About Prepress
Before a piece is even designed, its important to understand several key areas. First and foremost, I would suggest that you need to have an idea of what you are trying to accomplish with your piece and how much you can afford to spend for printing. These factors will greatly impact the design. How many colours should you use? Should you use process colours, PMS/spot colours, or just coloured paper? What paper weight should you use? Should it be coated or uncoated? Will you be using envelopes? Will a certain paper adversely affect halftone reproduction?
There's a long list of things to ask your prospective printer and several things that your printer will need to know about your project. Your printer may often be able to make suggestions for keeping your printing costs low. Even if your budget won't permit you to use a lot of colour or expensive paper, there are still ways, through duotones or tritones for example, to produce professional and interesting designs. Different forms of varnishing could be a consideration.
Once a piece is off the press, the production process doesn't have to end there. There are many forms of finishing such as binding, scoring and cutting that can be taken into consideration to make a piece more interesting and effective.
How can you tell if a printer is right for you? One of the ways that you can tell is through their equipment and the method that will be used to print your piece. There are a lot of different ways to print a piece and it's in your best interests to know about each method. Common methods of printing include Letterpress, Flexography, Gravure/Rotogravure, Engraving/Thermography, Offset Lithography and Silkscreen. For short-run printing you might want to consider photocopying, direct-to-plate or digital printing. Web printing might be something to consider for large print runs.
The bottom line is communication. By understanding the different components of printing and by talking to your prospective printer, you'll be far more likely to avoid big and costly headaches in the the end.
When someone tells you that a printing job is a two colour job and that it's printed on creme paper, does that mean that it uses one ink colour and the stock colour?
In a word, no. When a printer or designer talks about a two-coloured job, they are referring to the number of colours of ink on the press. (Yes, black counts as a colour.) One could be using rainbow coloured stock with black ink and it would still be a one-colour job. With the exception of the extra cost of paper stock (rainbow trees don't come cheap), the job would cost the same as if you were printing on white paper.
What can be deceiving sometimes is if a designer uses a very light tint of one of the ink colours on the background of a page so that appears that the stock is a different colour than what it truly is. One can tell if this being done by taking a printer's loop or magnifying glass and looking very closely at the paper to see if there's a fine dot pattern.
There isn't a simple black and white answer to this question (pun intended). The real issue is "How many inks should I use?" A brochure might appear to be using dozens of colours but it's only using four process inks while an eight-colour brochure appears to be using half that many colours.
There are basically two colour printing methods to choose from: process-colour printing and spot-colour printing. Each method has its advantages and disadvantages.
Process Colour Printing With process printing, one has the flexibility of a wide spectrum of colour choices. This is also the printing method that will allow one to use full-colour photographs while paying for just four inks (cyan, magenta, yellow and black). The only downside to this method is that colours aren't nearly as vibrant as spot colours and a designer may not be able to match a particular colour exactly.
Spot Colour Printing Typically, spot colour printing uses a coloured ink system known as the Pantone Matching System (PMS). There are hundreds of colours to choose from in this system and some include extra bright colours, dark colours, fluorescent and even metallic colours. Basically, any colour you can imagine, you can find as a spot colour choice. The downside is that, no matter how many spot colours are used, you can't create full-colour photographs.
Can you use both process and spot colours? Certainly. People do it all the time. However, the more inks that you use, the more expensive the cost to print it. Before a job is designed, it's a good idea to talk to your printer and to your designer. They can help you decide how many colours you can afford and how many are needed to accomplish your goals. Whatever your choice, with solid planning, you'll be able to make the most of what your budget can afford by using colours effectively.
If you've ever visited a paper store, you've probably noticed that there are dozens of shades of white paper. Some white paper has a soft creme colouring while others are a soft gray, soft blue or even a soft pink. Viewed separately, these papers each appear to be white but, viewed next to other white papers, it's easy to see the vast colour difference.
You can probably guess that one stock has a coating of some kind and that the other paper doesn't. But, what does that mean in terms of your printing job? What should someone be aware of? Here's the difference.
Uncoated papers have a rough, more natural feel to them. Examples of uncoated stock are newsprint, cheaper catalogs, many recycled papers and most papers available in a local copy shop. These papers tend to be more porous and soak up ink. Depending on the quality of the paper, they can soak up a LOT of ink.
