Printing Terms
Common Printing Terminology
This is a continual work-in-progress, so if you hear a term from your print shop that needs to be added, or if you see something here that isn’t very clear, let me know. I have defined all of these to the best of my abilities and no doubt have probably caused confusion or at the very least, lacked clarity on something.
Bleed: The area outside of final trim size where graphics must be to ensure a clean cut with graphics going all the way to the edge of the trim. Typically 1/8″ (.125″) is recommended for all projects
Calibration: The result of calibrating. No, seriously…calibration is key in the digital world. The simplest explanation I can think of for calibration is measuring and adjusting a device to conform to a given set of standards or guidelines. Everything in a print shop needs to be calibrated, including, but not limited to: monitors, platesetters, scanners, cameras, presses, and on and on…
CMYK: An acronym for Cyan, Magenta, Yellow and Black. Black is K. I don’t know why. Any “full color” printing will be built with these four process colors by varying the size of the dots that are printed.
Color Gamut: This is a good one. A color gamut is the visible range of colors that can be produced by given method of color reproduction. Not all colors that you see can be reproduced by any single means. For example: the range of colors that can be produced by 4-color process inks is a much smaller range than what the human eye can see, and it is different still from the range of colors your monitor produces. The desktop printer sitting beside you can only produce a certain range of colors also. This is one of the single hardest concepts for most people to understand and probably the most frustrating limitation of full color printing. The digital age has brought upon us wonderful tools and systems, but at this point it is still limited when color accuracy across different mediums is concerned. Contact me if you have specific questions about this and I’ll do my best to explain why things are the way they are.
Contract Proof: This really only applies to full color printing. A contract proof is a very accurate representation of press output of your project that you will usually sign and confirm as being what you expect your project to look like. I say “very” because no matter what cool technology comes down the road, unless that proof is printed on the press with process inks and on the very same paper your project specifies, it will never be 100% accurate. I take a somewhat cynical stand on this particular topic because I have heard and seen way too many vendors and printers claiming perfect color proofs, and let me tell you right now, there are too many variables. I can tell you from personal experience in setting up and calibrating the color proofing system in our print shop AND having a background in professional photography, that it just cannot be achieved at the level that I call 100% accurate. With that being said, very few people will notice some of the differences between the contract proof and final printed piece, but don’t let anyone tell you their proof is 100% accurate if it’s not from the press.
Creep: When you design a booklet that is to be saddle stitched (stapled together on the spine), you should always be aware that the more pages are in the book, the resulting thickness of the area where the staple passes through is also thicker when the book is folded and the center pages stick out further than the outside pages. This is called creep. When you receive your finished book, the edge is flat and square because that excess has been trimmed off during the booklet-making process. If you disassemble the book and measure the pages, you will notice the center pages are shorter than the outside pages of a gradual progression. If you have page numbers too close to the edge, you will notice that they are much closer to the edge on the center pages than the outside pages. Print shops can usually correct for this as long as your design does not have images or text that cross-over the fold on any of the pages. If that happens, there’s little that can be done to correct for creep. Talk to your print shop or contact me before you get too deep into a book project and we can help guide you through how to avoid some of the issues with creep.
Crossovers: Open a magazine and find a spread where the image or text goes from the left page all the way onto the right page. That is a crossover, the image or text crosses over the fold onto the next page. If you are creating a booklet or book that is going to have this type of effect, PLEASE talk to me or your print shop prior to submitting those files. There can be serious limitations and issues with that effect depending on how your book is going to be bound and finished.
Dot Gain: This mystical phenomenon is one of those things I can’t think too much about or else my head starts to hurt. Dot gain is a calculation, based on percentages, of how much the actual ink dot spreads into the different types of paper versus the true size of the dot on the printing plate. I cannot tell you how many threads I’ve read, nor do I wish to revisit the multitude of discussion forums related to this topic. Here’s what you need to know: colors change based on the type of paper and surface coating on each paper. The same project printed on uncoated and coated papers will look different because of how much ink is absorbed into each paper type. Dot gain adjustments are supposed to offset this, but nothing I have ever seen leads me to believe that you can achieve identical color on coated and uncoated papers. Call me a skeptic.
