Application of Densitometer in X-Film Industry

Time:2019/12/10 15:54:00 Browse:520

Some time ago, a hospital customer asked if there is an instrument of Linshang that can measure the X-film optical density value. Our sales staff recommended the Linshang LS117 densitometer to the customer. Since we don't know about the X film industry, we only recommend this product as we know that Linshang LS117 densitometer can measure optical density values. Later, we made a detailed understanding of X film. The specific situation is as follows.

1. Why the LS117 densitometer is not suitable for yellow film

The X film used in hospital is mainly divided into two types, black film and yellow film. Linshang LS117 densitometer can measure black film but not yellow film. Yellow film refers to the coating of a transparent polyester sheet with an extremely thin layer of azo organic matter. It is a photosensitive tool made by ultraviolet light exposure and a photolytic plate that is decomposed by light. In the process of reproduction, the original master film can be transformed into the next-generation daughter film with the same photosensitive polarity, which is also called diazo film or brown film in the industry. Therefore, what yellow film needs to test is the optical density in the ultraviolet band. Because of the internal structure of the LS117 densitometer, it is not suitable for testing ultraviolet light sources, so it is impossible to test the optical density value of yellow film.

2.  Test the black film with LS117 densitometer


Black film is also called silver salt film, which is mainly used to reproduce work films, but work films are not necessarily only brown films. There are also black films for work films. The biggest difference between a black film and a brown film is that the brown film needs ultraviolet light exposure and the black film needs to penetrate white light. Therefore, the optical density value is also measured in the white light range of 380nm-760nm. Linshang LS117 densitometer adopt the light source from 380nm-760nm, so it can be directly used to measure the optical density value of black film. So when you buy our products, you need to confirm whether you are using yellow film or black film. If it is yellow film, we do not recommend you to buy our products.

3.  Linshang LS117 densitometer

The Linshang LS117 densitometer is made using the principle of diffuse projection, which can measure not only the transmittance value of the material but also its optical density value. The optical density value is actually the performance of the material's light-shielding ability. The optical density value is a logarithmic value and there is no dimension unit. Optical density is the logarithm of the ratio of incident light to transmitted light or the inverse of light transmittance. The calculation formula is OD = log10 (incident light / transmitted light) or OD = log10 (1 / light transmittance).
      The Linshang LS117 densitometer is suitable for measuring the following materials:

  1. Matte, opalescent, translucent materials and other materials with diffuse transmission principles.

  2. Absolute optical density values of aluminized film, black film, mirror ink, etc.

  3. Measurement of absolute optical density value, relative optical density value and dot area ratio of black film.

  4. The LS117 densitometer can also measure transparent and highly reflective materials, but a black flannel needs to be added for testing

4. Densitometer standard

JJG920-1996 "Verification Regulations of Diffuse Transmission Visual Density Meter"

JJG178-2007 "Verification Regulations for Ultraviolet, Visible and Near-Infrared Spectrophotometers"
The light source of the Linshang LS117 densitometer conforms to the CIE photopic luminosity function and can pass the inspection of Chinese national metrological certification. A powerful guarantee for your light transmittance and optical density value measurements.



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