All high temperature fired porcelain dinner sets with traditional underglaze decoration, which means Blue Fluted Plain, Blue Fluted Mega; Christmas Plates among others are suitable for dishwasher. Even very old inherited dinner sets can go into the dishwasher.
Onglaze decorations such as Flora Danica and similar dinner sets are not suitable for dishwasher. Very efficient detergents might after some time remove the decoration. We recommend hand wash and to follow the specific product information.
Our bone china dinner Starfluted can go into the dishwasher, but the decoration will wear of over time, therefore we recommend hand wash. In general, one can say, that if there are gold, silver or other metals in the decoration, we recommend hand wash, since the decoration will wear of over time by using dishwasher. It is recommended to follow the product specific information. Gold decorations at the rim - and other places - is typically present as a layer of gold/ metal on top of the glaze. Therefore it is very vulnerable to mechanical wear. This means, that e.g. cutlery can wear of the gold decoration. A scouring sponge might likewise wear of the gold/metal layer. We therefore recommend using the soft side of the sponge or a brush.
All types of porcelain with metal decoration (gold, platinum, silver etc.) cannot go into the microwave. It is recommended to follow the product specific information.
Regular oven and fan-assisted oven
All types of porcelain are oven proof and can in general go into a regular oven. Oven proof means that you need to heat up slowly and cool down carefully again. Porcelain cannot be put into a preheated oven – or be taken out and put on a cold table. The temperature difference can get too big, and the porcelain can break.
Fan-assisted ovens can give big local temperature differences and the porcelain might break. It is not the temperature in itself that is critical. It is the high temperature differences that will give thermal tensions in the porcelain under heating and cooling.
Porcelain of all types can go into the freezer. When defrosting, do not warm up too quickly. The temperature difference can get so big, that the porcelain may crack and break.
Cutlery marks and scratches
It is normal that a plate gets marks of usage. Cutlery marks and small scratches can appear even the first time the plate is used. The marks can to some extent be removed with Vienna polishing chalk, which can be bought in department stores. It is important to follow the instructions for use carefully.
We have for many years experimented with cutlery, and there is a big difference in how cutlery leave marks on the porcelain. Some cutlery leave a lot of marks and some are hard to remove again. If the marks are severe then, with some luck, polishing material for glass ceramic cooking plates, can be used for cleansing. Scratches are looked upon as normal wear and cannot be removed.
No glaze on the edge of cups
When glost firing the porcelain, it is necessary to remove the glaze from the place, where the porcelain is supported when placed in the kiln. Thin porcelain cups are typically fired upside down, which means, that their contact with the support in the kiln will be the cup edge, and therefore the glaze has to be removed. If this is not done, the items will get stuck to the kiln support. The support for cups is a special item, which at the same time helps to keep the cup circular during the firing process, where e.g. the weight of the handle could deform the soft porcelain at the high temperature. After firing, the unglazed edge of the cup is polished completely smooth.
It is possible, that tea and coffee after some time can be deposited on this polished edge – and this is normal. The resulting discoloration can be removed with scouring powder or soaking in some diluted chlorine solution. In the "old days" the advice was to scrub the edge with some coarse salt. Usually, though, normal dishwashing should be sufficient to keep the edge clean.
Appearance of the blue colour
The high firing temperature for the porcelain makes the blue colour react with glaze and body. This reaction is a part of the final appearance of the porcelain. It means that e.g. the straight lines in the Blue Fluted pattern will flow with the glaze and the underlying structure. Colour and glaze will typically run away from "ridges" down in the "valleys" in the fluted pattern. A former straight line will be wavy/ irregular and appear light in colour on the "ridges". This is especially visible on Blue Fluted mega, where decorations and reactions are magnified. On a coherent, blue surface on e.g. Blue mega or Blue flower, it is also normal to have "white lines", that reflects the underlying reliefs. Generally, you can say, that the high temperature reactions contributes to the final appearance of the porcelain in line with hand crafting, which is always visible in the products.
Shape irregularities - warping
The high firing temperature strongly influences the final shape of the porcelain. The total shrinkage is after glost firing 12 - 15%. You can say that the porcelain has got a kind of "memory" due to the use of plastic materials like clay and kaolin. These materials are responsible for this, and they also affect the shaping process itself. Handling and structure might not be seen before firing, but they will highly contribute to the final appearance of the product. It is not possible to produce hand crafted porcelain without having irregularities and warping in the final product. Usually, it is not very visible because the warping and ovality will be insignificant and in fact contributes to the normal, attractive look of high fired porcelain. There are defined limits for acceptable irregularities, and these are a part of our normal quality control.
Appearance of the porcelain over the years
Royal Copenhagen started the production in 1775. Many changes have happened during the years. The factory has moved several times. Different machinery and kilns have been utilized over the years, and the number of employees has varied between 200 and 2000.
Every change has had some influence on the appearance of the porcelain. Raw materials, e.g. can affect the whiteness and size. The kilns affect the colours and the glaze. The decorations, which are often handmade, are very much influenced by the employees and the general style that is predominant at a given time, where painters and instructors were able to influence the looks of the products. The changes that appear through altering production methods cannot be avoided or helped. Dishes and cups produced after 1950’s can be thicker than before – it is simply not possible to produce the thin items, that earlier were made manually. New and more efficient kilns give more uniform products, as we can observe today.