Finished Size: This term is too vague and sometimes stirs confusion. It is often used interchangeably with flat size or trim size and can even be thought of as folded size. It is best to use other terminology since this one has too many implications depending on who you are talking with.
Folded Size: Folded size is another term that is more accurate than “finished size”. It is exactly what it sounds like. If you have a brochure that requires folding, then the folded size will be different from the trim size.
Folding: This really doesn’t need much explaining with the exception that you need to be VERY familiar with the measurements and types of folding your project requires, along with the limitations of those types of folds. Please see the Templates page for examples with measurements.
Gang Run: A gang run is when separate, unrelated jobs with similar quantities are all put together on the same large press sheet to run together, minimizing setup times, paper waste, and cost. The upside to this technique is that prices are lower and many online print shops can gang run multiple jobs and you get the savings. The downside is that now your job may not get the personal attention needed to ensure consistent, pleasing color when it’s combined with several other jobs on the same sheet.
Hard Proof: This is simply a printed version of your project. This term is sometimes used interchangeably with “mechanical”, although a hard proof can be color accurate and a true representation of what your final piece will look like. Always ask when viewing a hard proof if it is color accurate.
Mechanical: Today’s definition of a mechanical is simply a printed version of your project, usually folded, etc. for you to review. It is a close representation of your final piece with the typical exception of color accuracy. In some cases, the mechanical is the actual printed copy that you take in (i.e., a business form) that is “photographed” for plate production, although that technology has been all but completely replaced with digital workflows. The likely scenario in today’s printing environment is that your document would be scanned and digitally output.
Offset: Offset is what happens when a printed piece is placed on top of another printed piece before the ink is fully dry and the ink is subsequently transferred. It’s not a good thing, but it does happen. I’ve seen entire print runs get tossed into the recycling bin because of this. Unfortunately, a myriad of factors can cause this to occur. Paper type, ink coverage, type of ink, press speed and even humidity levels can contribute to this. It is avoidable and most shops know how to avoid it, but you need to know what it is.
Overs: This is an industry term that most likely applies to other industries as well. Overs are the extra sheets printed that are needed for setting up the press run and later used to set up the cutting, folding and other bindery equipment so that your final quantity will not be affected. There is no set formula for determining the number of extra sheets to order and run. A lot of it is based on complexity of the job, finishing tasks required for the job and sometimes simply a gut feeling from the press operator on how well the job is running on the press. The bottom line is that if you order 500 of something, enough extra paper is printed to ensure that you receive at minimum 500 finished pieces.
Plate: Also known as a printing plate. A printing plate can be made of several different substrates such as paper-based, polyester and aluminum. The plate is a flexible, flat piece of material with the image of your project burned, etched, or printed onto the surface. This surface transfers ink to the blanket and in turn onto the paper in the printing press. It’s not very exciting, but producing plates is one of the processes that has turned the printing industry on it’s ear over the last decade or so. Technology in this single area has made affordable full color printing more available and very competitive in recent years.
PMS Color: PMS is an acronym for an industry standard library of spot colors. It stands for Pantone Matching System.
Preflight: This is another cool word that has borne from the digital age. Preflighting means inspecting your file with specialized software that checks for and reports errors and warnings based on a given set of parameters. If you send in a file that you want printed in 4-color process, the software will analyze that document and tell the prepress department if everything in that file meets the requirements for 4-color process printing. For instance, if your document contains a spot color, the software will let us know so we can contact you and ask if you’d like us to convert the colors, or if you’d prefer to change things yourself. It also analyzes fonts, graphics and photos for resolution and sometimes it will even produce a decent cup of coffee for us while we wait. That was a joke.
