What is permanent and what is not
In world-famous museums such as the Louvre, British Museum and the Metropolitan Museum of Art, you can see artifacts of ancient civilizations in places such as Egypt, China and Greece.

Among such ancient fine arts and crafts, what remains today are stone sculptures, ceramics and china, and objects made of metals such as bronze and gold. Most clay tablets from ancient civilizations have been broken, and the fragments that have survived until today are mostly small pieces. There are few wood objects remaining. It is believed that Sima Qian’s Records of the Grand Historian, a very important Chinese work, was written on bamboo slips, but the original has not been discovered. What we have today is a copy made in later period.

And then there is paper. It is said that papyrus was widely used in the ancient Mediterranean world, but apart from Egypt where the climate is dry, there is little ancient papyrus that remains today. The oldest papyrus in existence is a blank papyrus scroll, found in a box in the tomb of Hemaka, a high official of Den, the pharaoh of the first Egyptian Dynasty. It is thought to date to around 2900 BC. Apart from in Egypt, the oldest papyrus found dates to around 750 BC, written in Hebrew, and was excavated from Murabba’at, a cave near the Dead Sea.

Source: Papyrus (Egyptian Bookshelf), by Richard Parkinson (Author) and Stephen Quirke (Author), University of Texas Press, 1995.

In China, paper was invented in the Han Dynasty era, but old papers were lost to mold and rot, or were burned in repeated warfare and natural disasters, and not much remains. A piece of paper excavated in Gansu province is believed as the world’s oldest. It shows a map from the pre-Han era, and its estimated to date from 150 BC.

In this way, whereas artifacts made of stones, metals and porcelain can be seen at almost any museum, there are few examples of ancient paper that have been preserved to this day, and; therefore, opportunities to see them are limited. Paper is fragile and fleeting.

The life-span of color photographs

Whether it is a traditional analog photograph or an output from an ink-jet printer, a color photograph is said to last for about 100 years. This means that, if a photograph is kept in an ideal condition – in other words, in a dark place away from gases that cause discoloration – it is anticipated that it will keep 70% of its original color after 100 years. This does not mean that there is no discoloration after 100 years. In addition, since it is paper, there will be wrinkles and folding marks, and if the humidity is high, it will go moldy and smudge. It is almost impossible to completely block the impact from noxious fumes and ultraviolet rays. Color photographs may last up to 100 years, but in practice, 40 to 50 years is more realistic.

Black-and-white photography

Let’s move onto general black-and-white photos.

Traditional analog black-and-white photographs called gelatin silver prints and images are produced using silver, and are believed to be more durable than color photographs using dyes and organic pigments.

Amongst gelatin silver prints, photographs printed on traditional printing paper, called baryta printing paper, are carefully treated so that no chemical remains, and are often used in cases where long-term preservation is required. Durability is believed to be enhanced if the colors in such photographs are then adjusted using selenium, gold and other agents.

Further, photographs printed using platinum or palladium instead of silver can last longer, and some believe that they will last for 300 years if stored in good conditions.

However, they are nonetheless mere gradation information adhered to paper. If continuously exposed to light, any paper will be altered and will discolor, and can be easily damaged with little force.

How about using base materials other than paper?

One theory holds that black-and-white photographs produced with photographic technique called daguerreotype, which prints images on silver-plated copper plates, can be preserved for a long time. They are, however, very easily damaged, sensitive to open air, and very easily deteriorate unless kept under strictly controlled conditions.

Movie films such as Kodak’s VISION3 Digital Separation Film 2237 and Fuji Film’s ETERNA-RDS separate color films into three colors and expose each of them digitally onto three monochromatic films, mimicking the old Technicolor method using a dye transfer process. Konica provided such service in the mid-1990s. Some say that these archived films will last for several hundred years, but they are either ESTAR Base or polyester-base (PET). They can be stored over long periods of time only in strictly controlled environments, and are just as easily damaged as other films. In terms of the durability of images themselves, since only simple silver images can be obtained from normal process using designated MQ-type monochrome developing fluids such as D-96 and D-97 and acid-fixing solution, their durability is lower than that of prints toned with selenium. In other words, they are about as durable as common microfilm.

