offset printing glossary
Aqueous Coating: Aqueous coating is a water based coating that is applied to full color print projects to provide a high-gloss surface that is resistant to dirt and fingerprint marks. This provides a shiny appearance.
Book Stock: See Paper Stock
CMYK: CMYK, also known as Process Color, is a color model and term that is used to refer to the 4 or full colors of commercial printing. The four colors M-magenta, C-cyan, Y-yellow, and K-black, when mixed to varying degrees, create all the colors in commercial printing. Files submitted for full color commercial printing use the CMYK model. Not all software programs can convert to CMYK so check your software program, before you start on your project. See more information about converting.
Files that are converted from an RGB color space to a CMYK color space will see a distinct shift in color values as you can see below. Photographs will be less noticeable than blocks of color but depending on the image there will be color variations.
Color: 4/4, 4/1, 4/0–These numbers represent the number of colors used in the printing process. 4/4 is full color (4 colors) on both sides of the paper, 4/1 is full color on one side with one color (usually black) on the other and 4/0 means that one side is full color while the other side is blank. If you’re printing a job with spot colors that is not full color printing it would be called 1/0 (one color) 2/0 (2 colors) etc. When a job is ordered in 1, 2, or 3 colors you need to submit the file with PMS colors selected in your file and noted with the order. Do not set CMYK as you would for a full color job.
If your project does not have more than 1 to 3 colors in the file then ordering full color printing may not be your best choice. In most cases 3 colors will be as much or perhaps even more than a full color job, however when a 1 or 2 color piece is all you have you may be better to select a Pantone (PMS) color for the ink you want and design the file accordingly. This is especially true in letterhead and envelope situations when you may have one color and black ink. The colors need to be set in PMS colors and specified within the file.
Color Correction: Computer programs color correct by adjusting, changing, and manipulating color images through retouching and adjusting color balance and saturation. Color correction is not done during the Gang Run printing process so if color is extremely important to you then be sure you get a hardcopy proof as it will be a good representation of what will print in the end.
Color Density: Density is the weight of darkness or color and the degree of tone within a reproduction or photo. It is measured by a densitometer. Like color correction, color density issues are not adjusted during the Gang Run printing process. Files should be adjusted for color density prior to submitting your file if you’re using a gang run process.
C1S or C2S: Is a coating can be applied to one or both sides of the paper. C1S means that coating is on one side of the project. C2S means that coating is on two sides (Coat 2 Sides). If you are planning to mail or write on one of the sides – such as the back of a business card or postcard, don’t have that side printed with a coating. Check with your mail house if you are planning to have your project mailed as some mail houses cannot address properly due to their inkjet labeling process smearing from the finish. Ballpoint pens will also not write effectively on gloss products so if you are mailing the project yourself you will need to use a label instead of hand addressing.
Cover Stock: See Paper Stock
Digital Printing: Digital printing is an imaging process where all graphic content is in digital form from creation to output. There is some debate as to whether the term digital printing means that a digital press is involved, or whether any offset or digital press that is computer automated from start to finish is “digital printing”. Unlike offset printing presses, digital presses can only accommodate a limited paper thickness, kind of paper stock andfinish, and may lose color range. They can be much faster in turnaround than anoffset press and cheaper. Depending on the job and how fast you need it this can be a great option. Check with the printer you want to use to find out if they are running the job offset, or digital.
Digital Proofs: Digital proofs are a way of proofing where the file is converted into a lower resolution.pdf file for you to review. Most online companies prefer the digital proof system because the file can be easily viewed by the customer, it costs less and can be produced within a very short time frame when compared to hardcopy proofing. Digital proofs provide a great representation of what the final product will look like, but they do have some limitations that you should be aware of. If color is extremely important, .pdf proofs are not the best option. Since the file appears as an RGB file that is viewed over your monitor it is impossible to see what the final exact colors will be. Digital proofs are also compressed in resolution so that they are easier to view quickly, but they may appear fuzzy or pixilated. If the image placed in your file was 300 dpi then the final output of the image will be sharp, if the image was 72 dpi then the final output will appear close to the proof image. If either of these is extremely important to the final piece then a hard copy proof is the only way to go.
