Here's a 3D printing project that's simple enough for grandma to enjoy, and fast enough to make all your holiday cards. Using a new in-browser JavaScript tool I've just made, you'll be able to take a digital photo and turn it into a halftone block printing plate with no 3d modelling experience, no signup, no big, slow download, and no carving. It goes like this.

1. Drag a photo into your browser*

2. Download your file

3. Send your file to a 3d printer

4. Ink your plate, and print away!

*Read: Chrome. Otherwise, you're in trouble.

TRY IT.

Step 1: Choose an Image

I thought landscapes and high-contrast photos would make the best candidates for a halftone / blockprinting project. WRONG.

What I found works best:

- Closeup portrait
- Smooth gradations of color / density
- Stay away from fine texture
- Stay away from landscapes

Scale is key. You want as many pixels as possible to be a part of the same object in your scene, which means that your photo is relatively close-up. If objects in your scene start to be smaller, they may only be one or two "dotscreen cells" wide, which means zero definition. Stick with something large, close, and smooth.

Still life paintings are probably ideal. I experimented with a couple of random charcoal drawings from Google image searches. They seem to work great (see image above).

Step 2: Generate the Halftone STL

Attached are screenshots from the entire process of creating and downloading a customized 3d printable block plate. There are just 4 steps.

1) Drag your image into the browser
2) Choose a dot screen (how "fine" your halftone should be)
3) Choose a plate size (small, medium, large)
4) Download the file, and print it

The web page does all the hard stuff for you. A few notes and tips:

1) This may challenge your browser. If you run out of memory, try a "coarser" dot screen.
2) The geometry is all closed (no "holes"), but it's not union'ed. This might cause problems for some printers, but the Object Connex 500 at our office handled it without even a warning.
3) The STL you get is ASCII, not binary. That just means it's larger than it needs to be. Shouldn't be an issue, but it's easier to make ASCII files from JavaScript.

Step 3: 3d Print Your Block Plate

TIPS:

1) Use a softer plastic material. Tango+ is good in Objet's series, ideal if you have access to an Objet Printer. See material discussion below.
2) Use the highest resolution you can find. Don't bother with a maker bot.
3) If you don't have access to a hi-res 3D printer, hit up Shapeways

Step 4: Block Plate: Material Considerations

Because block plates tend to be hard (linoleum, wood), I figured the hard plastic ("Vero White") would work well.

Not so.

Print Edge Quality Winner: Tango+
With the harder plastic material, small inconsistencies in the flatness of the top surface telegraph straight through to the final print. Compare the blue print above with the black one: the blue print came from a block printed on a hard white plastic, the black print came from a softer material called Tango+ Black. Note that the blue print has a number of vertical streaks: despite the high resolution of the objet printers, these lines from the print head cause major distractions in the resulting 3d print.

Ink Absorption Winner: Tango+
It also turns out that the hard plastic causes "globs" of printing ink to accumulate on the surface. Again, look at the blue and black prints of Einstein. The blue print has thick globs of ink remaining on the surface of the paper, where the black print came out much smoother.

Step 5: Prepare Blockprinting Materials

I bought a simple kit plus a "brayer", which is used to press the paper into the block print for an even print. These two items should get you through the whole process. You might want to buy some special paper for the occasion, too.

Kit: http://www.amazon.com/gp/product/B0027AGDWK/ref=oh...
Brayer: http://www.amazon.com/gp/product/B000Q60MM4/ref=oh...

Step 6: Ink the Plate & Print!

Blockprinting is pretty straightforward.

1. Squeeze a little ink onto your inking plate (the flat black thing)
2. Roll it smooth
3. Apply ink to your block plate evenly
4. Carefully place paper down on top of your inked plate
5. Press the paper down firmly using the brayer to get even transfer onto the paper
6. Peel the paper off of the plate

Check out the animated gif's! Google auto-awesome'd them for me (the animations were automatic). And they are, in fact, auto awesome. I couldn't believe it.

Step 7: Observations

- The prints from the plate made of a rubbery material (the black prints) were MUCH cleaner than the ones from the plate made of hard plastic.
- OOPS: everything is backwards! So I've fixed that in my web tool, even though the demonstration prints are backwards. The preview will be forwards, your downloaded STL will be backwards, your block plate will be backwards, and your final print will be forwards.
- Play with a bunch of different photos. You'll find a good one. Bad photos can make good block prints!