The advantages of conventional microfilms have been rediscovered in recent years. The resolution of microfilms optically exposed to light is remarkable, and even surpasses that of regular photographic lenses. Nothing compares to it in terms of combined overall information density capacity and durability. That said, it is still PET-based, and has similar limitations to that of movie-archiving films.

The website of Fuji Micro Corporation states the following:


Silver halide photographs have a history of over 100 years, and have also been used as microfilms for over 80 years.

In 1992, the conditions for the long-term storage of microfilm was established by International Organization for Standardization, namely ISO 5466, and ISO 10602, which define the expected life-span of microfilm to be 500 years. Microfilm is the only information storage medium whose long-term storage stability is officially recognized. Storage conditions were also established in the Japanese Industrial Standard JIS 6009 in 1994. Storage conditions defined by JIS are 30%-40% humidity and a maximum temperature of 21 degrees Celsius.


All of these films need to be stored in a place kept at a stable temperature and low humidity, with no exposure to ultraviolet rays, and further, should ideally be kept away from gases such as hydrogen sulfide. Unless in a museum or a specialized storage facility, it is almost impossible to store photographs in such conditions.

Moreover, we believe that the value of photos in that they are viewed. We doubt that it is worth putting photographs in deep storage to avoid light.

In addition, what we must not forget when we think about the durability of photographic images is that there is no guarantee that such a store system will be in place several hundred years from now, even in a public archive. You never know what will happen to the nation itself.

Can data last forever?

How about digitized data – can it last forever?

Many music CDs produced in the twentieth century are now not playable due to abrasion of deposited aluminum layers. With formats such as CD-R and DVD, durability has supposedly been improved; however, even with DVD-R discs which are for long-term storage and archiving purposes, the estimated lifespan is a mere 30 years. Furthermore, if the mechanism to play such media ceases to exist, there is no way to retrieve the data, and the only way to store such data is to continuously copy it to other new types of media. This is a primitive method of storing information, just like the oral communication tradition before letters came into existence.

Various recording media which claim to be able to store information over long periods of time have been introduced, but there has been no drive invented for such media which can stand the test of time.

Methods of recording on quartz glass have been proposed, but unless the drive to read such data has a similar level of durability, it is essential to have an easy way to read it without relying on the future technology. However, we have not heard of any examples of this being achieved.

Hard discs crash easily. When they do, their contents disappear without a trace. The life-span of a hard disc is said to be around 10 years, but any given hard disc may break tomorrow. Even with SSDs (Solid State Drives), sectors are destroyed after a certain number of re-writes. The more you use one, the closer it is to the end of its life.

Making back-ups is not a fundamental solution in regard to long-term storage. Even if you use cloud storage, no one knows whether the server will still be managed and maintained 100 years or 200 years from now. Since digital data is mere electrical signals without any physical backing, it may be said that it is less secure than photographic prints, and there is no guarantee that it will survive into the future.

This is why there is still demand for the above-mentioned movie films for archiving, and the lifespan of digital data is fast shorter than that of archive films.

In addition to the number of years for individual data storage, we do not know how long will current binary data formats last. These formats may be replaced totally different ones with higher storage efficiency and convenience in 100 years’ time, and taking into account developments achieved in this area over the last several decades, it is rather unrealistic to assume that this will not happen. Even digital formats may no longer be available in the future. If this happens, digital data which is currently used will no longer be usable.

Digital data is a format for distributing information, and we rather consider it to be fundamentally unsuitable for storing information for a long period of time.

Eternal images

Our products are made of stainless steel and brass.

As its name suggests, stainless steel hardly ever rusts, and Millennium Photos and Stainless Photos, which are made of stainless steel, do not change almost ever when kept indoors in a normal living environment. Even outdoors, they can retain their images for long periods of time unless they are constantly in contact with seawater.

Brass is an alloy of copper and zinc. It is believed that brass has been used since before the 4th century BC, and it is sufficiently tough to be used for coins in Japan. Brass itself rusts when left untreated; however, the rust itself is a strong protective layer, prevents brass from rusting further, and this protective layer allows the brass to stay extremely stable, so that it will almost never change. Patina finishing for Millennium Photo utilizes this feature and makes images emerge by controlling rust.

