The Joy of Aluminum Foil Lithography

This is a lightweight version of PCB etching. Fat (or other e.g. sharpie) as the resist, aluminum foil instead of copper clad board, and cola as the etchant.

If you like this process and are into electronics, you should check out the process of creating your own printed circuit boards at home!

This looks like a lot of fun, but would it really hurt to link to the actual video, rather than a rabbit hole of links and blog in another language?

It feels like "we did this cool thing and took some photographs, but couldn't be bothered to actually write it up"

Here's a video of the same process (but using vinegar for the acid instead of soda) that doesn't cost $8: https://youtu.be/tXaimUkCVU0

This is strikingly similar to the process used in modern offset printing. As a young child, I grew up in a family printing business, and though I didn't learn all the details (I didn't really have much interest in the printing side of the business and spent most of my time in the then still very early digital prepress playing with the computers).

My earliest memories of it were marked by specialists doing digital typography on specialist computers, one monitor was a green-screen where some kind of markup was entered and the other screen was a raster monitor where the output was rendered. Each block of text was "printed" on photographic paper, cut and then sent to the "layout" department where it was taped or wax adhered to a page. (If this is hard to picture, imagine taping each block of text from this page [1] onto another piece of paper in order to layout the entire page.) The process looked a bit like this [2]

Then the final page was photographed in a photography room and the negative developed. On occasion a photographic "proof" would be developed to show the final page layout and make sure there weren't any artifacts from all these tiny little pieces of paper that were used to make up the text blocks.

Then the negative was used as a lithographic mask to "burn" the image of the page onto a metal sheet which then went through some kind of chemical bath to etch the image onto the sheet.

From that point the process was basically what's in the rest of this video [3]. And one more [4]

My parents ended up selling their company in the early 2000's because the cost of going "fully digital" from pre-press to print was just too expensive. At that time, the process had completely eliminated the tape and wax steps and the layout was being done entirely digitally in software, then printed onto regular paper which was then sent to film. The rest of the process was simply unchanged.

Big competitors had invested millions of dollars into equipment which apparently was capable of eliminating parts of the lithography process and color separated artwork could go almost directly from the pre-press department to paper. According to the videos I've linked to, the industry is now using laser etching to etch the image on the plates.

Many years later, this knowledge became useful when, in another setting, I was being interviewed by a gentleman with deep experience in microprocessor lithography and we hit it off when I mentioned my family's business and the lithography process we used in printing. Nothing so exotic as what's used in CPU production, but the basics are almost exactly the same. There's been some great videos about CPU lithography posted here recently. Here's one of them [5].

The guys who actually did the printing were an interesting sort. Small businesses being small businesses, we needed cheap help. So my family first started hiring Vietnamese immigrants escaping right after the war and training them. When that ran out, they eventually switched to a variety of people, many of whom were ex-cons. I learned a tremendous number of life-lessons from watching those guys, many of whom ran presses as artists, on how to and how not to wreck my life. The guys who were reliable were worth their weight in gold. The ones who weren't suffered from an unimaginable litany of self-imposed life problems, mostly drug or alcohol related.

At any rate, thinking back, this is really how I got my start into computers, hanging out as a kid in the prepress department. Some more to read [6]

1 - https://marketplace.canva.com/MABXLyRjyco/3/0/thumbnail_larg...

2 - https://3v6x691yvn532gp2411ezrib-wpengine.netdna-ssl.com/wp-...

3 - https://www.youtube.com/watch?v=5LMU-zB8Sro

4 - https://www.youtube.com/watch?v=pNZb7CXUjs0

5 - https://www.youtube.com/watch?v=NGFhc8R_uO4

6 - https://en.wikipedia.org/wiki/Offset_printing

Beautiful and so accesible, really want to try this. Also it amuses me that the aluminum is etched with Coke. Polar bears shouldn't give that to their babies!

Very neat!

I'm slightly confused what the oil is doing though?

Aluminography.

It can't be lithography sensu strictu if you're not using stone.