The Role of Color in the Decoration of Tiling in Islamic Buildings of Seljuk Era

Islamic art has specific importance in different sections especially in the area of architecture and the related decorations. Generally, decoration has an important role in the history of Iran’s architecture and it has been continuing from far past to today and has preserved its continuity. In Seljuk era, Iranian artists decorated exterior parts of building with fine parts of turquoise glazed brick. In this way, we observe color in exterior decoration of buildings in this era. This method of decoration is used from old times and new techniques and diversities have been utilized by passing time and the architectures have constructed the most beautiful and enduring buildings.


Introduction
Iran has been the heritage of many valuable artworks from the beginning until now; the artworks that represent the interest, thought and skill of creators.Indeed, many of these artworks have secrets and their creators have made them to reach a spiritual goal.Investigations show that color has great role and influence on human's behavior and we must to go into the world of colors with a good eye to have the new horizons.When we are inserted to this wonderful world, we observe that color has effective connection with human's behavior and his/her life; from soothing colors to the colors that create turmoil.Human is interested to color and coloring according the importance and influence of color in its life and in the other hand according the extent and frequency of architectural decorations.By the establishment of Seljuk government, Iran entered to a new stage; especially in the area of architecture and the related decoration, the artists of this period by the protection and encouragement of central government succeeded to invent new designs.They created a beauty and coordinated combination by making glazed bricks and its application in the decoration of building surface.This method which was formed by the enthusiasm and invention of artists became an introduction for fabrication and acme of mosaic in Iran's tiling.The samples of buildings in Seljuk era which were made by tile decorations are: the minaret of Damghan Mosque, the tomb of Khajeh Atabak in Kerman, and the Red Dome in Maragheh.

Minaret of Damghan Mosque
Damghan Mosque is located in northeast of Damghan that belongs to Seljuk era.This mosque includes a vast ambit, bedchamber, three porches and one old minaret.The ambit of the mosque has the dimensions of 38*36m2 and the south side has three porches which the middle porch is larger.Two bedchambers are located on both sides of porch and the height of mosque's minaret is 26.75m.The lower section of minaret is flat and decorated with thin bricks and this minaret is actually among the first buildings that are decorated by single-color tiles.Turquoise tiles are located among the parts of brick in minaret view and these turquoise glazed bricks as quadrilateral parts have surrounded all over the minaret.

Tomb of Khajeh Atabak in Kerman
This tomb is constructed in 530 (Hijri).The building has octagonal plan from inside and outside, and also it has a dome that is related to one of Kerman's Atabaks named "Khajeh Atabak" the famous minister of Seljuk kings.This octagonal tomb is built on a high-altitude brick platform.Its internal and external surface has different decorations with the materials of brick, plaster and tile in different forms.The entrance of this building is located in southwest corner.Around entrance and octagonal of building is decorated by circular column-like using patterned bricks and by pointing method.Each of these sides has brick-work with designs of plant, star and variant regular and irregular polygons.Passing the entrance, we enter an octagonal space; in west side, a frame with rectangular design is located and a combination of bricks with geometrical designs as netting is filled in this frame.
There can be seen no blank space in this building.The altar has a rectangle shaped frame and an arcade which is firmed on two columns with two square-like column-head.Turquoise tile has been used as fine parts for filling the spaces between the patterns of brick and molding, and plant and Eslimi patterns are used for filling the background of inscription.The roof of building includes a short brick dome which is decorated inside by brick designs.This tomb is the first building in which parts of tile are used for decoration.

The Red Dome of Maragheh
Maragheh in East Azerbaijan has an old history and is one of the historic and old cities of Azerbaijan in Iran.This building has a quadrant plan from inside and outside of this entrance from north; the decorations of this building include brickwork, plastering and tiling (glazed brick).There is a brick column in the four corners of this building which is decorated by turquoise tile parts amidst bricks.Each of the four sides of this building has two high arcades which are arcuate in the top.Above these arcades, there is a small window in the middle for supplying the light to internal space.The artist has made decorative patterns with full skill of by brick and by troughs and prominence which create penumbra.The entrance of the building locates inside an arcuate arcade which its top is constructed by bricks as inscription with Kufic along with ornamental geometric patterns in the north side.Also, beautiful designs are created around inscription by glazed brick and unglazed brick with overlapping polygons.
In the gable of this arcade, turquoise glazed brick parts can be observed and in the context of decoration for this building, the layout of glazed and unglazed brick parts is indeed the continuation of brick decoration in the buildings including Samanid tomb and/or Kharaghan towers.Inside building is a quadrant plan and is covered by a coat of plaster.Evolution of tiling technique is shown in gable of entrance head and the background of entrance head triangle is filled by a rigorous design of band-shape decoration.

