Eagle CAD Negative Photomask preparation and printing technique

Tools I used:

1. Eagle CAD 9.5.1 free.
2. Eagle ULP for SVG export: eagle2svg-1.3.ulp by xtitoris link: http://eagle.autodesk.com/eagle/download/1959
3. InkScape 0.92.5

Step BY step Process

Part -1

• Create or open an existing Eagle Board project.
• Go to Layer Settings in View -> Layer Settings
• In Visible Layers Window select only Top or Bottom Layer, Pads Layer, and Visa Layer to be Visible and click ok
• Then go to Run ULP… in files -> Run ULP. In the ULP window browse and select eagle2svg-1.3.ulp from your downloaded location.
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• In the new window select the place where you want to save and select Monochrome checkbox then click OK

Part -2

• Open Inkscape software, go to document properties and change the background color of the document to checkerboard background and then Import the newly created SVG file.
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• Select the imported SVG file then go to Filters -> Color -> Invert.
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• From the Invert window select Invert Lightness.
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• Now Draw a black color rectangle shape to the size of the imported image.
• Then place the white color board layer on top of the black rectangle shape to make it as background.
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• Now you have an inverted top layer of PCB for screen printing or for dry film photoresist etching process.