Who said that we are living in the information society, while information tends to be more fragile than toys ? Can you base a society upon something that will be completely destroyed if you drop it in water, lose it in the wood or simply by a shower of rain ? For millions of years, man has known how to use fire - still we can't prevent it from destroying any knowledge we have put on paper. But - we do have the knowledge of making information permanently durable.

Introduction - about dureadable.info

What is a duragram?



How long will it last?

Why not simply carve it into granite?

Granite blocks are found after thousands of millions of years - of course they must be durable?

Isn't the archive paper durable enough?

HD-Rosetta - a supplement?

Permalect - people can understand your language after thousands of years!

Permaxent - use the inside, fill the interspace and let the back get worn!

Why not send it to the moon?



Look at a scanned image of Permatext in a durable document,
magnified about 5 times as with a pocket lens (877 kB)

Please mail your questions and comments to "f" at "svensk.info". I don't write the sign @ here, in order to avoid a lot of junkmail that would make it hard for me to find your valuable message. Please overlook if I don't reply immediately.


What's dureadable.info?

dureadable.info is intended to be a global portal for everything about durable  information. That's big words, but let's get started. Methods, materials and principles are to be treated in order to make it possible to read your information after thousands of years. But - WHY you would want someone to read it after thousands of years is NOT the subject for this site, that's a more philosophic question - like "Why do people bother about history?" or "Why can't we wait until it's too late?"...

Who am I ?

I am Fredrik Flink, 'a man who lived in the northern Europe during the twentieth century'.

My great grandfather with the same name was a stonemasonry entrepreneur. He maintained a quarry at the island where I now live. I have found it somewhat remarkable that he selected the small area with diorite while the whole region is built up of the far more resistent quartzite. But don't blame him for a sort of mistake that almost everyone commits - to think that "stone is durable". He at least had a reason for selecting the greyish black diorite - he produced gravestones...

What am I not ?

I'm not a businessman, not a scientist, not an author and I have no academic degree. And I am not as crazy as they think...

What is "Swedish Information Foundation"?

It's a small foundation (Informed Stiftelsen Svensk Informationsförmedling) for freedom of speech and for preservation and distribution of information, in which I have been involved for several years sucessfully searching and testing methods and materials for Permadokument - 'dureadable' information.


What is a duragram?

A telegram is something written coming from far away. A dia gram is a graphic representation, in contrast to a symbolic representation by letters and digits. But what do you call something written or drawn which is permanently durable and thus can be left to its own while other messages and objects will be broken down and disappear? As far as I know, there has been no word for that. Therefore, I introduce the term duragram .

A special case of a duragram is a Permadokument (there are some other things called permadoc or permadocument). It complies with certain extreme requirements for permanence and can get through tens of thousands of years out in nature. Finally, there is something called a Permagram. It is a Permadokument that is independent not only of care and time but also of languages, thanks to pictures and figures telling the whole story.

HD-Rosetta is an illustrative example of a duragram that is not a Permadokument. Even grave stones and plaquettes are duragrams, as they are meant to retain the information for a long time even if nobody cares about them. You may call any media a duragram, if you think it will remain by itself.



If you write, as usual, by putting something onto something, three things have to be durable; what you put on, what you put it on and what makes them hold together.

If you write, the other way, by removing something from something, only one thing has to be durable; what you remove from, as the empty space is both formed and fixed by that. And they don't influence each other. Furthermore, as the background usually is a bigger part of the surface than the removed surface, it will take a longer time to erode than if you have put something (ever so resistant and ever so firmly stuck) onto something.

Remove it!

There are at least three ways to remove parts of a surface. You can let acids etc. etch it, but it is difficult to get a clear and deep mark in very small types. Besides, the more corrosion resistant material you have suceeded to find, the stronger acid you need, which is a sort of contradiction.

You can make an impress by pressing a type so that material is moved downwards and to the sides, as the material usually is not too elastic. But it must neither be too hard, which also is a sort of contradiction, as hardness means resistance not only to impress but usually also to scratching, abrasion and erosion. Still, this is a simple method in a small scale and achieves especially very good photographs permanented.

Finally, you can simply 'excavate' the material by carving or scribing. That takes a lot of time, even for a mecanic engraving machine, it is not easy to get very small types and the material still must not be too hard. A laser engraving machine works incredibly fast and not too much slower in hard materials. But a laser can possibly impair the corrosion resistance of an alloy or induce tensions in ceramics. You have to take care of the exhausts as the laser beam converts the removed material into gas and dust.

