الورق الحساس الملون للتكبير من سلبية ملونة ١-a

Second: Color sensitive paper to enlarge a colored negative:

To understand the structure and how the color sensitive paper responds to the light of the magnifier one must

study :

1- Some information about light.

2- Installing the colored negative film. 3- Attaching colored sensitive paper

1- Some information about light

It is if white light passes through a prism, we will find that it decomposes into the seven known spectrum colors. It was found that white light can be composed of only three colors red, blue and green. These colors are called primary, main, or additive colors. They are called colors of addition because by adding a ray of each of these colors to each other, we get white light. To do this we need three light sources and a filter of a primary color is placed in front of each of them. By mixing these colored rays in different proportions, we can obtain all colors. For example, if we mix two rays with only the primary colored rays, we will get three new colors: - From

Red + green - yellow

Red + blue - scarlet or magenta Green + blue - bluish green or cyan. .

These new colors are called complementary colors because each of them complements one of the primary colors to produce white light:

Subtractive And now we go back to the complementary colors or the colors of yellow, bluish green, cyan, scarlet, or magenta.

Now let's see what can happen if we use one light source. If we put a filter in a primary color (red for example) under the light source (in a magnifier, for example), it will filter the white light and allow the passage of red light only and prevent the passage of blue and green light. And if we put another filter under the red filter (for example, blue), it will prevent the passage of red light as well, and thus we find that we have prevented the passage of all rays and we could not obtain other colors, and this is the reason why the addition magnifiers must have three light sources or display the paper three times, each Once with a different first filter. This is why they are called addition amplifiers because we add rays to each other.

The reason why they are called complementary colors has already been explained. It is called the colors of elimination because by placing one of these filters (yellow, for example) under the light source in the amplifier, it deletes one of the primary colors (in this case, it will delete the blue color) and allows the rays that make up its color to pass through (yellow consists of red and green). And if we put a second filter under the first filter (magenta, for example), it will prevent the passage of green light and allow the passage of red light (as it prevented the passage of blue light before). Thus, we see that by using one light source with deletion filters, we can obtain all colors by using different complementary color filters. And due to the ease of making a magnifier with one light source, the magnifiers are the most widespread and common. The deletion is

Thus, we find that there is an important color tradition that is the basis of color photography. I hope that you always keep it in your mind so that you can enlarge color pictures easily. These colors are:

A - Additional colors or primary colors: red - green - blue. b - Omitting or complementary colors: yellow - magenta - cyan

2- Installing the colored negative film

In black and white films, every white in nature appears to be black in film and every black appears to be white. As for the colors, they appear in different degrees of gray, as the light gray appears in the film, and vice versa. The same thing happens in color films except that the colors appear in the film in a color complementary to the color of nature, for example