How to remake old photos?

In photography, it is often necessary to remake some photos, pictures and documents. When remaking, we must pay attention to the following four points:

1, the original surface is parallel to the negative surface;

2. The camera lens points to the center of the manuscript;

3. The original equipment and remake equipment must be stable;

4. On the surface of the manuscript, the light must be uniform.

If each part of the original is uneven, it should be covered with flat colorless glass to make it flat before remake; However, when capping the original, the light cannot be reflected into the lens through the glass, otherwise the remake will not be clear.

When using lighting, observe and recreate the lighting position of a plane object. It should be stipulated that the direction of light irradiation forms an angle of 45 degrees with the lens; The intensity of light used on both sides should be the same, and the distance from the object should be the same. This kind of processing can not only avoid the reflection of light into the lens, but also make the picture get uniform illumination.

When shooting outdoors or in exhibitions, we may feel inconvenient due to the limitations of conditions, so we should make full use of natural conditions at this time. When remaking with black and white film, according to experience, "I'm not afraid of light, but I'm afraid of uneven light." In the case of dim light, as long as people's eyes can distinguish the dark shadow lines on the picture; Fix the remake camera on a tripod and expose it for a long time with a medium-speed photosensitive film, and it can be solved. It is difficult to retake in the case of uneven light, and it can only be solved by auxiliary light. If the area of the object is too large, it is difficult to treat the surface light evenly, so we have to find a way to move the object to a place with uniform light and take a new shot.

The correct exposure of the remake is very important to ensure the quality of the remake film. Insufficient exposure, the level of the shadow part of the manuscript can not be displayed on the negative; Over-exposure, the lines on the screen are smudged or mixed with the background, which increases the density of the negative film and makes the silver particles rough and lose layers. When measuring the exposure with an exposure meter, the light values in the brightest and darkest parts of the manuscript are generally used to measure. White paper can be used instead of the manuscript, and the measured light values can be adjusted back two levels as the basic sensitivity.

When remaking small items, if the camera uses a standard lens, a collar or leather cavity can be added between the lens and the camera. Pay special attention to the calculation of exposure when using leather cavity. The reason is that the aperture value changes because the skin cavity is elongated and the distance between the lens and the substrate increases. At this time, the exposure can be calculated by the following formula:

(leather cavity elongation/lens focal length)? = exposure multiple that should be increased.

For example, the focal length of the original lens is 135 mm, and the skin cavity elongation is 270 mm The exposure multiple that should be increased is:

(270/ 135)? =(2)? =4 (times)

For example, the basic exposure time measured by the exposure meter is 1 sec, which is increased to 4, and the correct exposure time is 1*4=4 seconds.

In addition, when remake, the change of light source distance has a very important influence on exposure. When the distance of the light source is doubled, the illumination will be four times different. For example, in the same shooting situation, when the light source is 0.5 meters away from the original, the exposure time is 1 second; If the distance between the light source and the original is changed to 1 m, the exposure time will take 4 seconds.