Metallographic microscope observation is the basis of metallographic photography. After observing the samples prepared by the metallographer, he finds it necessary to take pictures, and can take pictures of the phase organization by means of a photographic device. The process of metallographic microscope photomicrography includes: selection of photographic objective, eyepiece and color filter, installation of photographic device, adjustment of light source, adjustment of light bar, selection of film, photographic focus, photographic exposure, etc.

Metallographic photography is the recording of objects by means of photographic plates. The more detail and clarity you record the image, the better the quality of the photograph. However, whether the film can record the image well depends mainly on its resolution. In other words, in the metallographic photography of the metallographic microscope, the high resolution of the objective lens alone cannot obtain good metallographic photos, and the negative film also has a high resolution, so as to reflect the high resolution power of the objective lens.

(1) Resolution of photographic plate

The resolution of the film is an indication of the film's ability to record the details of the image. It depends on the size of the silver salt particles on the film. The smaller the silver salt particles, the higher the resolution of the negative, and vice versa.

The resolution of a film is expressed in terms of the maximum number of distinguishable lines per millimeter. Generally photographic plates have a resolution of up to one millimeter. A thin line, that is, can be separated from the orange 25 micron two points pull open. Considering the impact of the bottom film processing technology on the resolution, the low resolution of the negative film can be achieved to distinguish between two object points 30-90 microns apart.

Because the resolution of the film is higher than that of the human eye, that is, the object points that can be resolved by the photographic film can not always be resolved by the human eye, so it is often necessary to enlarge the object images recorded by the film so that they can be seen by the human eye. If you want to make the human eye more comfortable directly from the negative print out of the photograph; To identify the organizational details, the image of the negative can be properly enlarged printing.

To sum up, if the photographic negatives need to be analyzed and studied by enlarging the printing phase, the effective photographic magnification of 12ONA-360NA can meet the requirements of the resolution of the negatives.

Effective magnification micrograph between 120 na - 36 people on, than effective magnification microscopic metallographic microscope inspection, so the special advantage of metallographic photography, because the photography magnification is not high, so the general photography ocular magnification is not large, most of the 10 times in the following, an instrument, equipped with one or two different multiples of the eyepiece of photography, Has been able to meet the requirements of use.

In metallographic microscopy, the use of a higher power eyepiece will not increase the appearance of tissue details, but it will obtain a larger picture. For people who need to view a large number of metallographic pictures, the eyes will not be tired easily. Therefore, on the premise of ensuring the quality of the photo, it is permissible to choose a photography multiple slightly higher than the effective photography magnification.

(2) Measuring the photographic multiple of the instrument

When photographing metallographic pictures, you always want to enlarge them as accurately as possible. But the muddling magnification is not only determined by the product of the magnification estimation of the objective lens and photographic eyepiece, but also affected by the length of the obscura. Therefore, it is necessary for metallographic analysis to accurately measure the true value of photographic magnification. The measurement method is as follows: an objective microscale with an ugly partition lattice value of 0.01 mm is placed on the carrier. Adjust the photomicrograph system to be calibrated and focus so that the image of the micrometer is clearly visible on the ground glass of the camera obscura. Use the caliper to measure the width of the side micro ruler 10 grid image on the ground glass. If the image width of the 10 grids on the micrometer is 40 mm.