It's necessary

Man has engraved and imprinted for thousands of years, were all these comments necessary to explain why? Yes, as it is often questioned if engraving or impressing is necessary. For instance, you can use a relatively simple carbondioxide laser to make a mark on top of a metallic surface, while a hundred thousand dollar Yttrium-Aluminium-Garnet laser makes a deep engraving even in metallic materials (still, a carbon dioxide laser seems to be better to engrave ceramic materials, of which some are even more chemically resistant than the best metal alloys).

This is an Yttrium-Aluminium-Garnet laser equipment engraving into - not marking onto the surface of - a plate of Permarit.



My knowledge of durable materials is based on four types of sources: I have tested and rejected a lot of materials that often are supposed to be durable, brass, the very best bronzes, pure nickel, stainless like 304 and 316, copper and aluminium. Others I have been able to compare on the basis of data from manufacturers. Please let me know if you know about any new material and I will test and compare!

It has been very difficult to have experts to state anything about permanence of materials. Maybe it's the nature of the matter. But two things they have actually told me:

It's even more difficult to find data or experiences about corrosion in soil, which is most relevant as most likely information media sooner or later will end up in the ground. It's not like having an acid bath which is the usual case for which data are available. I have carried out a sort of simple, probably not purely scientific, 'test' just to supplement laboratory data. I have extracted a test solution from topsoil, sandy soil, clay soil, ashes and seawater(0,65% salt) which I have concentrated about ten times by boiling it down. Later I have extracted clods from the concentration layer in the ground. In order to simulate long-term conditions by accelerating the corrosion, I raised the temperature to 70-80 degress C by placing the plastic containers(one for each specimen) in an oven. Nothing happened during the first test session over a couple of months, except that the plate of 316 suffered from pitting and general corrosion.

Therefore I installed air pumps (of the type designed for domestic aquariums) with hoses emerging under each specimen and then things began to happen. Now I could measure with repeated results how much even some of the best materials corroded. By weighing before and after very carefully with a mg-balance, I could calculate and compare the corrosion rates between different materials. I think most of the corroding effect relates to the salt water, but mineral particles will cause erosion. Some materials were more obviously not durable, for instance after only 4 days I could actually see straight through the 1 mm thick sheet of 'acid-proof' 316 - and there had not been any acid, just soil and seawater!

The hoses made it happen - by simulating the eroding and oxygenizing effect of runnning water - with suspended loam.

During several years working for Swedish Information Foundation I have selected the following materials as "permanent". The names used here are trade marks registered by the foundation in order to guarantee the right material.

PERMAPITTM - corrosion, abrasion and heat at the same time

This superalloy is especially designed to combine excellent corrosion resistance with very good resistance to abrasion and erosion. Wet abrasion resistance is in the same class as tool steel - but corrosion resistance is in the same class as the best nickel bases. Besides, it's comparable to pure high-temperature alloys up to 1000 degress C regarding oxidation, sulfidation, strength and especially abrasion. Even if ceramics are even more resistant to abrasion, they are not this resistant to impact and thermal shock. Permapit is the new name for this cobalt base alloyed with much chromium and a little nickel, molybdenum, tungsten (half as much as the amount considered to cause tungsten compounds, which can be the case for alloy C-276), iron, manganese and silicon.

PERMARIT® - exclusive and cost efficient

The most resistant of all materials which can be called steel - iron alloyed with chromium, nickel, molybdenum, manganese, nitrogen, copper and silicon. Impressive resistance to corrosion, especially in sea water, and also to abrasion. Usually tens of times more resistant to corrosion than so-called acid-proof stainless (316), except for concentrated sulphuric acid and concentrated phosphoric acid which hardly is found in nature, and a couple of times better than the second most resistant steel. Permarit is often considered equivalent to the well-known superalloy C-276. This exclusive material is the cheapest that can be recommended as permanent. Enough expensive not to be thrown away - but hardly that precious that someone may be tempted to remelt it for profit. It is advisable to choose Permarit if you are short of money, not to limit the amount of text etc to afford a more expensive material - if you still can afford the more expensive, you surely can afford an extra copy in Permarit.