Uncoated stocks are ideal for quick and less-precise printing. They are also ideal for pieces printed for people to write on or read for an extended period of time (so there won't be any glare to irritate a reader's eyes). Uncoated stocks tend to be less expensive than coated papers and are perfect for newspaper and flyer printing.
Coated papers, by contrast, have a smoother finish and are not very porous at all. Ink will, more or less, sit on this type of paper's surface. It will take longer for ink printed on a coated stock to dry. Type and photographs look sharper on coated stocks because the ink doesn't bleed into the paper and blur the halftone screen. Detail is not lost and fine text holds up well. Keep in mind though that some coated stocks are very difficult to write on or to read from. Coated papers also tend to be more expensive than uncoated stocks.
Though coated paper can come in a dull or glossy finish, this shouldn't be confused with a varnish or a plastic lamination. These are separate processes that are added at the end of a job. They can add an extra bit of gloss or durability to a printed piece that regular inks can't provide. Though a lamination can work well with either a coated or uncoated stock (make sure you don't have too much gloss), varnishes are only effective on coated stocks. A varnish will soak into an uncoated stock so one won't be able to tell a varnish has even been applied.
So, if one is looking to print something in a very large quantity that is meant to be written on or read from (books, newspapers, forms, flyers, etc.), an uncoated stock is a viable choice. If one is looking to print a high-impact piece (a brochure, catalog, or mailer), then a coated paper may be the better solution.
Say you need 15,000 copies of a black and white letter. Or, maybe you need 500 copies of a full-colour sales sheet. Should you photocopy or print them? With copiers becoming more sophisticated all the time, the line between copying and printing is becoming much more blurry. Here are the strengths and weaknesses of each option in terms of three important considerations:
Photocopying (which includes "digital printing" for the purposes of this article)
Time: Copying can usually give you a fast turnaround of small, or even large, quantities. A copy shop usually has several machines ready to work as soon as you walk through the door. There's also no costly preparation involved.
Money: Typically there's a fixed price associated with each copy. This makes photocopying ideal for lower quantities but quite expensive for larger quantities.
Quality: Though photocopiers have come a long way, printing still wins the prize for quality. Toner can chip off and typically photo reproduction quality is second grade comparatively. You'll also have fewer choices in terms of paper stock. Linens, in particular, do not work well for photocopying.
Printing
Time: Typically, a printing job will take longer as there's some "pre-press work" to be done. Direct-to-Plate printing cuts a lot of time and money out of this process. A print shop will usually have only a few presses at their disposal so your project will have to wait in line behind jobs that came in before it.
Money: Because of the higher costs of the press, film and plates, you can expect to pay more for a printed job. A high print quantity will offset these costs and will result in your paying less per piece as the quantity rises. Again, direct-to-plate printing, because you don't have to pay for film, can bring the price of smaller quantities way down.
Quality: The quality of the printed product is far superior, in most cases, to photocopying. You'll also be able to choose from a much wider variety of paper stocks.
But, what if it's simply a question of price? Let's go back to the scenarios in the first paragraph. If you need 15,000 of a black and white sheet, should you print it or copy it? How do you figure it out? Quite easily actually. Call the people doing your printing or copying and get prices from person/company for your specific quantity. Divide each price by the quantity (15,000 in this case) and you'll have the "per-piece price" for both printing and copying. In this case:
Printing: $450/15,000 = $.03 per piece - the price winner
Copying: $750/15,000 = $.05 per piece
Okay, how about our 500 colour sales sheet example? Printing will give you the best quality product but are you willing to pay for it? Let's take a look at some figures.
Printing: $750/500 = $1.50 per piece
Copying: $500/500 = $1.00 per piece - the price winner
It all comes down to some pretty simple math. Keep in mind that this article and these prices were written to give you an idea of how to figure out the best method for your project. There are many variables to take into consideration (digital printing, cheap printing, in-house copying, etc.) but hopefully you now have a better idea of how to approach the decision.
Letterpress is the oldest form of printing. When a person outside of the industry thinks of printing, typically they're thinking of letterpress printing. The process is one of the easiest to understand.
