The importance of conservation and restoration of historical objects has caused the role of function, the meanings of words and their use to be surveyed in such a way as to preserve the concept of its cultural validity. This validity of words will arise in practical communication and their concepts, although appreciating will not be possible without understanding and inferring them. Also, it seems necessary to analyze the meanings and the clarity of difference and similarity of the words used for the lost areas of the painting. Objective: The aim of this research is to check the concepts of the words "lack" and "defect" in the field of conservation and restoration until their correct use is specified and also to find the appropriate word for the missing areas of paintings or lacuna. Research Method: This essay is based on a descriptive-analytical and comparative research method. It collects information from the research of predecessors, benefiting from sources related to theoretical reviews in connection with the restoration and reintegration of the lost areas of painting, and uses encyclopedias of different languages. It deals with the approaches presented by the thinkers and evaluates the special concepts of lack and defect in restoration discourse. Findings and Conclusion: In this research, it seems that lacuna in the science of Conservation and restoration means an empty space and a missing part. The word "lack" also refers to the missing part, while the "defect" part is the absence of a part from the very beginning. On the other hand, the words lacuna and lack in Latin, equivalent to Lack and Loss, indicate the missing part, although the word deficiency is equivalent to Defect. The discussion and results acknowledge that the missing areas of the painting is the same as lack, in other words, it was there from the beginning and is not present now. While the word defect represents the absent areas of the painting that were not there from the beginning and are not there now. Therefore, it seems that the word lack is a suitable equivalent for the missing part and the word lacuna..

The Qajar-era Qalamkar cloths belonging to the Golestan Palace had been folded in wooden boxes in the warehouses for a long time. In alignment with the objective of preventing physical and biological damage to the fabrics, the process of organizing and restoring them was investigated. This was accomplished through library studies and the performance of necessary analyses, which will be explained quantitatively throughout the article. The
activities carried out to achieve the goals of the mentioned project are as follows: after photographing and documenting the fabrics, a technical and restoration certificate was prepared, and labels made from cotton fabric were sewn onto the cloth. Additionally, cleaning and dusting were performed, and the process of smoothing the folds was conducted to prevent deformation and physical damage at the fold points. Subsequently, the pH level was checked using pH meter strips. Fungal cultivation was carried out on Qalamkar works suspected of having fungi, and fungi cultivation was also performed in both the former and new storage areas. A fiber identification test was conducted to determine the type of fiber present. The results of the analyses indicate that the pH of the fabrics is within the neutral range. The fungal culture analysis revealed that Aspergillus niger grew on one of the fabrics and the door of a wooden box used for storage. Due to the presence of this type of fungus, periodic monitoring was recommended. The fiber identification analysis also confirmed that the fabric is made of cotton cellulose fiber. Finally, the Qalamkar fabrics were covered with cotton fabric and secured. Identification tags
were attached to the works, and with sufficient care and precision, they were transferred to the standard reservoir of Golestan Palace. Furthermore, protection and restoration solutions were provided to maintain the fabrics in the best possible condition.