PERMAMIT® - outstanding corrosion resistance

The most recent of super-alloys - I was there at the first delivery to Sweden - yet more versatile than the best of the earlier. The absolutely most corrosion resistant construction material at temperatures up to some hundred degrees C (gold is much too soft and furthermore precious enough to get remelted if it would go astray). Permamit is the new name for this nickel base alloyed with small amounts of copper and iron and, for the first time in history, large amounts of both chromium and molybdenum without any sacrifice in metallurgical stability. Besides, there are practically no tungsten which might break down to tungsten compounds at high temperatures. Supplementary comparisons by accelerated corrosion in natural environment imply that Permamit is some ten times better than Permarit, even after being exposed to fire. Alloy 22, the predecessor of Permamit, is to be used for the American nuclear waste deposition where it is expected to remain for 50 000 years, even if the surface then would have been corroded. Permamit resists even better the manufacturers fundamental tests except for concentrated hydrochloric acid which hardly exists in nature.

PERMATIT® - inert and resistant to natural environments

Titanium is known to be light, strong, oxidation resistant and biologically inert. But most of its alloys has limited resistance to reducing environments or temperatures over 350 degrees C and nickel or chromium may cause allergic reactions. Permatit only contains a small amount of the precious metal palladium, which is enough to get much better corrosion resistance (even in many oxidizing environments) than any other grade of titanium, as well as heat resistance to about 600 degress C. In 3 % hydrochloric acid for instance, it's twenty times better than the nickel base alloy C-276 although this is especially designed for such reducing environments. Titanium may catch fire if you machine it without cooling enough and if that happens you need dry salt, dry sand or an extinguisher of type D, you can't use water or common 'dry chemical', not even nitrogen or carbondioxide. Nevertheless, titanium is very fire-resistant, even at very high temperatures! My own supplementary comparisons implies that Permatit is even more resistant than Permamit in natural, eroding environments, especially after both specimens have been exposed to fire. Even Permatit will be used for the American nuclear waste deposition. The other 'Perma-it' alloys are to a great extent relying on chromium oxide and for the unlikely event that this after thousands of years would show to be less resistant, you could supplement with a copy of Permatit which instead relies on titanium oxide.

PERMAKITTM - not just any table of stone

A cheaper alternative to Permaprit is the only natural material that is permanent - relies on chrystal silicium dioxide (quartz) with a certain degree of purity and crack-proofness. The great difference to the hardly resistant granite is that it requires no feldspar which decomposes so that the quartz grains turns into sand. Permakit survives between ten and hundred times as long as the most resistant feldspar which is comparable to Permarit and which survives about ten times as long as the most occuring feldspar - these two together are about two thirds of granite.

PERMAPRITTM - not just any sapphire

This ceramic material combines extreme corrosion resistance, heat resistance superior to the alloys and most of all abrasion and galling resistance even better than quartz - it can't be worn at all in the ground. Particularly resistant in natural environments as it can't be oxidized at all. But the thermal shock resistance is poor, it can crack in some pieces if the temperature suddenly decreases more than 200 degrees C. Consists of aluminium and oxygen.
Permarit is a tough material. How do you illustrate such a thing if not with this three meter broad plate-shear machine - it could barely manage to cut a 90 millimeter wide and 2,3 millimeter thick plate of Permarit. Note the hoist mounted above. There was a similar result when drilling two 5 mm screw-holes - it took 90 minutes. And I totally demolished two pieces of saw-blades - made by Sandvik especially for stainless and hard materials - by sawing 20 millimeters...



How long will it last?

This is the most difficult question - and maybe the least important. The important thing is to select a material that, according to available knowledge, has the qualification to last longer than other materials. It is not a scientific point that one shall be able to state that this material is likely to last for ten thousand years, but that no one shall be able to state that it is unlikely. The following table shows how many nanometer you can expect will corrode away every year in a common natural environment. It is a guide-line for comparisons between different materials, in no way a guarantee.

Permaprit 0,01
quartz 0,02 - 0,04
Permatit 0,1
Permapit 0,1
Permamit 0,1
Permarit 1
potassium feldspar 1
biotite 3
sodium feldspar 6
oligoclase 10
'acid-proof' stainless steel 10
anortite 4 000 - 10 000
'simple iron' 100 000

If you are going to carve a text into a stone, you should consider this list in durability order:

quartzite, sandstone - weathers most slowly
red gniess / granite
grey gneiss / granite
diorite, diabas, basalt and others
limestone - weathers most rapidly


Why not simply carve it into granite?

