Digital Printing

A printing process that uses inkjet technologies to produce the images, as opposed to printing plates or silk screens. This allows variable data to be used on each image, and makes for more affordable printing of short runs, especially in large format sizes.

Graphics

DPI:
Dots per inch, a measure of picture resolution or printer dot density. The higher the DPI, the finer the image will be. Generally, 300 dpi is considered minimum for production of magazines but in large format printing, 100-150 dpi is considered adequate at printed size. This is due to the distance from which the prints are usually viewed. DPI is also used to judge the quality of images in printing files.

Pixel:
A single dot of color in an image. A 2 megapixel image has 1,920,000 pixels (1200×1600 pixels).

RGB:
The Red-Green-Blue color space. Typically used in monitors and digital cameras, colors are described in as 0-256 steps of each of the three colors, describing 16.7 million colors. Pure black would be 0-0-0 and white 256-256-256.

CMYK:
The Cyan-Magenta-Yellow and Black color space, usually associated with four color printing. Colors are described in 0-100 steps of the four colors. CMYK is subtractive color, so that pure black is 0-0-0-100 and pure white is 0-0-0-0.

Color Profile:
Color profiles are generated for printer and paper combinations so that accurate reproduction of colors is possible. They are also very useful in obtaining color matches between monitors and printers, so that what is seen on the screen is what indeed comes off the printer.

TIFF Image:
File format for images based on the Tagged Image File Format standard. TIFF files often have a .tif extension. They can be saved uncompressed or with LZW (lossless) compression without degradation of the image.

JPEG Image:
Pronounced jay-peg, and usually with a .jpg file extension. File format for images that uses color compression to reduce the size of image files. Most digital cameras take a JPG image. The amount of compression can be adjusted. JPG files typically achieve 10:1 reduction in file size with little noticeable loss in image quality.

Image Resolution:
Usually expressed as pixel density (dots per inch) or image size (pixels high x pixels wide). Images can also be expressed as the total number of pixels, as in a 2 megapixel image.

Resampling:
Images are often resampled when being enlarged to large sizes. Otherwise, the pixels can get to a size where they are noticeable. Resampling can soften images, especially at sharp borders between colors, but can usually be done by someone knowledgeable without serious image degradation.

Printer

Thermal Inkjet Printing:
Ink drops are expelled from a printhead by generating a small bubble of steam with a pulse of electricity.

Piezo Inkjet Printing:
Ink drops are expelled from a printhead by the activation of a piezo crystal with a pulse of electricity. These print heads generally last much longer than thermal print heads, and are more expensive.

UV Curable Inkjet Printing:
This process uses UV lights on either side of the print carriage to cure the inks deposited on the substrate by piezo print heads. One advantage of this process is that it can print on flat sheets, and it is the predominant technology used in flatbed printing.

Flatbed Printing:
Printing directly to flat sheets of material, such as coroplast, sintra, 50 point board, and styrene.

Digitally Printed Wallpaper:
Wallpaper in short runs can be done very effectively with UV curable printing equipment. Photos and digital art can be blown up to wall size for striking results in both commercial and residential applications. The material is durable, the colors are accurate and vivid.

Digitally Printed Fabric:
Short runs of custom printed fabric can be done with digital methods. This is typically done with dye sublimation, where the image is mirror printed on a special paper, and then the paper and fabric are run together through hot rollers. The application of heat transfers the image to the fabric. Alternately, UV curable printing can apply an image directly to the fabric.

Dye Sublimation Printing:
An image is mirror printed on a special paper, and then the paper and fabric are run together through hot rollers. The application of heat transfers the image to the fabric.

Solvent Printing:
Inkjet printing with piezo printheads and inks that use a solvent instead of water to carry the pigments. The solvent evaporates off of the media, leaving the pigments. The pigments are not water soluble, making the output waterproof. This is a common process for making outdoor banners.

Materials

Laminating:
Covering a print with plastic or a liquid that hardens to protect the print. Many types of laminate, both cold and hot applied, are available.

Archival Ink:
Inks that are resistant to UV light and thus much more fade resistant than ordinary ink.

Giclee:
A term used to describe inkjet prints, most often associated with fine art reproduction.

Fine Art Reproduction:
Producing prints with great attention paid to accurate color reproduction so as to accurately reproduce the painting, etc.

Foam Core Board:
A product that has a piece of paper on either side of a thickness of styrofoam. Usually used for short duration signage, such as meeting and event signs that will stand on an easel. Foamcore board will warp with changes in humidity, and is not recommended for permanent displays.

Gatorboard®:
A branded product of International Paper consisting of a layer of moisture impregnated paper on either side of a thickness of styrofoam.

Ultra Board:
A product similar to foam core board, except with a sheet of styrene on either side of a thickness of styrofoam. It is much less susceptible to warping with changes in humidity.

Sintra®:
A foamed PVC board used extensively in sign making. It comes in thicknesses up to 1.5″.

50 Point Board:
A 100% recycled board named for it’s thickness, .050″. Commonly used for 22×28 signs going into sign stands. It can also be recycled with cardboard.

Coroplast:
A fluted plastic product often called “plastic cardboard”. The plastic used is polypropylene. It is an affordable sign making product.

Styrene:
A plastic used extensively in sign making due to its low cost, durability, and ease of cutting.