The Blue Dome of Maragheh
The Blue Dome is a tower-like building that is located in the center of Maragheh city and has decagon plan from outside and inside.There is no valid information on the date of construction and the buried person with regard to the collapsed inscription above the entrance which is the only part that has remained letters and dates to 593 (Hijri).
The building has decagon plan and the internal top section is as two underneath floors having crypt design and the top floor is also decagon.Plinth of the building is completely made by stone and the other sections are made of brick.All sides of external building façade are divided into two parts except the entrance side.
The first part after stony plinth is decorated completely by brick parts and different geometric designs.The second part which continues in a few rows to the roof is in the form of arcuate arcade.Inside each arcade, three rows of smaller arcades exist and after them, the first row of inscription and the next row have muqarnas decoration.
A context was prepared for artist to create and invent without any limitations by creating stability and calmness in society especially in economy.One of these works is the change in architecture decoration.In the late Seljuk era, in order to pull out the building surface from single-color state and uniformity of brick, the artist decided to change the background of decoration among the color to give beauty and freshness to the surface of building.On the other hand, according the philosophy of Islam and the culture of society, the artist was forced to begin the work cautiously.Indeed, the selected color must have no restriction in terms of access to glaze, dyeing oxide and the method of fabricating glazed brick.Finally, among the colors, turquoise color which is obtained from the combination of copper oxide and alkaline glaze and its application returns to before Islam is selected.Indeed, the artist having enough experience in the context of glazed brick fabrication and achieving turquoise color along with brick performed a work that didn't expect a good future for it, but this action obtained a great position soon and changed the path of architecture decoration.By making glazed brick and its application in buildings' decoration, Iranian-Islamic architecture entered to a new stage.These glazed bricks were commonly made with turquoise color and having a size equal to unglazed brick.Indeed, the level of work and the type of decoration is the continuation of brick decoration in the buildings like Samanid tomb and Kharqan towers with the difference that parts of blue brick is observed amidst unglazed decoration.These turquoise parts were sometimes located as fine fragments amidst plant and geometric patterns which were created by plaster and brick (one example is the tomb of Khajeh Atabak in Kerman).It has been also used as letters of an inscription (like minaret of general mosque in Damghan).The application of this color in inscription is because writing with an opposite color to background color makes attention from far distance.Another reason is having a heavenly and calmness implication for inscription especially verses of Quran.The factors which were effective in the selection of color by artist, in addition to personal interest of the artist were world view and society religious, literature role, view of Islamic philosophers and access to metal mines.With regard to the selected buildings in this paper (decoration of minaret tile of Damghan Mosque) the artist has been trying to consider the application of building in the decoration of building.Therefore, with regard to the symbolic role of blue color in building decoration, the artist aimed at to give a sacred state to this building and according the rules of Islam which has orders for all dimensions of human life (spiritual and material), therefore the direct presence of religious in all aspects of life is observed including in the field of selecting colors, and the position of many of the colors can be seen by referring to the verses of Quran and the artist continues its work confidently with regard to the position of blue color in Islam.

Conclusion
Beauty is the instrument for catching perfection, provided that we have received the meaning of beauty and not to allow being without understanding of fact by beauty.Human have been facing with the magical effects of color since he entered to this world.He regulated himself with a world of colors in collision with the most beautiful arts unconsciously.Dark blue has been known as calmness, sunrise and golden yellow as activity and attempt.Therefore, mankind has been always dealing with color.One of the reactions of mankind against nature is using color to decorate its living place in the continuation of using color in decorating buildings from one cultural period to another period by growth, and technique of brick-work and plastering finally leads to coloring in tiling which continued from the simplest tile to the most complex tiles of Islamic period.The artist indeed follows a logical relation between sensible and meaningful forms of reality by selecting color.On the other hand, the artist by inspiring from natural colors and by considering nature and world as a sign and code knows it as a sign of god's existence; so follows discovering this code.Therefore, this artist selects special colors in a space that has spiritual and emotional state that eyes sees the changes by looking from one surface to another.This selection of colors by artist is not merely because of aesthetic, but the artist addresses the expression of feeling and inner perception.With regard to the method of used materials and colors in the intended periods and the evolutions that occurred after in this area and led to beauty decorations, therefore it is necessary to provide the convenience by identifying architectural decoration especially in the field of tiling art and selection of color by architectures and also in the evolution of this art based on need, current technology and facilities in order to gain new experiences with modern materials and method until we can use valuable artworks in this field of Islamic architecture decoration and by selecting spiritual and mystical colors.

Figure 3 .
Figure 3.The Red Dome of Maragheh

Figure 4 .
Figure 4.The Blue Dome of Maragheh