I'm making a tattooed repository of paramedical knowledge for a religious ceremony. How small can words be if they're tattoos made of cremation ashes?

Question

I have a character. One of their parents died. Said parent was cremated, and then - by their own choice; this is a quasi-religious thing - their cremains were mixed into tattoo ink, and the character was tattooed with that ink.

The character in question is a paramedic for a religious order, as was their parent before them; before said parent's death, they both agreed that said cremain tattoos would be in the form of writing - specifically writing on various types of first aid, as a memory aid - not for simple stuff like CPR, stuff like "here's how you identify and treat a sucking chest wound", or "here's how you insert a stent".

With modern tattoo technology, how small can words written with cremain ink be? This is relevant, since the character in question is trying to pack as much information into as little of a space as possible.

Answer 1

QR Code

In a modern setting, one could tattoo a QR code with a link. This link could direct the user to a web-based medical text.

This prevents your information from going out of date as medical knowledge changes, and you could set up the webpage / phone to read the procedure upon scanning.

You could include QR code links to several common procedures, as well as the equivalent of the manual's homepage. The tattoo for the homepage lets you manually navigate to whatever information you need, meaning the information density is effectively infinite.

Size

You can make QR codes pretty small, but I'd probably keep them ~2x2 inches to ensure that the code remains readable even after it fades, or for when you have to read it in poor lighting, weird angles, etc.

Answer 2

Tattoos will fade and blur over time, though just how quickly depends on many factors. Some examples here.

Tattooists are generally reluctant to do small text, because it can become illegible and/or ugly pretty quickly. For instance, one tattooist in this discussion says "Unless its very basic single width lettering like handwriting, we wouldn't do anything smaller than about 15mm high" (roughly 42-point font).

You might be able to go a little smaller if you're willing to settle for "ugly but readable if I squint". But even at 20-point, the amount of text you could usefully tattoo is probably no more than what could be memorised with a few hours study. And if your paramedics are planning to work with modern protective clothing and gloves, or in dirty conditions, there's no guarantee that any tattoo will be usefully visible. It's hard to see this being a good alternative to just putting in the time to learn what they need to know.

Note that IRL, medical advice changes quite frequently. For instance, the international CPR guidelines are revised every five years; a tattoo with that kind of info would very quickly go out of date. Depending on your setting this may or may not be an issue.

Rather than using tattoos as a practical reference in emergency situations, it might make more sense to pick something symbolic, if there's room for that in your story. That escapes the need for the tattoo to be visible and it makes information density much less important.

Answer 3

I would suggest drawing and iconography instead of writing. Essentially if you have ever seen the series Prison Break, one of the main characters have the blueprints to a prison drawn into a full body tattoo.

in your case It could be a tracing of all the bones, major blood vessels, nerves etc. for example white for bones, red for blood vessels, and blue for nerves.

You can then add iconography to explain different procedures, so need to set a dislocated shoulder, a series of arrows for pull, twist and a line from the arm to the torso so you know where to align the arm before you release.

Need to do a cesarean, you have a dotted line where the cut is supposed to be.

It should be possible to derive a lot more information from this, than having a direct text that would often be hard to read as it's on some part of your body that is hard to reach.

Answer 4

You could make the words small by using shorthand.

https://en.wikipedia.org/wiki/Shorthand

Although the primary use of shorthand has been to record oral dictation or discourse, some systems are used for compact expression. For example, healthcare professionals might use shorthand notes in medical charts and correspondence.

There are lots of different shorthand systems. A lot of shorthand systems are phonetic. Here is a translator for Gregg shorthand.
https://steno.tu-clausthal.de/Gregg.php

I put in the first paragraph from your OP and got this: