Business Card Design and Printing

Chapter 3

Inks may be either opaque or transparent. Although there are many uses for both, the bulk of printing and all reproduction of colored pictorial material, such as art work or photography by process printing, require transparent inks. Such reproduction utilizes the three transparent subtractive secondary colors (plus black generally) to reproduce all the colors of the original.

Reproduction by process printing requires use of the subtractive secondary colors (and often black to deepen shadow areas or to increase contrast). The colors are yellow, magenta and cyan. When they are combined, you see several colors- but it is called a three color reproduction. (See Figure 2)
A colored transparent ink film modifies light by subtracting from the light source certain wave lengths and transmitting others. Just as the green bottle subtracts red and blue and transmits green as in Figure 4.

Opaque inks, like the apple, reflect light; no light passes through them. Transparent inks, unlike the red apple, allow light to pass through them. (See Figure 3)

But transparent inks obviously are not suspended in mid-air between a light source and the eye as a piece of colored glass might be. Rather, they lie flat against a sheet of paper.

The paper then becomes the reflecting light source for the ink placed on it. (See Figure 17)
When transparent ink films are overlapped, as in process printing, they produce intermediate colors because each film layer allows light to pass through it. On the other hand, overlapped opaque colors reflect light, they do not transmit or pass light and so do not produce intermediate colors when they overlap. Silk screen printing lays down thick opaque films of ink. Overprinting completely hides the color underneath. (See Figure 18)

Theoretically, perfect process ink subtractive secondary colors, capable of reproducing most of the other colors of the spectrum, are:
Cyan- (absorbs all red and transmits blue/green)
Magenta- (absorbs all green and transmits blue/red)
Yellow-(absorbs all blue and transmits green/red)
Unfortunately, there are no perfect process inks, and ink formulations are varied to best satisfy particular requirements.

Additional correction and adjustment in preparatory photographic and platemaking steps prior to printing must be made to compensate for ink limitations in order to obtain the most accurate results.
Beyond this, the three process printing inks do not have the same reproductive range as some art mediums, such as oil base paints; nor can they reproduce all the subtle hue and value variations found in some colored originals.

This is why some reproductions are often less brilliant than the originals.
The introduction of the Halftone Screen compresses the tonal range or range of values available in a printed reproduction, because the minute unprinted areas of the white paper reflect white light and dilute the print. Addition of white light raises the value of color and decreases its saturation or purity.
In spite of the limitations of the inks, and other factors such as plates, blankets and the halftone screen, color reproductions can be amazingly accurate.