نظرة عامة عن قوة التحديد فى الأفلام والألواح الحساسة المختلفة.كتاب أسس التصوير الضوئي

An overview of the strength of determination of different sensitive films and plates

There are no unified, agreed-upon absolute measures to measure the strength of determination in different sensitive films and plates, except for the method of measurement and at the lines per millimeter as we mentioned, and since measuring the strength of determination based on the counting of lines is actually subject to many factors as we mentioned, such as the type of lens, and the type of projector. And the duration of exposure and exposure to light....etc. Therefore, measuring the power of determination on this basis is considered a relative measurement only and not an absolute measurement. This proportional measurement is useful in simply giving a general idea of ​​the ratio between the strength of determination in different sensitive films and plates if they are all measured under one condition, whether with regard to the lens that was used, exposure to light, or display. As an example, we mention the following numbers to indicate the strength of determination in a group of films that were measured Under one condition, all produced by one factory, Agfa. We took it from Dr Edwin Mutter in his book Die Grundlagen der Photographie.

The previous figures are considered ideal, and they have been estimated for the purpose of taking into account. All the perfect instructions that lead to high fixing power.

In addition, the numbers indicating the strength of determination are high in the plates that have been sensitized by the Wet Collodion Process, which is a method that leads to very low sensitivity with very fine grains and is suitable for photo-mechanical transfer processes. The determination strength in wet collodion plates may reach about 180 lines per millimeter, and the plates called Lippmann Plates have a determination strength that exceeds the last number and may reach 300 lines per millimeter. It is used in spectral imaging to record spectral lines in the ultraviolet region
Goldberg was able to prepare a sensitive layer of silver chloride with - collodion with a determination strength ranging around 1000 lines per millimeter and used to photograph and reduce documents