With brass clear-coat finishing, images are coated with highly durable synthetic resins and can keep their gloss and colors for several decades if kept indoors; however, they are not suitable for very long-term preservation.

With brass bass finishing, colors will dull gradually with time by reacting with water and sulfide gases in the air. This finishing gradually changes into an antique color, such as that seen in Buddha statues: however, it is not suitable for very long-term preservation.

Other companies’ products create images by applying photographic emulsions onto metal or printing pigments on it; however, the lifetime of images created in this way is the same as that of paper photos, with the image just adhered to a metal surface. No matter how strong the base metal is, there is nothing which can be done when the image deteriorates with time or if the image comes off from the base.

About stainless steel

Despite its name, even stainless steel can sometimes rust. You may have seen rust on a kitchen sink made of stainless steel.

When people say “stainless” steel, they actually refer to several types of material.

SUS430 (equivalent to UNS S43000 or SAE430 in the US), which is a type of ferrite stainless steel, referred to as “18/0”, contains only 16-18% chromium, and does not contain nickel. This type is cheap; however, it can rust even with water as you can see in a cheap kitchen sink created by bending thin plates. You cannot expect this type of material to last for 1,000 years.

SUS304 (equivalent to UNS S30400 or SAE304 in the US), which is widely used for cutlery, such as spoons, and building materials, is called “18/8”, and contains 16-18% chromium and approximately 8% nickel. This is a type of austenitic stainless steel, and is totally different from ferrite stainless steel in terms of its crystal structure. SUS304 rusts less than SUS430, and is stronger, with a better gloss and texture.

Marine grade stainless SUS316 (equivalent to UNS S31600 or SAE316 in the US), which is used for Millennium Photos and Stainless Photos, is also austenitic stainless steel, and SUS316 has higher corrosion resistance due to it have approximately 2% molybdenum. It rusts less than SUS304 and has sufficient durability to be used for sea water pumps and sea ships.

A familiar example of the use of SUS316 is in kitchen products. Sauces contain many kinds of ingredients, and since they have stronger corrosive action than you may expect, storage containers made of general SUS304 can corrode after short-term usage. SUS316 is used for this kind of purpose.

Also, there is another type of SUS316 stainless steel, called surgical stainless, and it is used in field of medicine for injection needles and body implants.

SUS316 is expensive and difficult to be process; however, we use it to ensure quality due to these characteristics.

There is an easy way to identify types of stainless steel. SUS430 sticks to magnets in the same way as iron; however, since SUS304 and SUS316 are not magnetic, they usually do not react to magnets. Since SUS304 and SUS430 have different colors, you can identify them once you know them, as long as they are finished in the same way; however, you cannot distinguish between SUS304 and SUS316 by their appearance.

It is said that cheap stainless steel from countries such as China rusts relatively easy since it contains many impurities. Stainless steel with a name such as SUS316 complies with JIS, and SAE316 complies with SAE. The only metal which you can call SUS316 is that which satisfies the standards.

For Millennium Photos and Stainless Photos, we use only high quality Japanese SUS316, which conforms to ISO and JIS standards.

SUS304 is also used for a card type in the form of a business card.

Durability of Millennium Photos

Stainless steel contains chromium, which forms an extremely thin coating a few nanometers thick, which is referred to as a passive layer, and since it functions as a protective layer, stainless steel does not rust easily like iron. Since the passive layer can be quickly restored even if it is destroyed, stainless steel is very stable overall.

Chromium compounds used to cause environmental pollution through industrial waste water. This was caused by hexavalent chromium, and has nothing to do with the chromium which is contained with stainless steel. Grains contain a lot of trivalent chromium, and this chromium is a vital mineral rather than a poisonous material.

