What is the reverse mode?

What we usually call a photo negative, that is, a negative developed from ordinary film, is called a negative. The color of the negative is the reverse color of the image we actually shot. To take photos, we need to re-expose. Only by enlarging it or enlarging it into a photo can it become an image with the same color as the scene we took.

The so-called reverse film, also known as positive film and slide show, is similar to ordinary negative film in use (exposure is better than exposure), and the color presented by reverse film on the negative film is the actual color, which can be used directly, such as showing slides.

It is called a reverse film because the film is negative at the beginning of development and becomes positive when it is developed again after being exposed halfway. So development is also different from negative film. E-6 process is used for reverse film, and C-4 1 process is used for negative film. Brightness and clarity are much better than negative films, and the colors are excellent.

Black film and color film, whether negative film, positive film or reverse film, are divided into black and white film and color film. Color reversal film is used for landscape shooting. Through the reverse development process, the positive image consistent with the brightness and color of the scene can be directly obtained, which can be directly used for projection and printing plate making. The characteristics are: the contrast is greater than the negative film and less than the positive film; The tolerance is smaller than the negative film and larger than the positive film; The minimum density is small, and the substrate is colorless and transparent.

Reverse film (i.e. positive film) is the general name of photographic film used for developing photos, slides and film copies. It can print the negative film on the negative film into a positive film, so that the brightness or color of the image is the same as that of the subject. The sensitivity of black-and-white positive film is limited to purple-blue light, and the sensitivity of color positive film is weaker than that of color negative film, so positive film is rarely used in photography. Color positive is used to print color projection copies (movies, slides). Features: large contrast, low haze, high definition and low sensitivity.

Reverse films can be divided into color and black and white. The current reversal film is actually a color reversal film, which is often used in still life photography. It makes sense to call it a reversal film: the first stage develops to form a negative image, and then uses color dyes to form a positive image. Reverse film is a kind of photosensitive film which can directly obtain positive image after reverse development. Black-and-white reversal film can directly obtain the transparent film of the dark image consistent with the main body; The color reversal film can directly obtain the transparent film with the same color as the subject, and the color is true and bright, but the tolerance is small. Reverse film is widely used in printing plate making or making slides because of its high-quality positive effect. Professional photographers mostly use color reversal films when taking advertising photos.

The reverse film can be played directly by the slide projector, but it is actually no trouble to develop it into a photo. All digital print shops can enlarge. For magazines, the best exposure is normal, because underexposure may lose dark details, thus affecting the printing effect.

Negative influence of reverse plate

Negative film development of reversal film is to shoot with reversal film and develop the film with C-4 1 to turn the original reversal film into negative film. Of course, this is what you have to do when you develop the film yourself. If there is a reversal film, you can take it outside and develop it. Of course, we don't need to use PS. )

The photos obtained by negative film reversal are bright in color and contrast, and the red, blue and Huang San colors of the scenery are particularly exaggerated; Objectively speaking, the negative effect of reverse film is more expressive in color than negative film, and the exaggerated expression of its tone is not as good as that of color negative film, but in hierarchical expression, the negative effect of reverse film is not as good as negative film, so it is very important to determine the shooting subject first and then choose the film type. Reverse negative bias is mainly suitable for portrait photography and some landscape photos. Under the negative influence of the reverse film, the two shooting themes are strongly contrasted, the main body is prominent and the color is bright, which makes the photos have unique charm.

However, it is difficult and demanding to shoot, enlarge and enlarge the reverse film. Therefore, it is particularly important to choose the reversal film properly when shooting. When the light source is sufficient and the contrast of the scene is strong, you can choose a low-sensitivity reversal film to shoot. 50 and 100 reversal films can get saturated and gorgeous photos. In poor light conditions, you can choose a reversal film of about 200 or 400 to shoot. The reversal film with higher sensitivity can reduce the contrast to a certain extent and make the photo slightly softer.

It is the most difficult to control the exposure and correct the color when enlarging the reverse film. At present, there are not many photographers and photographers who use the negative process of reverse film to develop and enlarge, and many color enlarging shops are not familiar with it, so they generally refuse to develop and enlarge. Most enlargers who accept enlarged printing have no experience with reversed negative films, and it is normal that the enlarged photos are yellow, blue and green. It's best for general photographers to clearly point out their own needs, supervise the operation of magnifiers on the spot, and select their satisfactory works through "optimization method".

It is also very difficult to enlarge the negative of the reversal film, because its exposure latitude is best controlled within 0.3 seconds, which is different from the primary colors of this negative film and negative film.

The negative influence of reversal film has a good performance in the application of landscape photography, and its advantage in portrait shooting is also very prominent, but the color reproduction of characters is not easy to be normal, and the faces of characters are prone to yellowing. However, due to the high transparency and contrast, the edge colors of the characters' hair, eyebrows, eyes and lip lines penetrate each other, which is similar to the edge immersion left by China painters on Xuan paper, and has a very exaggerated artistic effect.