Purple: Buildings of National Importance.
These nationally important buildings include important works by architects having a national reputation, buildings or groups of buildings designated as National Historic Landmarks by the National Park Service, or unique examples illustrating American architectural development. In addition to the architectural significance of the buildings in this classification, they may be associated with historical events or persons that have national importance. It is of the utmost importance that these buildings be preserved, be properly maintained, and when needed be carefully restored.
Blue: Buildings of Major Architectural Importance.
Buildings in this classification include outstanding examples of works by notable architects or builders; unique or exceptionally fine examples of a particular style or period when original details remain; buildings which make up an important, intact grouping or row, even when some of the buildings within the group have been defaced; and noteworthy examples of construction techniques when the original fabric of the building is basically intact. All buildings included in this category should be preserved, be protected from unsympathetic modifications, and have original facade treatments properly restored when possible.
Green: Buildings of Architectural or Historical Importance.
This category includes buildings that are typical examples of architectural styles or types found in New Orleans, when the building retains its original architectural details and makes a notable contribution to the over-all character of a particular area of the City. In some cases, buildings of lesser architectural importance will be included in this category if they introduce an important keynote to an area or have specific historical significance related to either an historical event or person. It is important that buildings covered by this classification be preserved and when feasible, restored as closely as possible to their original appearance.
Red: Important Buildings that have been Altered.
This category includes important buildings that have had much of their exterior architectural details removed or covered. Due to their scale and basic construction, however, these buildings still make a notable contribution to the overall character of an area. If a building in this classification were to be properly restored or renovated, the rating would automatically be raised. Though placed in a lower category, the significance of these buildings should not be overlooked or minimized.
Gold: Buildings that Contribute to the Scene.
These buildings generally date from the late nineteenth century or twentieth century and are typical examples of an architectural period or style. Though these buildings are of lesser stylistic importance, and are frequently quite modest in appearance, they are important to the character of the area due to scale, materials, and/or increasing age. If a particular section is to retain its present character, it is important that examples of buildings in this classification be preserved as closely as possible to their original form and character. If the character of an area is to be changed, a selected number of these buildings might be worthy candidates for preservation.
Grey or Black: Unrated Buildings.
Buildings that have not been given a specific architectural rating are generally twentieth century structures that have no real architectural value. Although some of these buildings have a detrimental impact on the area in which they are located, others are sympathetic to adjoining buildings due to their texture, proportions and massing.