Die Cutting: is the process where paper is cut in a shape or form. Business card slits in pocket folders are die cut as are the holes in door hangers. Most die cutting is done with a wooden die or block in which are positioned steel rules in the shape of the desired pattern.
DPI: Stands for “dot’s per inch.” The number of dots or pixels in a single inch. The more dot’s the higher the quality of the picture. This will affect the resolution, sharpness and details of the photo. For print 300dpi is standard, sometimes 150 is acceptable but never lower, you may go higher for some situations. For the web: 72dpi or 96dpi. Technically this outdated but we will explore this sometime on the blog.
Embedding Graphics: Images and graphic elements need to be placed or embedded into your design files, not linked. This is crucial when you go to .pdf your document to upload for printing. And be sure all images are 300 dpi and in CMYK color mode. If you’re not sure how to place or embed elements into your program, check the individual help file as all design software programs differ in procedure.
Fonts: Fonts are by definition a set of characters in a specific typeface, at a specific point size and in a specific style. They are also referred to as type and text. When submitting a file for printing, fonts need to be converted to outlines/curves or paths whenever possible. This eliminates problems with embedding fonts when the file is .pdf’d and if you are sending the native file it eliminates the need to send along the fonts. Converting fonts is easily done in programs like InDesign, Illustrator, Photoshop and Quark. Just search under the help menu in your program for more detailed instructions on how to outline your fonts.
Gang Run: Gang run printing is a method where multiple print projects are placed on a common printing sheet to reduce printing costs. The advantage of gang run printing is that it makes full color offset printing extremely economical. Instead of paying for all the set-up costs, prep time, and labor for your job you split the costs between many orders. The disadvantage to gang run printing is that it is hard to accommodate custom orders since paper stocks and color options are limited. A gang run project is also harder to control color quality issues since color balance can be difficult to maintain on gang run projects. Gang runs give you the most economical option for color offset printing, but if color consistency is extremely important you should consider paying the high cost of having your job run as a custom piece or at least get a hardcopy proof.
Hard Copy Proofs: Hard copy proofs are usually created on a high quality printer (not a press) that gives true color calibration to that of what the offset press will print. Images will appear in their highest resolution and colors will be crisp and sharp and true. Hard Copy Proofs take longer to receive from online companies because they must be printed and mailed. Once received, the client will need to sign or accept the proof and some companies may require that you snail mail the proof back with a signature before they will begin to print your job. If color or image quality is extremely important than a hard copy proof is a must.
Image Resolution: Resolution is measured by the number of squares of color information that is held in an inch. It is referred to as “dots per inch” or dpi. Images for commercial printing need to be placed or embedded into your designed files at a high resolution of 300 dpi. Images from the web are usually 72dpi and any image that is less than 300dpi is not suitable to use for commercial printing. Images with a resolution less than 300 dpi will look fuzzy and pixilated with jagged edges in your finished product. If you enlarge an image, you lower the resolution. If you reduce an image you can increase the resolution – so as long as your original image is large enough you can increase the dots per inch and decrease the final size.
How an image was originally acquired will determine its resolution and the size that should be used for printing to ensure a crisp and clear outcome. Resolutions higher than 300 dpi do not improve the image quality enough to make a difference, it will however make a much larger file that takes longer to upload. If you are purchasing stock photography for your project, make sure you purchase the image in a 300dpi format, not 72dpi. If you are taking digital images from your camera, or using a scanner to obtain the image, be sure your settings are calculated for a high resolution of 300dpi.
Lithography: See offset.
Matte Finish: This finish has a satin coating instead of a glossier coating that is applied after the ink has been offset on the paper. This provides a little resistance to dirt and fingerprint marks, but not as much as an aqueous or UV coating.
Offset: Offset or Lithography is a printing technology that dates back to 1798 and encompasses a five step process. Based on the principle that oil and water do not mix, an aluminum or plastic plate is coated with a photopolymer film and exposed to light through a photographic mask. The exposed areas are chemically “hardened,” and the unexposed areas are dissolved when the plate is put through a chemical process. When printing a page, the plate is dampened, and the water adheres only to the unexposed, non-image areas, which repel ink applied to the plate. The most common lithographic printing uses the offset method, in which ink is “offset” onto a rubber-coated cylinder that is pressed against the paper. Offset printing offers the highest quality printing with the most range of products and best color accuracy. It can be more expensive but many printers offer a “gang run” process where your project is grouped with other projects to keep costs low on the highest quality printing available.