We have through decades and centuries by quality standards and education strived to maintain a high and uniform quality. It will be possible to observe differences between products made today, 50 years ago and 100 years ago. Quality is - in many ways – a subjective and difficult matter to handle and differences are not possible to avoid. We are striving, that our products give the same expression as 100 years ago.
Mending of broken porcelain
Is it possible to mend broken porcelain? It is frustrating to break one's porcelain. Generally, we say that it is not possible to repair broken porcelain. In "the old days” there were shops, where you could have your porcelain mended. Royal Copenhagen does not refer to such shops, and we have no possibility to make any repairs.
Christmas plates can be used as normal dishes
People frequently contact us because they are worried if they can use Christmas Plates to eat from. The Christmas Plates are originally produced as a decorative object for collectors. But it has also been the intention, that they could be used as normal dishes. In japan, e.g., it is quite normal to use the Christmas Plates for eating purposes. The materials - body, glaze and colour - that are used for producing Christmas Plates are precisely the same as those that are used for producing the normal dinnerware, e.g. Blue Fluted Plain, Blue Fluted Mega, etc. We have through the years complied to - and still do - the authorities demand for food contact materials. Especially underglaze decorated items like Christmas Plates, Blue Fluted, etc. are completely resistant towards all external materials influences - that is dishwashing, food contact etc. Danish Veterinary and Food Administration regularly visit Royal Copenhagen for control.
The resulting report can be seen under "Smiley"
Faience is fired the first time at approximately 1160 - 1200°C, which gives the faience its final shape and strength. Second firing, the glaze fire, is approximately 100°C lower than the first fire, and typically the items are placed in special racks. The faience body is porous and a little water-absorbing. After some time in use, the faience might develop crazing in the glaze layer. By absorbsion of water in the porous body, the body expands a little and the glaze layer cracks. This is a normal faience phenomenon, and the cracks will develop unrelated to the way, the faience have been treated – meaning that dishwashing, hot or cold storage, humidity, use, etc., has no special influence on the development of cracks. The daily utility will not be affected by crazing, and the faience will not lose its strength. The combination of a porous body and a not totally tight glaze layer can mean some periodical discoloration under the glaze. The areas, where the faience has been hanging during the glazefire, will typically leave some unglazed areas, where some humidity can penetrate and make discolorations. If it is water, that is absorbed, the discoloration will disappear again. If it is some kind of grease, a more permanent discoloration can be the result. Typically, this might happen with a butter jar. The faience glaze is lead containing, and this was originally necessary due to the low second firing temperature. The lead glaze gives the faience its special look and materiality. The lead itself is a part of a practically insoluble compound, which is used in the glaze. When the faience was produced, the raw glaze was tested for lead solubility (because of the employees) and the fired product was tested as well (because of the consumers). We have all the years complied with the requirements of the authorities. It is perfectly safe to use as well new as old faience to eat from every day. Throughout the years, the best know faience dinnerware has been Blue Line, Tranquebar, Ursula, For All Seasons, and many others.
Thermal mugs – occurrence of cracks and leaks
A thermal mug consists of two shells with air in between. The cup appears to be thick, robust and heavy. But in reality the shells are a bit thinner than what to expect, and the cup in general is more vulnerable than one would think. The mugs are not weaker than other porcelain cups. They can be used on a frequent daily basis. Breakage is mostly caused by a hard stroke, since they often, because of their appearance, are expected to have better durability than other thinner cups.
If a thermal mug is leaking, meaning if fluids come from the cavity between the shells, it can be caused by cracks in the shells. It can also be caused by a defected closing of a small hole in the bottom of the mug. The hole is made for technical reasons, and it is closed with sanitary silicone, before the mug can be taken into use. If the silicone over time should be worn out, it is very easy to repair.
If a leak occurs because of the hole in the bottom, then the cup can be placed on a radiator overnight, bottom down. The fluid will then run out of the hole or vaporize. The hole needs to be completely clean and dry, before it can be repaired with sanitary silicone again.
Flora Danica – colours and decoration
The decoration on Flora Danica is a so called onglaze decoration, which means that the decoration is painted on top of the already glost fired porcelain plate and afterwards fired at approx. 870 °C. This technique and firing temperature is used to get the, for Flora Danica, special materiality and colour richness.
Colours for the Flora Danica decoration traditionally contain lead; it has been so since production started in 1795. The lead content is necessary, because this makes it possible to give the decoration its special and unique look. Even if we have been working for years on getting the lead out of these colours, we have not yet succeeded to find a mixture that can replace the lead in the colours and at the same time keep the unique materiality and colour richness.
The finished product in Flora Danica is produced under the legislation of Denmark and EU in regards to lead content in such kind of products. The colours become insoluble, and the legislation is in compliance, which means it is not more dangerous to eat from Flora Danica than from any ordinary porcelain item.
It happens that some of the raw materials, which are a part of the Flora Danica colours, no longer can be purchased. A great work is put into finding substitution raw materials that will give the exact same expression as the missing colour. The variations which occur in Flora Danica through the years will only be because of the handcrafted items and the many different painters that have painted the decorations.