Chapter Two

Halftone Dots

            Because a printing press cannot print many different shades of ink, halftone dots are used to achieve the depth of printing detail needed. Halftone dots simulate the different shades by changing the size of the dots.

Dots Per Inch (DPI)

DPI describes the resolution of an imaging device like a printer. Depending on the device the DPI commonly can range from 600 DPI to 2400 DPI.

Lines Per Inch (LPI)

The measure of a halftone dot is called screen ruling, or screen frequency, and this measurement is usually expressed by LPI. The LPI is the frequency at which the halftone dots occur.

Pixels Per Inch (PPI)

            The PPI directly relates to the resolution of the image. A good quality image is typically printed at a resolution of 300 PPI.

CMYK vs. RGB

            CMYK is the four-ink color process using the colors Cyan, Magenta, Yellow, and Black. Using halftone dots these four colors can be combined while printing to make up a very wide range of colors.

          

            RGB is the acronym used for the three-color system of red, green, and blue that can be displayed on the computer monitor.            

Spot Colors

            Spot colors are colors that are individually mixed to obtain colors that fall outside of the CMYK color range or are specially mixed to insure that a specific color is achieved every single time the color is printed. A popular creator of Spot Colors is Pantone, a company that creates swatch books for designers to view color and select their choice from. While only using one to two spot colors for a job may be a money saving technique, adding a spot color to a CMYK job will add an additional color to the cost and may even cause a second run to be made on the job.

Registration

            Most readers may easily overlook registration marks on a printed document, but these marks play a vital role in printing. A printer needs these marks to be sure that the ink is printing in the right locations after subsequent productions.

Rich Black

           
A printed area of black that is larger than one square inch needs to use rich black to resist the appearance of being weak. A combination of the three other process colors, cyan, magenta, and yellow are used to prevent this fading from happening.

 

 Color Management

           
Managing color can be difficult and expensive, but it is a necessary task to produce quality designs and prints. Devices must be inspected with equipment to ensure that the color display is functioning properly. While not everyone has access to expensive calibrating equipment, there are things that can be done to achieve quality color at home. Avoiding monitor glare is a simple, yet beneficial tip I use to avoid color mistakes.

All information and images were obtained from Print Production with Adobe Creative Suite Applications.