Letterpress printing starts with a single piece or multiple pieces of metal (or wood) made up of an image or letters of type on a printing plate. The area that is intended to be printed is raised up higher than other areas of the plate. Ink is applied by rollers onto the raised surfaces. The raised surfaces then press on paper and the ink, from the raised areas, is left on the paper. The print quality can be sharp and clear but can vary depending on the quality and texture of the paper. Typically only spot colours are used with this method.
Letterpress, also known as relief printing, is pretty rare today but can still be found in oldstyle print shops and in school woodshops. Some use this process as an artform to produce limited edition books and prints.
Like letterpress printing before it, flexography works on the principal of raised items on a plate catching ink and then touching the paper to make the printed impression. As the name suggests, the plates are made from flexible materials like rubber and can conform to uneven surfaces. Typically, only spot colours are used with this process.
Flexography has recently become more popular as a printing alternative because it uses water-based inks. Other printing processes typically depend on oil-based inks. Flexography was only used to print on surfaces like cardboard boxes, plastic cartons and bags. The process has seen great improvements and is now used on more mainstream materials.
Gravure printing works on the opposite concept of letterpress printing. With gravure printing, etched areas are the ones that will create impressions on the paper's surface. These areas are recessed into a metal plate to create tiny wells. These collect ink when an inked roller passes over them. The printing plate is covered with these wells which, depending on their depth and size, control the amount of ink transferred to the paper when pressed against the plate.
This process works well for photographs but the setup can be expensive. The costs become reasonable only when used in large print runs like those of magazines and newspapers. Either spot colour or CMYK colours can be used with this printing process.
Rotogravure printing is the same process but differs in that the paper comes from large rolls rather than sheets.
Engraving and thermography are actually quite different from one another but these two printing methods are frequently confused. The printing results can be somewhat similar and can commonly be found on wedding invitations, business cards and the occasional letterhead.
Engraving is a kind of gravure printing wherein paper is pushed against a recessed plate. In engraving, the paper is usually slightly moist. The pressure of another cylinder forces the ink from the recessed area onto the paper. The pressure of the press raises the imprinted area slightly which gives the piece what we recognized as an engraved appearance.
Thermography, also known as the "poor man's engraving" method, is somewhat similar to engraving in result but not process. It's cheaper and easier to produce than traditional engraving which may account in part for it's popularity. Thermography is created by adding a powder to the ink being printed on a paper's surface. The printed piece is then passed under heat and literally cooked together. When heated (it's thermography after all), the ink and powder blend and rise to give a raised effect. Frequently thermography appears even more engraved than some engraved printing.
In offset lithography (also known as plantographic) printing, plates carry both the image and non-image areas on the same level (unlike letterpress where areas are raised to catch ink). The transfer of ink is controlled by an unlikely principle. The principle that oil and water don't mix.
Image areas are photographically transferred to thin metal plates which are treated chemically to accept oil-based ink but repel water on the image areas. Conversely, non-image areas accept water but repel the oil-based ink.
A plate first contacts rollers of a clean solution or water and then is inked by other rollers. The oil-based ink "sticks" to the image area. The inked image is then transferred from the plate to a rubber blanket. The rubber blanket then transfers the image onto the paper's surface.
Because of the resilience of the rubber blanket, it's possible to use offset lithography printing on a wide variety of surfaces and for large quantities. Both spot colours and CMYK colours can be used with this process.
Screen (or silkscreen, as it is sometimes called) printing primarily uses a hand or electronically-prepared stencil. The part that is to be printed is made up of silk, nylon or a stainless-steel mesh. Ink can pass through this area but not through the other part of the stencil which is contained inside a frame. The printing surface is placed under the frame on a flat surface. The impression is made by forcing the ink through the screen area with a rubber squeegee.
The need for a heavy ink consistency and, as you might expect, a course halftone screen restricts reproduction quality. However, the process offers high-opacity and brilliant colour possibilities. The process is ideal for banners, T-shirts, posters and most any other surface you can think of. The downside is that it is not a highly automated process and the amount of detail one can achieve is somewhat limited. Like letterpress printing, this process is very popular in school workshops.
