صيانة التصوير واختباره ٢_a , من كتاب تكنولوجيا التصوير , د.م محمد حماد

The rest of the painting is to show the restored or re-photographed place... Also, the tempera colors ensure that the work looks like the old work without exaggerating its elegance.

Scientific examination of the images:

All treatment of the injury in the imaging panels, and every analysis of the test that is conducted... must be based on scientific methods and methods of research... It supports and guarantees the expert diagnosis of the injury so that it can be treated. However, it is wrong to believe that it achieves an objective guarantee in terms of complete technical knowledge of the work of art, since it is a means of critical understanding and not its goal.

Natural means:

It can be summarized in the following points:

1- Good lighting: It is one of the primary conditions for each examination...whether it is natural or artificial light, it is necessary to determine the direction of the light rays in a way that shows all the features of the painting. For this, three types of traditional lighting can be used: ordinary rays, which are perpendicular to the surface, oblique rays, which fall at an angle of 540, and tangential rays, which fall at a very small angle of 000. In practice, electricity can be used to distribute the excitement.

And for good vision with the eye... Different magnifying devices can be used to make the examination more accurate, whether with a lens, a microscope, or a single lamp with capacitors or color filters. The small microscope with internal illumination allows a close look at the structure of the image formation. It also allows. binakoscope. The possibility of analyzing small objects on the surface as a result of extreme magnification, and it also allows photographing them with the Mono Leitz Pinacoscope.

Photography: Each note must be recorded according to the aforementioned methods... Each step of the work is followed by a photographic image that can be referred to to make the necessary comparison and record the different stages.

Photographic magnification is particularly useful for determining the method of drawing according to a subject

Photography or color paste and its degrees connection, transition to shadows, and identification

Cracking properties.

As for the delicate details of importance, related to the composition of the canvas, cracks and dyes... microphotography is used (photos taken with small angle lighting are always preferred... because this lighting lies in clarifying the similar touches of the brush...
Polaroid In order to avoid the effects of dazzling light (blurring) arising from bright light... polarizing lenses are placed in the middle, but this method has the disadvantage of partial determination of the light intensity, which harms the clarity of the vision atmosphere

It even shows the photographer's personal fingerprints, which helps to identify the artist's own work and confirms it conclusively.

- Special methods of examination.. It is possible to raise the level of the parametric examination, preferably the quality and capacity of the circle or beam of light used, and the use of the rays used, which we will mention later:

(a) X-rays (X-rays) X-ray vision and photography under it are now the base in the study of all laboratory observations, and the principle of each of them is the difference in the absorption of rays by bodies depending on their molecular weight - and also that the shades of color with a smaller partial weight disappear with respect to those that It has a heavier molecular weight, and accordingly, an evaluation of the antidotes can be developed in relation to the material, and data for detecting things that are not visible in the image, and for certain color combinations, and on the fluorescent barrier, the different values ​​of the color spots are valuable clues in clarifying the lower layers of the colors of the image... and such That silver white and vermilion (vermilion red) are colors that are clear curtains for vision. Likewise, we find the metallic color formed on the basis of lead carbonate, which appears black when examined by x-ray.

It has been observed that the colors change with time, and this follows the importance of using aspidage in the preparations and in the base used in the lining to prepare the cloth and color mixtures.

Thus, it was possible to discover the first case of the drawing whose author was not known... For example, two opposite pictures of Tinos could be distinguished by the photographer Rembrandt, and by radiographic examination it was also possible to discover the layers of pictures that were drawn on top of each other.

(b) Ultraviolet rays: We find that the ultraviolet rays that fall on a drawing that has been previously cleaned or restored ... allows distinguishing the color tones that are intended to be created, or distinguishes between the realistic or real state of the photograph and the re-drawing or restoration layer, no matter how accurate it is. ...thereby creating a kind of evaluation order

The rule in ultraviolet radiation lies in the property of certain materials that have a fluorescent effect (i.e. absorb light and re-radiate it) by the effect of radiation resulting from a barrier, Wood, and the property that has this effect varies in function according to the composition of the used materials such as dyes or adhesives. It is also possible to obtain The contrasting effects are much clearer than using the naked eye, for example, two colors
It appears that they are identical, but in reality they are chemically different, and therefore they do not have the same effect under ultraviolet radiation. Also, the light-generating phenomenon that accompanies receiving ultraviolet radiation for some objects that are examined... varies according to their age. Hence, a practical measure can be determined as a result of known experiences.

Preferably, ultraviolet rays can also attack impurities that may be in cracks, dead ends, filming over the original image color layer, fungus and mold factors, fingerprints, as well as signatures and writings that are not visible in ordinary light ... and all of these things appear clear and specific Exactly if it uses ultraviolet rays in its research.

(C) Infrared: It is also possible to raise the level of photographic reconciliation thanks to infrared imaging by means of special barriers. This method has given impressive results in the evaluation of dark-colored materials. This method sometimes replaces the search methods by ultraviolet rays

(d) Other methods: In addition to the aforementioned methods, the sodium lamp method was finally used. If its lighting completely changes the nature of color vision... it allows easily to see imaging above the original image and incidents that are difficult to see with the naked eye, and here an infrared filter and barrier is added, and this method is excellent for laboratory analysis

réfractomètre As for the methods of physical and chemical analysis, they are multiple, and the most used is the spectrographie method and the deviation scale. The first helps to check the colored materials, and the second can, with the help of the deviation table, facilitate the study of adhesive materials. The method of fading the colors of the dyes is also possible with the photocolorimeter, and the spectrophotometer, which allows the identification of the colored substance by its light absorption curve. It is a method that can be supplemented by fluorescent radiation spectroscopy - the special spectral curve of the light that a dye transmits when ultraviolet radiation falls on it.

At the present time, spectral drawing can preferably conduct a chemical analysis of the entire part of the material used in any artwork.

Chemical means of examination:

It is one of the most important means for researching works of art and can be summed up in points

next .

1- Sampling: It is necessary for examination to know the nature and composition of the layers of drawing and the chemical components of the colors. Samples are taken by means of a hypodermic (thin) syringe needle that is published and retracted, by pressing its tooth in an inconspicuous corner.