Sometimes you can see rainbow colors with the appearance of an oil film on the welded joint parts of stainless steel products such as for construction. Also, there are products with rainbow color patterns on motorbike mufflers made of stainless steel. This coloring is called “temper color”, and is not caused by an oil coating but by the stainless steel itself, and the principle of the rainbow colored appearance is the same for oil coating or soap babbles. This is slightly technical; however, it is called a “structural color”, and although the material itself does not have an actual color, this is a phenomenon in which colors are caused by light wavelengths or other micro-structures. This is equivalent to optical interference due to a thin film. The film itself is completely transparent but light reflected on the film surface interferes with light reflected on the base, and such interference gives rise to the appearance of color by enhancing or offsetting particular wavelengths of light.

Temper color is an oxidized film of iron, which is a component of stainless steel; however, the black coloring of a Millennium Photo or a Stainless Photo is created by further developing the passive layer created by chromium contained in in stainless steel until it is no longer transparent, and such black color is much stronger than temper color. This is a condition in which the passive layer which originally protects stainless steel and makes it rust-resistant is thickened.

Also, if you closely observe a Millennium Photo you will see not only black and white grooves, but also finer grooves in dark parts and fine concave and convex forms in white parts. These grooves and convex/ concave forms cause optical interference, and under strong lights such as direct sunlight you can see fine rainbow color sparkles. This is also a structural color applying the same principle as that in the rainbow colors on CDs and DVDs.

Images on Millennium Photos are formed with grooves on metal plates, and processing creating black color by changing the properties of the positive layer of the stainless steel surface is applied only to engraved convex parts. With this unique technique, the color tone on images is reproduced by adjusting the brightness ratio between dark parts and glossy metal parts. As mentioned above, this black color processing reduces metallic reflection by changing the properties of the stainless steel surface. This color will never peel off, because unlike painting and plating, it does not make color adhere onto the surface. This method is highly corrosion-resistant and light-resistant and will never discolor, unlike paintings. Images created using photographic emulsion ink, and paintings will inevitably wear out and will fade when exposed to light as well as harmful gases in the air, as well as with rain and wind. However, since Millennium Photos and Stainless Photos are made of 100% stainless steel and do not use emulsions or painting in coloring, they technically will never wear out. Therefore, Millennium Photos can maintain important photos for subsequent generations without change. It should be emphasized that Millennium Photos are totally different from photos, which are images drawn on thin and vulnerable film. Millennium Photos are photo metal engravings, which are a new type of media that is neither a photograph nor an engraving.

Do they really last 1,000 years?

Millennium Photo is a registered trademark of Millennium Photo Inc., and it is a product name which symbolizes the fact that this product’s color is essentially permanent. Stainless steel has durability which allows it to last for over 1,000 years when kept indoors. On the other hand, brass products wear out earlier than this. In the case of brass products, it can be expected that they will last for a long period of time as long as they are kept indoors, but they are not suitable for outdoor use. In this way, the product’s condition may vary depending on the environment in which it is used. We do not guarantee that our products will last for 1,000 years.

In Japan, there used to be a photography product manufacturer named Konica, who promoted their full-color photo prints as being “100-year prints”. They were implying that their products would maintain approximately 70% of their color intensity from just after they are developed even after 100 years, as long as they are kept in ideal storage conditions. This actually means that their products will wear out faster in worse conditions. For example, if they were kept outdoors exposed to rain, they would instantly wear out, and if they were allowed to be exposed to direct sunlight, even if kept indoors, they would discolor within several months. Nonetheless, Konica’s full-color printing paper had a reputation of better image durability than the products of other competitors at that time. Thereafter, Konica merged with another company to become Konica Minolta, which was releasing the following announcement until they sold their film/image paper business:


Konica Minolta 100-year prints are high-quality, and were invented by using photo-sensitive material technology developed by Konica Minolta over many years.

In particular, these prints have high color durability, which is an important aspect for photo products, allowing beautiful high-quality photos to be retained indefinitely.*


*Details of methods such as 100-year printing evaluation methods are shown below.

Evaluation methods:

We conducted an accelerated wear test in a dark place on prints processed using our evaluation criteria. We used the Arrhenius law to estimate the storage time. The results suggested that photos can retain their images to a visually acceptable extent over approximately 100 years if they are stored in an appropriate place, such as an ordinary album at an environment at 24°C and 60% humidity. The visually acceptable extent is set based on our imaging monitor evaluation, and the image retention rate is estimated to be 70-75%.