Direct-to-plate and digital printing have not been around very long but they've very quickly become popular methods for printing low-quantity, full-colour (CMYK) projects.
Direct-to-plate printing, also known as computer-to-plate printing, cuts out one of the steps involved in traditional printing. In traditional offset lithography printing, film is produced (today usually from a computer file) on an imagesetter and then a metal printing plate is made from that. From there, the plate goes on the press and is utilized to make the printed impressions. In direct-to-plate printing, the printing plate is made directly from the computer file which eliminates the need for film. The production of film costs time and money which is why direct-to-plate printing is so popular for low quantity jobs.
The downside to this process is that film was traditionally used to make colour correct proofs (chromalins, colour keys, etc.) that one could inspect before the job went to press. In direct-to-press printing, there's no film so this type of proof isn't possible. Instead, one can get a digital proof can be very close to the quality of a more traditional proof. Digital proofs are cheaper to produce than a colour key or chromalin but are not as colour-correct.
Digital printing is actually closer to colour photocopying than to printing. In digital printing, the prints are made directly from a computer file without film or plates. This method is ideal for lower-quantity and customized needs but can only print CMYK images and files. Like photocopying however, the price-per-piece tends to be the same. You'll probably pay the same price per piece for 50 or 5,000. When you need higher quantities of full-colour printing, it makes sense to figure out which method is best for your needs. The answer to your particular situation may surprise you.
When you start a project that will be printed, it's best to find a few printers to discuss the project with. You can ask associates, a business group or your designer for recommendations. It's a good idea to visit and meet the printer to get a feel for who you'll be dealing with.
You'll need to tell the printer a few things about your project but you should also be prepared to ask a few questions like:
- How long have you been in business?
- What are your hours of operation? Do you print at night or on weekends?
- How many presses do you have and what are the colour capabilities of each?
- What software and materials can you accept?
- What linescreen do you use?
- Is there a specific kind of project that you specialize in?
- Can I see some samples of your print work?
- May I contact some of your clients for their feedback?
- What kind of proofs can I expect to see before my project is printed?
- How much time will I have to review the proofs?
- . If I am not satisfied with the quality of the printing, will you reprint the job at your cost?
- What method of payment will you accept?
Before you start a project, I'd recommend talking to a few printers to ask for printing quotes. It's best to talk to them before your job is designed. This way, you can figure out what specifications the printer recommends and what kind of job is in your budget. It's counterproductive and expensive to have a full-colour piece designed only to find out that your budget will allow for a two spot-colour printing job. It's also a good idea to get several time and money quotes, in writing, as these details can vary widely from printer to printer. A project that's two weeks late and costs hundreds of dollars more than you expected is not a situation you want.
When you talk to a perspective printer, be prepared to tell them the following information:
- The name of your project.
- The dimensions and number of pages of the project.
- The number of colours, process or spot, for the project.
- The quantity of finished pieces that you'll want.
- The colour, feel and weight of the paper that you want the project printed on.
- The materials that you will be supplying to the printer (computer files or pasted-up documents).
- When you need the project completed or delivered.
Your printer will be able to offers some recommendations in terms of paper, matching colours, software acceptability, etc. You can ask if there are any ways that you can save a few dollars by altering the page size of the finished piece, using different colours, etc...
To ensure that you get quotes that you can easily compare, make sure that you give each of the perspective printers the exact same specifications to bid on.
This information, combined with your knowledge of the printer, should ensure that your project looks great and is delivered both on budget and on time.
If your budget for a printed project is low, there are several things you can do to keep costs to a minimum. Here's a few tricks to keep your printing project on budget.
- Ask your printer for paper size recommendations to minimize paper waste.
- A one colour job is the cheapest to print. However, that one colour doesn't have to be black. If you consider using another dark colour, the text will be dark enough to read and a designer can use the colour, in varying tints, to liven up the document. If done well, one can get the feel of two colours while paying for only one.
- Fewer colours cost less Not only will you save on ink but you'll also save on film and plate expenses as well. If your chosen printer runs mostly CMYK jobs, it may be cheaper to run a full-colour job than a two or three colour one because that entails cleaning the press and mixing custom inks.
- On a one or two-colour job, consider having it printed on a coloured stock to add additional interest.
