Photography techniques for positive and negative processing

In a lighting environment with abundant light sources, or when you want to achieve the effect of strong contrast and perfect portrait texture, you can use medium or low sensitivity positive films to shoot, such as 64-degree and 100-degree positive films. You can get quite saturated and vibrant hues. However, the exposure latitude of a positive film with this sensitivity is extremely narrow. If the light ratio is not carefully controlled, the exposure will fail, resulting in underexposed dark brown or overexposed dead white.

To avoid exposure failure, or if you want to obtain soft contrast in the photo tone, you can use a positive film of around 200

or 400 degrees to shoot. Currently, 200 degrees is used on the market. Slides are the most popular type of film because they have a wide exposure latitude and are easier to shoot with and have softer contrast. It should also be noted that the positive films of some brands will tend to be extremely yellow, or magenta, bright green and other tones after such abnormal processing. Of course, this is also related to the color temperature when taking pictures. All in all, photographers should adjust according to their own preferences to obtain the ideal color tone. ． During post-processing, try to use soft focus printing as little as possible, otherwise it will be easy to form black hair in the black hair part of the portrait's face and penetrate into the white part, which will become an extremely weird phenomenon. This is an inherent phenomenon of soft focus printing during general post-processing, but it is more prominent in positive and negative-process photos.

This effect is actually obtained by mistake, because the operator or user mistakenly develops the positive film as a negative film, so that this effect occurs. Later it became a common method to pursue special effects.

Because the positive film can also become a negative film during development in the negative film process, but the color saturation is very high and the contrast is also very high. The positive film does not have a color mask for correcting the color of the negative film, so the positive film cannot be returned to a normal color photo after enlargement, but its exaggerated and strong colors are a good artistic style. So now many photography enthusiasts deliberately create this effect.

In the field of digital cameras, it is impossible to obtain the positive and negative processing effect in this way, but another tool - PHOTOSHOP, can also achieve this effect. It was first concocted by Taiwanese netizens. Mainly using PHOTOSHOP to adjust the color and contrast to simulate the positive film processing effect of a film camera. Positive films are mostly used for landscape photos with particularly bright colors, a wide variety of colors, or large blocks of colors with clear boundaries.

The effect of the positive film is that the color is particularly bright and the contrast is high, which often creates a strong visual impact on people.

In fact, the secret of this modulation lies in adjusting the color levels of the red, green, and blue channels respectively. After duplicating the original image into a layer, adjust the levels of the three color channels on the new layer. Just adjust the contrast and brightness after you're done. 1. Open a picture. On the channel control panel, select the blue channel, pull down the image menu and use the Apply Image command, select Invert, use Multiply for the blending mode, set the opacity to 50%, and confirm.

2. Select the green channel, repeat the above operation, but set the opacity to 20%, and confirm.

3. Select the red channel, or use the Apply Image command, set the blending mode to Color Burn, leave the other settings unchanged, and confirm.

4. Use the Levels command to adjust the light and dark levels of the changed blue, green, and red channels

Blue---21 0.76 151

Green---46 1.37 221

Red---51 1.28 255

5. After combining the channels, adjust---brightness contrast brightness-3, contrast +16

Select Image---Adjustments---Hue/Saturation---Adjust the saturation to +17 and confirm.