Press Proof: When color is critical and you may not be sure of the results, a press proof is the way to go if your budget and the printing company allows it. A press proof is an actual sheet that has come off the press at the beginning of the run. It will undoubtedly give you an accurate result of the colors in your final piece because, well…it is your final piece. A press proof (if available) can be expensive because you are essentially shutting down the press while you inspect the printed sample. If there are changes to anything on the project at this point, be ready to fork over more money because now you have halted the press run and everything has to start over. But, if color is paramount, this is truly the only way to know for sure how the colors are going to look. It is less expensive than reprinting the whole project, but I don’t recommend it unless you have a healthy budget and dire need to get the color perfect.
Process Color: Process color differs from spot color in a very significant way. Process refers to using the 4 process colors (Cyan, Magenta, Yellow and Black) to produce full color printing. Not all spot colors can be reproduced with 4-color process printing. Talk to your print shop or contact me for questions you may have about this.
RGB: An acronym for Red, Green and Blue. RGB is what you see while reading this web page. I believe all color electronic display devices use this form of building colors. See Color Gamut for how this relates to printing.
RIP: Another acronym, Raster Image Processor. This is a piece of software in print companies that analyze and separate the colors in your project so they will print correctly when recombined on the press. It’s a bit more complex than that, but I don’t want you to fall asleep reading this.
Scoring: Believe it or not, all paper cannot be folded cleanly and accurately without scoring first. Scoring is a process which in effect, puts a crease along the line where the fold occurs. There are many ways this can be accomplished and not all of them can be performed accurately and efficiently by a machine. Be sure and check with your print shop when choosing your paper to ask if it needs to be scored before folding and if it can be handled by their machines. Sometimes this type of work must be performed by hand to produce a quality product and that can add to the cost of a seemingly simple project.
Separations: Any printing project that consists of more than 1 color must be separated into each color so that each color can be produced on it’s very own printing plate. If you have an envelope that is red and black, chances are good that 2 printing plates were produced to print that envelope, one for the red and one for the black (assuming it’s not a 4-color red). In 4-color process printing, 4 printing plates are produced. One for each of the process colors, cyan, magenta, yellow and black.
Shells: This is a term that the logical part of my brain has never fully liked. A “shell” is a preprinted template that can be printed on again in the future. An example is needed… Think of a church bulletin with a lovely color picture of the steeple on the cover. Now since that image won’t likely change over the course of, let’s say one year, it would be foolish to print that full color cover every week just because the text inside is going to change. So the smart decision is to print a large run of “shells”, which is just the full-color outside of the bulletin, in large quantities to last the year. Then, as needed, you can submit files to the print shop to print the text inside the bulletin, normally in a single color. This concept gives you the flexibility to have a top notch design and have it updated regularly without breaking the bank. If you think your project could potentially be a shell project, contact me and I’ll be happy to answer any questions you may have and guide you through the process.
Soft Proof: This term is a reflection of the digital age in printing and refers to an electronic version of your document that you would review on your monitor. The type of file you view as a soft proof will most likely be a PDF, but could be a JPG, EPS, TIF or another graphic file type.
Please note: color accuracy when viewing a soft proof is purely dependent on your monitor and viewing environment, and unless your monitor and viewing environment are calibrated for color accuracy, your printed project will not match your screen!
Spot Color: A spot color is primarily a single ink color made with mixing tints to a specific formula. That mixed ink is then put into the press to print onto the paper.
Trapping: When you have 2 colors (mainly spot colors) that touch each other or lie on top of each other on your project, each of those colors is output on a separate printing plate and it is the press operator’s job to make sure they line up. However, sometimes you will see a white line where the 2 colors should be right up against each other. Due to the mechanical nature of machines in general and a whole host of other variables, sometimes it’s just not possible to line those colors up perfectly. This is where trapping comes into play. In the digital world, specialized software has the ability to recognize those colors that are touching and create a minute spread of one or both of those colors along the path where they intersect and allow the tiny edges to overlap rather than butt up against one another. While it is rarely advantageous to completely print one solid spot color over another, the technique of trapping ensures a gap-less seam of ink on top of ink without adversely affecting the spot colors involved.
Trim Size: Also referred to as flat size and finished size. “Trim size” is a more accurate term because it means your project has not been folded or otherwise manipulated. This is the size of your document after all the cutting has been performed and that is where it stops.
