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!
I used to go through the trouble of etching boards at home working with fairly nasty chemicals long ago. However the ease, speed and low cost of ordering PCBs nowadays means I can no longer justify to myself the time, trouble and danger especially with a kid in the house. Much better to get a prototyping shop to do it and send you.
At least with copper, you can also etch using vinegar and salt. I've done that a couple of times when I didn't have ferric chloride, and while it's slow it works just fine.
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]
That's very cool, I'd not heard of offset printing before.
It's a shame your family had to sell their business, as from what you mention it sounds like not all of the printing method changed.
I was wondering with the kitchen method, how you'd get a photo onto the foil, but as you mention a laser could be used. One thing I was slightly confused about, is, is it always necessary to use a coating on the aluminium for that approach.
I guess you could also coat the foil with the photosensitive emulsion you use for PCBs too, and then etch that.
Yeah, I guess I omitted that step as I'm not entirely sure how the actual lithography was performed. I remember a large "camera" where the negative would go into the top and the sheet would lie underneath. It looked vaguely like the reverse of an old acetate overhead projector.
How the image was etched in that process I simply don't remember, but I do remember the sheet going through a number of chemical baths and washings (and being reminded to stay clear of the chemicals as a child).
So there may have been some phase where the sheet was treated with a photosensitive chemical before going into the camera, I simply don't remember the detail.
This link [1] seems to have some details.
It looks like the plates run for a little over $1/plate for the smaller ones. [2]
Guessing it was something like an Agfa photostat camera. We had one of those at my first job. We used it both for making camera-ready art for ads (we were a tiny business) or positive film to send off to the PCB house to get boards made.
IIRC, the film was standard Kodak 8.5x11 size negatives and the processing was pretty simple. I would do everything from initial tape & wax puppets to the final artwork. Not what I expected to be doing in my first engineering job, but it was fun.
I took a printmaking class sometime later. I think the litho "stone" is made photosensitive and etched, but that aspect of the process is fuzzy. Most of the class was about positive prints and I spent most of my time doing intaglio and lino block 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!
The process of printing a lithograph on a hard,
flat surface; originally the printing surface
was a flat piece of stone that was etched with
acid to form a surface that would selectively
transfer ink to the paper; the stone has now
been replaced, in general, with a metal plate.
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!
I used to go through the trouble of etching boards at home working with fairly nasty chemicals long ago. However the ease, speed and low cost of ordering PCBs nowadays means I can no longer justify to myself the time, trouble and danger especially with a kid in the house. Much better to get a prototyping shop to do it and send you.
You can use sodium hydroxyde as an echtant. It doesn't turn everything it touches into stickiness like cola does.
At least with copper, you can also etch using vinegar and salt. I've done that a couple of times when I didn't have ferric chloride, and while it's slow it works just fine.
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"
This is the end of the rabbit hole: http://www.atelier-kitchen-print.org/category/video/
Thank you so much for linking this site! Great for school/students projects! Real Hacker Stuff!
If you read a bit further, they will share all the details in a book (written in English) for $8. They are not going to get rich on this....
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
That's very cool, I'd not heard of offset printing before.
It's a shame your family had to sell their business, as from what you mention it sounds like not all of the printing method changed.
I was wondering with the kitchen method, how you'd get a photo onto the foil, but as you mention a laser could be used. One thing I was slightly confused about, is, is it always necessary to use a coating on the aluminium for that approach.
I guess you could also coat the foil with the photosensitive emulsion you use for PCBs too, and then etch that.
Yeah, I guess I omitted that step as I'm not entirely sure how the actual lithography was performed. I remember a large "camera" where the negative would go into the top and the sheet would lie underneath. It looked vaguely like the reverse of an old acetate overhead projector.
How the image was etched in that process I simply don't remember, but I do remember the sheet going through a number of chemical baths and washings (and being reminded to stay clear of the chemicals as a child).
So there may have been some phase where the sheet was treated with a photosensitive chemical before going into the camera, I simply don't remember the detail.
This link [1] seems to have some details.
It looks like the plates run for a little over $1/plate for the smaller ones. [2]
1 - http://www.offsetprintingtechnology.com/sub-categories/offse...
2 - https://www.valleylitho.com/acatalog/Valley_Litho_Supply_Pla...
Guessing it was something like an Agfa photostat camera. We had one of those at my first job. We used it both for making camera-ready art for ads (we were a tiny business) or positive film to send off to the PCB house to get boards made.
IIRC, the film was standard Kodak 8.5x11 size negatives and the processing was pretty simple. I would do everything from initial tape & wax puppets to the final artwork. Not what I expected to be doing in my first engineering job, but it was fun.
I took a printmaking class sometime later. I think the litho "stone" is made photosensitive and etched, but that aspect of the process is fuzzy. Most of the class was about positive prints and I spent most of my time doing intaglio and lino block printing.
Yeah, that looks basically like the device!
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?
dissolving the soap, cleaning the unetched segments so ink can adhere to them
Ah cheers, makes sense.
Aluminography.
It can't be lithography sensu strictu if you're not using stone.
Literally the definition of lithography [1]:
[1] https://en.wiktionary.org/wiki/lithography