Paper Cutting: Paper cutting is usually done in large stacks on machinery. Therefore, it can vary slightly from the top of the stack to the bottom. Although automated cutting machines are state-of-the-art, it’s best to allow some tolerance in your designs to allow for this shift when cutting. Set text and important graphics about a quarter of an inch from the edges and double check that nothing important appears too close to the edge. If you do want a border to appear around the entire outline of your design make it large enough (.25″ or larger) to accommodate shifts during the cutting process.
Paper Stock: Stock is a term used to describe specifications for paper such as thickness (or weight), size, type and opacity. It is often designated by the manufacturer or mill’s name and weight. Stock weights are consistent within the industry so no matter where you have your printing done the thickness will always be the same. There are mainly two types of stock, cover and text (also called book). Text (or book) stock is what is commonly used for pages in magazines, flyers, and brochures. Cover stock is a thicker heavier paper used for brochures, postcards and magazine covers. It is measured in lbs but can also be measured in pt (points).
Paper Weights: 80lb, 100lb, 10pt, 12pt, 14pt These numbers are the thickness or weight of the paper. The higher the weight the heavier the paper is to the touch. A common offset paper at a 60lb thickness and is similar to a 24lb bond that you would find in a local office supply store for stationary. An 80lb or 100lb book (text) weight is perfect for a brochure, flyer, or the interior catalog pages. 10 pt (point), 12 pt and 14pt are another way we measure thicker, heavier stocks. Business cards and postcards can be printed on a range of papers but a 14 pt stock is a great way to go. It’s durable and will make a lasting impression over thinner stocks that bend easily. When selecting full color printing select at least an 80lb book weight for your brochures and flyers so that the colors and images don’t show through the other side when held up against the light.
Pantone: To alleviate problems with color, designers and printers rely on the Pantone Matching System (referred to as PMS colors). Pantone, Inc. is the world-renowned authority on color and provider of color systems. If you’re serious about designing and color is important then purchasing a set of Pantone color swatches is the only way to go. The swatches will give you PMS numbers that you can use to be sure your color appears correctly in your final printed piece.
PDF (Portable Document Format) is a free file format program that was developed by Adobe. A pdf file captures formatting information from publishing applications and makes it possible to send these documents to be emailed, printed commercially, or printed on your desktop printer. PDF documents have changed over time and now most commercial printers prefer to receive files in .pdf format instead of in the native applications. They also send proofs in a .pdf format. Files that are going to be sent to a commercial printer need to be .pdf’d according to the individual printers guidelines.
Rich Black: A term that refers to the mixture of colors (CMYK) used during printing – usually referring to black ink. It is often referred to as a color that is blacker than black, so that too much ink is used. Text should be set in 100% K (black) and 0% for each of Cyan, Magenta and Yellow. For non-text blacks the color selection should not be more than 40% Cyan, 40% Magenta, 30% Yellow, and 100% Black. Some individuals use rich black for small areas of black to avoid trapping issues, but most times the rich black becomes an issue when files are converted from RGB to CMYK.
RGB: RGB is the color space that refers to the three primary colors; Red, Green, and Blue. Computer monitors, scanners, and digital cameras use a combination of red, green and blue light to create and display images. Commercial printing uses CMYK as described above. This is why what you see on your screen will not match what is commercially printed. There are special software programs available to calibrate your devices but the only way to be certain the colors you want are produced is to use the Pantone Matching Color System.
Staccato screening: Staccato screening is a state-of-the art technology that produces images that closely approximate continuous tone resolution and surpass the quality possible with conventional screening technologies. Some higher end printers have this technology so check before you buy.
Text Stock: See Paper Stock
UV Coating: UV Coating is a heavy, very slick glossy coating that is applied to the printed paper after the ink. The slick and very glossy surface makes it very eye catching and the most resistant coating to dirt and fingerprint marks.