For two reasons; first: Granite is actually not durable, as the grains of the really durable quartz are hold together by grains of feldspar, which wheathers hundreds or thousands of times as fast as quartz! Of course granite is durable enough to build a house where it doesn't matter if some millimeter falls off during some hundred years, but that's not what we are talking about here.

Second: I actually asked a mason how much it costs to carve texts into granite. He wanted 7 dollars - per character ! Of course he carves much deeper than a laser engraver - that may compensate for the better material - but I can't pay more than 0.002 dollar per character ! It's not a matter of saving money. The strategic question is: How much shall we let the future know? In Sweden we have runic stones that tell us that "NN raised this stone. His son died during war." and that's the whole story. Will tombstones and monuments be the only messages that we leave behind? Or will the full story be preserved by copying existing documents instead of selecting some short phrases?

Here I actually try to laser-engrave into the gravestone diorite - with a mediocre result.


Blocks of granite are found after thousands of millions of years - of course they must be durable?

Sorry, wrong again. What you find of granite is not at all the surface, but the core of the original rock. If that would be enough you could use a very big piece of anything, simple iron for instance, and it would be a little bit left after millions of years. Bear in mind that the original rock surface of the granite was situated typically ten thousand meters over the present ground level - so much has gone away in a thousand million years ! It is not only stones you find in the ground, there is also gravel, sand and soil - that's what's left of all the rock surface !


Isn't the archive paper durable enough?

Maybe for thousand years - IF you keep it in a safe archive, with the right temperature, the right humidity and with no flooding, no fire, no desperados and no despots - for thousand years, just think of our history until now. If you don't, someone of some of ten generations could just throw it away, out in the bush. Even if they don't simply burn it up, it won't remain for many months. That resistant is archive paper!


HD-Rosetta - a supplement?

A very interesting concept, which a few years ago suddenly occured to the public (in Sweden through a popular science program on television) is called HD-Rosetta. A ion-beam engraves microscopical characters onto a nickel plate.

The great advantage over Permadokument should be the economy, as I had understood it; by making text and figures so small, you shorten the manufacturing time and less material is required. However, it's not easy to get a clear picture, but it seems that the cost for HD-Rosetta is of the same order as for Permadokument, some dollar for a thousand characters.

I can see three draw-backs with HD-Rosetta vs Permadokument, first: The small characters are also very shallow, the engraving depth is only about 60 nm while the Permatext in a Permadokument is about 10 000 nm, and I suppose HD-Rosetta was never intended to be 'left out in the bush' but cared for in an archive. If the nature's forces are allowed to work, the text in HD-Rosetta would be worn or corroded away in about 99 % shorter time than the Permatext, provided that it's engraved into the same sort of material. But that's the second draw-back; HD-Rosetta is made of pure nickel, a far less resistent material than even the cheapest material for Permadokument. So it wouldn't be unreasonable to guess that a Permadokument could survive thousands of times longer than a HD-Rosetta. The practical consequence should be that you can never leave a HD-Rosetta unattended. But you can maybe afford to save more information.

The third drawback is the size of the characters and figures. Of course, it's a major advantage that it can be read with just an optical microscope instead of temporarily available digital equipment. But can you be absolutely sure that the technological development will not turn into a retrogression so that in a distant future there wouldn't exist any microscopes? Because in that incredible case you would have no possibility to read the HD-Rosetta. A more likely problem might be that someone who finds the nickel plates doesn't discover the text and just leaves it - but HD-Rosetta has an intelligent solution where the text are beginning with large characters, getting smaller and smaller, so that the reader can understand that it continues with microscopical characters. A Permadokument is not only superiorly durable - it's always ocularly readable, for most young persons without any aid at all and if you have a poor eyesight you can just use a simple pocket lens.

HD-Rosetta and Permadokument are not necessarily competitors, but could supplement each other. You could think of a scale where 'all' information is available (hopefully for some years) in digital media, maybe half of it on paper(for some decades), some percent in HD-Rosetta(for some centurys) and the most important, still not just some short phrases as on the stones but maybe one per mille, is saved in Permadokument for thousands or maybe millions of years - if HD-Rosetta still is much cheaper. The more important, the less amount selected and the more durable.