- Jobs with images or colours that run off the edge of the page (called "bleeds") will typically cost a bit more than those that don't.
- Ask the printer if they have any extra paper left over from another clients' job which might cost you less.
- Ask what the best and most cost-efficient way is to supply your project to the printer.
- Look for discount printers that print several small jobs at the same time. You won't have the same amount of colour or paper stock control but you can frequently get full-colour printing at a very reasonable rate.
- Don't make changes to your document once you've supplied it to the printer.
If you want to save a lot of time and money when you work with a printer, it's best to make sure you have a designer that has a good understanding of how spreads, signatures and imposition work.
There are basically two kinds of spreads in the printing world; reader spreads and printer spreads. When you open a magazine that's saddle-stitched (stapled in the center), page two is across from page three. You are looking at a reader's spread; it's what the reader sees. The two pages are not part of the same piece of paper but they appear across from one another.
If you take the staples out of the magazine, you'll see that page two is actually connected to another page at the back of the magazine. This is called a printer spread; it's what a printer prints. When the magazine was printed, these pages were printed next to each other, folded and then stapled so that you received a magazine bound in the center.
If a designer provides a printer with reader spreads, the printer will have to manually change the page order to printer spreads. This will cost time and money and will increase the chances of having a problem with the project. Designers should always provide printer's spreads to a printer. Keep in mind that, for saddle-stitched jobs, your pages should be in increments of four. If not, you may end up with some blank pages in the back of your project.
A signature refers to the group of pages that are printed on the same sheet of paper. The paper is then cut and trimmed down to the finished page size. The number of pages on a signature depends on your page size and the size of the printer's sheet or roll of paper.
Imposition refers to the placement and direction of pages in a signature. Some pages may appear upside down or backwards but, once it's folded and cut, the pages will be in their proper position and sequence. A printer would set up a signature's imposition.
How can a printer print a grayscale photograph with black ink? A mystery of the universe? No, but I do think whoever came up with this one should've gotten a big bonus in their paychecks. Think how different our world would be if we couldn't print photographs in our books and magazines! Okay, on to the explanation...
A printing press is able to produce only clear, defined images in the colour of the ink on the press. To reproduce a wide range of continuous and intermediate tones of gray in a black and white photograph, the photograph must first be converted to an image that conforms to this limitation. This conversion is done by the use of halftone screens.
By shooting a photograph through a screen of dots with a stat camera, the image is converted to rows of tiny black dots. The size and intensity of these dots is relevant to the darkness of the gray areas. These days, photographs are usually scanned into a computer system and output with the halftone screens. The photo can be printed at whatever screen frequency you desire.
The resulting dots create an optical illusion. Because the dots are so small and are of varying proximity to each other, our eyes are fooled into seeing shades of gray when there's only black dots. Halftone screens are measured by the number of lines of dots in an inch of the screen.
The halftone screen frequency, or linescreen, that one uses is dependent on the capabilities of the press and the paper that will be used to print a project. Presses that print newspapers are only capable of handling a low linescreen like 85 lines per inch (lpi). Quality magazines use linescreens of 150lpi and up. The finer the linescreen (the more dots per inch), the better the reproduction quality and detail you'll see in the image.
However, a word of caution: a linescreen that is too high for a paper or press' capabilities, will not look very good at all. The dot pattern will start to fill in and the images will look blotchy and muddy. Ask your printer what linescreen they prefer. You will need to know this before printing film can be ordered. You will also need to know this before images can be scanned so you know what resolution is required.
Duotones are two-colour halftone image reproductions. Usually, a duotone will be made up of black and one other colour, though it doesn't necessarily have to be. A duotone should be created so that the two colours are used at different intensities. This can create an image with subtle colouring that does not overpower or muddy the image's clarity. If done correctly, the result is a photograph with greater depth of colour than a plain grayscale photo.
A duograph, or a "fake duotone," is created by printing a one-colour halftone over a tint or solid colour. The effect is not nearly as effective and one loses a lot of the photo sharpness. It looks pretty crappy all around.
Tritones and a quadtones are halftones that use three and four colours respectively. Personally, I can't say that I've ever seen one of these that were all that impressive. If you have four colours, I'd suggest going with CMYK inks and have the option of using full colour photos!
