Understanding the composition of medical films

Before discussing the composition of medical films, let's first introduce what medical films are. As the name suggests, medical films are used for medical purposes. Common medical films can be categorized by printing method into laser films, thermal films, and inkjet films.

While understanding the types of medical films is common, many medical professionals are unaware of their composition. They typically only recognize the specifications and types of medical films, but not their components. Therefore, this article will provide a basic overview of the composition of medical films!

First, let's look at the composition of traditional medical films. They are usually composed of four layers: the photosensitive emulsion base layer, the film base, the protective layer, and the bottom layer. The bottom layer also has another name: the bonding layer.

Next, let's look at color medical film. This type of film is composed of multiple layers, mainly including: a protective layer, an upper photosensitive emulsion, a filter layer, a separator, middle and lower photosensitive emulsions, a bonding layer, a film base, and an anti-halo/static layer. The photosensitive emulsion is the core component of the film, and it is synthesized from gelatin, silver halide, and other additives, so its internal structure is quite complex. Because of the special nature of photosensitive emulsion materials, a detailed explanation is needed here: When it comes to gelatin, you might not expect that this material is actually extracted from animal bones and skin—amazing, right? Through various high-tech methods, a high-grade animal glue is extracted and then processed into gelatin.

Next is silver salt, which is a salt compound formed by metallic silver and chlorine, bromine, and iodine, chemically known as halogens. This might be unfamiliar to many, but simply put, chlorine + bromine + iodine = salt compound – it's a chemical reaction. Finally, there are other additives, generally chemical agents called additives. Adding these additives, combined with gelatin silver salt, creates a photosensitive emulsion.