Introduction: Enhance Your Image When Reverse Laser Engraving on Acrylic Sheet
I developed this easy way to enhance your high contrast images, laser-engraved onto the back of clear acrylic plastic sheet at Makerplace in San Diego, CA using their 100 watt Hurricane laser. You can engrave any kind of image. For this demonstration I'll use a portrait. What sets this technique apart is the use of black and white paint on the backside of the acrylic sheet to dramatically intensify your high contrast images.
Here's what you'll need:
• Your image
• Adobe's Photoshop or other image authoring tool
• Access to a Laser cutter
• Flat black and white paint (I use spray paint for the black as it coats evenly and for the white, Liquitex's heavy body acrylic titanium)
• A sheet of acrylic
Prepare the Image File
I use Photoshop CS4 as my image authoring tool. You'll want to do the equivalent in whatever tool you use.
Step 1: Turn Your Color Image Into Grayscale
• Image > Mode > Grayscale
Step 2: Turn Your Grayscale Image Into a Bitmap
• Image > Mode > Bitmap (Output:60; Method: Diffusion Dither)
Step 3: Invert Your Bitmap Image
• Image > Adjustment > Invert
Step 4: Flip Your Inverted Image
• Image > Image Rotation > Flip Canvas Horizontal
• SAVE AS Bitmap file (.bmp)
Step 5: Prepping the Substrate
• Peel the protective film off of one side of your acrylic sheet. Leave the protective layer on the other side for now.
• Spray the acrylic with an even coat of flat black paint. Let it dry
• Spray the acrylic with a second even coat of flat black paint and let it dry.
Step 6: Settings to Engrave the Image
• Place the painted acrylic sheet paint side up on the bed of your laser cutter.
• Focus the laser for the thickness of this material.
• Import your bitmap .bmp file
• Engraving on acrylic works best when the process is done at high speed and low power. On the 100 watt laser at Makerplace, my settings were Speed: 900, Power: 55 and the Span Gap at .085
Step 7: Engraving the Image
• When the laser is done, remove the acrylic sheet from the machine and clean it with a soft paper towel to remove any residue created by the engraving.
Step 8: White Fill the Engraving
• Place your acrylic sheet engraved side up on your work surface
• Paint the acrylic with an even coat of white paint (I'm using acrylic titanium white)
• Let it dry
Step 9: White Fill -- Second Coat
• Paint the acrylic with a second even coat of white paint.
• Let it dry
Step 10: Voila!
It's that easy. Cut to size, peel the protective film off the front side and your stunning high contrast image is ready for framing.
Thank you Makerplace for providing the space, tools and support in developing this novel idea.