Web presses (not related to the Internet) are really the way to go if one needs really large quantites of magazines, newspapers or catalogs printed (we're talking many thousands and thousands here). All of the national publications that you see on a newstand are printed this way. A Web offset press can run much, much faster than ordinary sheet-fed offset presses while still delivering excellent quality. Typically, web presses can handle several colours of ink at the same time. Some web presses can print eight or more colours on the same run. frequently these extra colour capabilities are used for varnishes.
In addition, many web presses also have a lot of finishing equipment attatched to them so that your folding, binding, perforating and cutting (everything but your grocery shopping) are done all on the same machine at a fast speed. Serious pieces of equipment for seriously large projects. Discuss with your printer if using a web press would be an advantage.
The standard weight of a paper is defined by the weight of 500 standard-sized sheets (such as 17.5" x 22") in pounds. Some different paper weight categories are:
Bond Bond paper is what you would find around an office being used for a copy machine or for letterhead. It's typically an uncoated paper. 20lb. bond paper is the standard for copy machines today while 24lb. paper is usually used for letterhead.
Book Book paper can be either coated or uncoated with 30é100lb. weights for 500 standard-sized sheets. Book paper is typically used for lesser grade projects like books, magazines and posters.
Text Text is a higher-quality paper than book paper and can be found in better-quality books, magazines and annual reports. A common weight for this kind of paper is 70é80lb.
Cover Cover stock is the heaviest paper and is typically used for postcards, business cards, paperback book covers, etc. Typical cover stock paper weights are 60é100lb.
Sticker Sticker stock is intended to be printed on only one side. The reverse side is sticky and is covered by a peel-away paper. This stock can be either coated or uncoated.
Because it costs more to produce and transport, the heavier weights of paper usually cost more than the lighter ones. They also cost more to mail which can be an important thing to consider.
There's a whole lot of different ways to bind a multi-paged project. Some of these methods can be applied by affordable equipment while other methods are best left to bindery professionals found in a bindery. Here's a bunch of professional and office methods for holding pages together.
Saddle-stitch binding This is a very common binding method and involves using one or more staples on the fold of a signature. Magazines, like TIME for example, are the most common example of this kind of binding. Where does the saddle-stitch name come from? Well, it has to do with the way the staples are applied. The signatures are fanned open with the inside pages face down on the binder, like a horse's saddle, as they are stapled. Hence the name.
Side-stitch binding This method involves putting all the signatures together, much in the same way as saddle stitching, and staples the pages on the side rather than the fold. Not quite as nice as saddle stitching binding.
Perfect binding Many annual reports use this method and it's ideal for holding 50+ pages together. This binding method takes all of a project's signatures together and the spine edge is ground to a perfectly flat edge. The cover is then glued to the outside edge of the signatures. One word of caution when using perfect binding: one will lose the visibility of part of the inside pages because of the binding area. A designer should take this into consideration and should allow a bit of an extra gutter for this. You'd be surprised at how often I see this goof.
Case binding This is the method that one sees most often on hardcover books. Signatures are sewn together, glued to a gauze strip and then glued to end papers which are attached to the hard covers. It's quite a process!
Plastic comb binding Ideal for business reports and the like, this method uses plastic teeth that insert into a series of tiny holes made in a stack of pages. Comb binding machines are pretty inexpensive and the spines can be removed and reattached as needed.
Three-ring binding C'mon, you remember these from high school! Watch your fingers!
Though the design industry has changed dramatically with the advent of the computer age, picas and points are here to stay. Could you really envision everyone switching over how they describe font sizes, rule widths or leading? Not likely at this point.
Actually, once you get familiar with them, they're not very hard to understand at all. Just as there are 12 inches in a foot, there are 12 points in a pica. That's easy enough to remember. So, how big is a pica? Well, there's actually 6 picas in an inch. It's based on multiples of six, just like our own standard measuring. So, if there's 12 points in a pica and 6 picas in an inch, how many points in an inch? Let's see, 12 x 6 =72. There's 72 points in an inch.
