Sketch

1. Download the attached file sketchpad.pde
2. Copy the contents of this file into a fresh Processing sketch using a text editor.
3. Save this sketch as “sketchpad” (without the quotes). This will create a folder within the Processing folder called “sketchpad”

Universal Gcode Sender

1. Download and install Universal Gcode Sender from https://winder.github.io/ugs_website/

Copy the attached file “background.jpg” to your C:\..\Documents\Processing\sketchpad folder. [1]

There should now be two files in the sketchpad folder:

1. background.jpg ... the image you want outlined
2. sketchpad.pde ... the software that creates the outline

Open Processing.

Select File/Open/sketchpad/sketchpad.pde

Click the left-hand "run" button. An image similar to that shown in fig.1 should appear.

The three buttons control the pen

1. "Pen Up" raises the pen
2. "Pen Down" lowers the pen until the next Pen Up
3. "Close" ends your session and saves your work to a file with a prefix "session.."

Click the Pen Down button and then click each corner of your image. A border will appear as shown in fig.2. If your plotter is connected this outline will be drawn as you click around the perimeter.

Click the "Pen Up" button before repositioning your pen otherwise an unwanted “snail-trail” will appear.

Now click "Pen Down" and start clicking around another object in your image as shown in fig.3. Always click "Pen Up" when you have completed an outline.

Click "Close" when you have finished and a g-code file starting with “session_...” will appear in your “sketchpad” folder. If your plotter wasn’t connected to your computer while you were tracing the outline, you can sent it to your plotter at a later date using Universal G-Code Sender.

Note

[1]

“sketchpad” only accepts images called “background.jpg” for outlining.

If you wish to use your own image simply make a copy and rename it “background.jpg”.

Method

Connect your plotter to your PC and apply power.

Launch UGS (Universal G-Code Sender). The opening screen is shown in fig.1

Click the “connect” tab. This looks like an orange extension cord with plugs. Click the COM tab if you get the error message shown in fig2. and select the correct port for your computer from the drop-down list shown in fig.3

Click the “connect” tab again and you should see the following screen. You may have to raise the “console” bar to see this message.

We now need to select our file for printing.

Click File/Open and navigate to your "C:\..\Documents\Processing\sketchpad" folder.

Click the “session” file you just created ... a screen similar to that shown in fig.4 will appear.

In this case it is the partially completed file that we started earlier.

An explanation of the screen layout:

1. The blue lines in the right-hand image represent the path your pencil will trace.
2. The yellow pointer represents the pencil

The screen above the “console” is the g-code you created.

Finally ... click the start button and your plotter will start to move.

This instructable demonstrates a novel way of creating pen & wash outlines from photographs.

All you need is a Windows 11 computer and access to a CNC plotter such as that described in my instructable https://www.instructables.com/CNC-Plotter-1/

The “sketchpad” software for this project was created using Processing 4.4.10 which is free and open source.

Sketchpad saves your work to a file for plotting at a later date which is handy if you haven’t got a CNC plotter but know someone who has. The software also talks to your CNC plotter if it is connected.

Plotting at a later date requires Universal Gcode Sender from https://winder.github.io/ugs_website/. This software is also free and open source.

Assuming that you already have the consumables, the estimated cost of this project is NIL providing you have access to a CNC plotter.

Click here to view my other instructables.