Of course, HD-Rosetta and Permadokument have determining common advantages over all usual media: The information is analogue, readable without any other instruments than possibly optical lenses and there are no paper burning or moulding or ripped.


Permalect - people can understand your language after thousands of years!

I am going to make a permanent picture dictionary in order to once and for all document both that languages which have the best chance to survive - English and Interlingua - and some languages which are locally important and on the long term run the risk of dying out - Swedish, South Lappish and Swahili.

I calculated the cost for carving such a dictionary into stone. Seven dollars per character, according to the mason. Each entry consists of five letters on an average and is explained in at least five different languages. Then four thousand entrys would cost almost a million dollars - and even if I might get some discount, the four thousand pictures are not included...

For less than a tenth of that cost, I can laser-engrave the dictionary into Permaprit, a material that dissolves 99.9 % less rapid than a typical feldspar, the main constituent in granite. Furthermore, it's considerably harder than quartz, which means that it will never get worn out by common soils, wind or water. Despite that the text carved into stone would be larger and deeper, my dictionary will last longer and even get a chance to survive a few ice ages - of course it is impossible to state, but a million years is not unlikely.

Fig 1. The modern - and improved - Rosetta stone: A test edition of Permalect, laser engraved in Permarit four years ago. The simple principle, which is intended to be logically intelligible even in a very different culture in a distant future, is that the contents in each of the identical halves of the frame should be equivalent and that each line represents one language (in this case english, interlingua and swedish). In order to save work when drawing and costs when engraving thousands of entries, the pictures are very simple - no masterpieces...


Permaxent - use the inside, fill the interspace and let the back get worn!

Permaxent is the ideal combination of a Permadokument and a time capsule. It's not a compromise - both the document and the capsule get even safer! The really durable plates protect both the contents and its own engraved insides.

If there is any foible in a Permadokument made of Permarit, it would be the fact that any material can be scratched and worn by anything harder or just as hard - for instance running water with grains of sand for thousands of years. No engraving can get any depth. Permaxent turns the document so that the wear and corrosion primarily hits the back. The outside can be worn more than a millimeter instead of the inside beeing illegible when worn a hundredth of a millimeter!

The capsule is designed not to damage the contents while closing by welding or opening by sawing. Time capsules are containers for objects which are to be preserved for the future. Usually made of steel, copper or lead, yes, even plastic, they are not very durable and often intended to be opened after only fifty years. Even if the contents wouldn't be fresh after more than some hundred years, Permaxent is designed to live much longer than that. It's all-welded from a 2.3 mm thick plate of Permarit.

The first model manufactured is intended primarily for colour prints - one of few sorts of information that yet can't be put into a Permadokument. Copied on Fujifilm chrystal archive paper, they are garantueed to remain intact after 60 years 'of normal handling'. It's not easy to get more answer than that, but Fujifilm says that it would survive 'considerably longer' stored in a dark, dry and airtight container like Permaxent - especially if air is replaced with argon, which is my intention. Maybe it makes not much difference, if the prints fill up the whole rectangular box, and maybe it's better to leave some humid air as the prints can bulge if the environment is too dry.

Fig. 2 Not just a time capsule - but a superior time capsule combined with a superior document.

An inert atmosphere?

But to preserve other objects of irregular form, argon is very useful. Until recently, no compounds with argon at all were known. It has now been shown possible for argon to react under certain extreme conditions which simply can't occur in the box. The lighter inert gases neon and helium are still regarded as absolutely non-reactive, but they may be more difficult to fill into the container as they are lighter than air. The heavier inert gases krypton and xenon are expensive and not better than argon. Furthermore, it's a good principle not to put strange substances into the capsule, as one might in a distant future discover that they are, however inert, not healthy. Argon is frequent in every breath we take, and even if you let out buckets of argon in a room, it wouldn't exceed by more than some tenth the natural content.


Why not send it to the moon?

Of course it could be a good idea, if you've got the money, to place an extra copy on the moon surface where it's not exposed to air, water, wind or rain erosion, nuclear explosions or other human whims. But it wouldn't be wise to send the only copy to the moon, because:
To be continued...    Published 2005-02-28  Updated 2009-10-09  Copyright Fredrik Flink 2005-2009