Points to note in storage

Please do not store for long periods of time with direct exposure to sunlight or fluorescent lighting.

Please avoid high temperature and humidity.

If using an album or glue for pasting photographs, please use products suitable for photos.

Note: The above shown number of years was obtained based on a simulation from an accelerated wear test performed by Konica Minolta Photo Imaging, and is not guaranteed.


Source: Konica-Minolta’s “100-year print”


We cannot say that our Millennium Photo images will remain completely unchanged for over 1,000 years. However, we are confident that a Millennium Photo image retained for 1,000 years would undergo less change than a conventional photo stored for 100 years. This is because it is less likely for a Millennium Photo product stored in the above conditions to lose 30% of its image intensity after 1,000 years. If it is accepted that the “100-year print” product name is not an exaggeration of performance, then there should be no problem with the name “Millennium Photo”.

From amongst all products in the Millennium Photo series, stainless steel Millennium Photos and Stainless Photos have the highest durability. These use SUS316, which is a type of stainless steel with particularly high corrosion resistance, and this type of stainless steel almost never rusts when used in normal conditions. This material has sufficient durability for semi-permanent storage. Even if kept outdoors, these products can maintain their original condition over a very long period of time in actual use, as long as they are kept in a normal environment such as one which is not near the coast or an industrial zone. Also, these have the highest hardness amongst products at our company, with HV hardness of approximately 200 (SS400, which is a general structural tensile steel material, has HV of 100 to 125 – please see http://www.kikaika.com/sekkei/zairyou/index.html), and Millennium Photos and Stainless Photos seldom break over long periods of time, even if they are rubbed or hit by other objects, permanently retaining the images on them. We recommend Millennium Photos or Stainless Photos for use on gravestones and outdoor use.

In the indoor environment, there are no factors that would cause these products to wear out unless a strong force is applied, or unless they are exposed to a strong acid in order to intentionally destroy them, or unless they are placed in a high-temperature environment such as being directly exposed to a gas-stove fire.

In short, these products have durability which allows them to last semi-permanently if kept indoors. Even if kept outdoors, we assume that they will sufficiently last several hundred years, even though we have not obtained the results of an accelerated wear tests using outdoor gravestones in inland areas. Fine dot-shaped rust may develop in certain environments such as in coastal areas where the products are continuously exposed to salt.


What is permanent?

A major art gallery in Japan has the following stipulations for their guidelines for managing their collection.

The collector curator may dispose of a work in the collection registered as an asset if any of the following items apply.


(1) Work which cannot be used an educational/ research material due to it not being possible to repair significant damage or dirt

(Items 2 and 3 omitted)

(4) A work considered to not be necessary to be retained

(5) Other work which the collector curator considers acceptable to dispose of


In other words, the above rules stipulate that collections of works are to be disposed of if the art gallery curator considers it to be unnecessary to retain them, or considers it appropriate to dispose of them. Even public art galleries which are committed to retaining art works that are irreplaceable cultural assets of a certain area publicly declare that they will not retain all works in their collections forever, but will select to be retained, as necessary.

The above is only one example; however, it appears to suggest that even art works owned by art galleries, once recognized as valuable, may not be retained forever.

Although it is only a rumor, it has been said that some art galleries in Japan secretly dispose of some works in their collections every year.

Since even libraries are nowadays mercilessly disposing of some books, it may no longer be a good idea to assume that certain items will be retained by somebody forever.

Given the above, who will keep records that we were here in this period of history, to pass on our culture to the next generation?

If we cannot expect this role to be played by public institutions, such as art galleries and museums, individuals such as family members, friends, and children can do this instead. There are a limited number of such people who see this as an important thing to do, and who will keep such evidence and pass it on to the next generation.

This is why we handle our customers’ photos with the greatest possible care. We consider our customers’ photos to be significantly more valuable to each individual customer than a collection of artwork in a gallery. We believe that individuals’ photographs are never less valuable than artworks viewed as valuable by public organizations, and that they should last forever.