Though pretty useless in everyday life, there are times when this information can be quite valuable. If a designer wants to divide an 11" sheet into three equal sections, how big would each section be? I'm sure you're not the only one reaching for a calculator. But, if I told you there were 66 picas in 11 inches, I'm sure you could tell me that each section would measure 22 picas. Pretty simple, huh?
Varnishes, though they are actually part of the printing process, come to mind as more of a part of the finishing process. Varnishes are an extra coating put on all or certain areas of a printed piece to give it a more slick or finished appearance.
Varnish is actually a liquid shellac or plastic that is used like an ink on the printing press. It can be loaded just like an ink colour and applied after all of the ink has been printed on the paper. A varnish can be clear or tinted and can give either a glossy or a dull-finish. Designers use varnishes in a variety of ways and create a whole slew of different effects.
One thing to keep in mind: varnishes are best used on coated stocks. Uncoated stocks tend to soak the varnish into the paper so it's virtually invisible. I once saw five coats of varnish applied to an uncoated stock and couldn't tell that any had been applied. Keep in mind that designers and printers should be sure that the combination of the coated stock and the varnish will not create a too much of a reflection. Your readers may not appreciate having to wear sunglasses just to read you piece.
CMYK refers to the printing inks used in four-colour process printing. Cyan, Magenta, Yellow and Black are the colours used to produce full-colour photographs and designs. (An approximate representation of these colours is below.) These colours can be combined and printed to emulate a wide number of other colours. If you look carefully at a printed colour photograph in any magazine or book, you'll see that it's made up of rows of tiny dots called a halftone screen. The dots work together, at different angles, to fool your eye into seeing a full spectrum of colours.
For a graphics file to be printed in CMYK, it must be converted or created in that colour mode. When film is produced, a different sheet of film is created for each colour. For the computer to tell the machine that produces the film, an imagesetter, what to put on each sheet of film, the computer image must be in CMYK format. Colours in a page layout program must also be specified in percentages of the four coloured inks.
So, why do we refer to these four ink colours as CMYK and not CMYB? Well, quite simply, it's so that no one will be confused into thinking that the last colour is Blue rather than Black.
Moiré (pronounced "more-ray") pattern is sometimes seen in printed materials. Moiré patterns come about when two halftone screen patterns come into conflict é something that both designers and printers want to avoid. There's a few common ways for this to happen.
A common method of causing a moiré screen is by scanning an image that has been previously printed with a halftone screen. A typical example would be a printed photograph in a book or magazine. (One can tell if an image contains a screen by looking very closely with a loop or a magnifying glass.) If a screened image is scanned and then printed, there's a good chance a moiré pattern will appear on the image. The original screen in the image conflicts with the screen that the printer or imagesetter is using to render the image and creates a nasty optical pattern. A designer can sometimes get around this issue by blurring a scanned image with an image-editing program. Image clarity can be severely sacrificed with this method but it can be better than a moiré pattern.
Moirés can also be created through incorrect screen angle settings in colour printing. Usually, page-layout programs, which are used to import photos into page layouts, set default angles which will print correctly. Occasionally, a printer will have their own preference of screen angles and a moiré can occur.
The standard process printing screen angles are Cyan = 105é, Magenta = 75é, Yellow = 90é and Black = 45é. The important thing to remember is that each colour must have a distinctive screen angle of its own. These angles are unique and will help avoid an unpleasant moiré pattern.
If a designer needs to match a particular colour (a logo colour perhaps) in a printed piece or has a limited budget, then spot colour is something to consider. Spot colours can also be used alongside process (CMYK) colours for greater flexibility.
To ensure that a printer uses exactly the colour that a designer intends, colour systems were developed. The most common of the spot colour standards is the Pantone Matching System or, PMS as it is more commonly known. All of the modern image-editing, vector-drawing and page-layout programs come with a full library of thousands of Pantone colours as part of the program.
In addition, designers will want to have a set of swatch books that show printed examples of the colours and their codes. Swatches are a more reliable method of matching or choosing colours than doing so on-screen. This is because monitors are illuminated by light behind them which makes colours seem brighter on-screen than they are when printed on paper. Also, colours on a monitor are created with red, green and blue light (RGB) rather than mixed ink pigments.
Though some may view spot colour printing as being much more limited than CMYK printing, there are many interesting possibilities.
- Two or more spot colours can be mixed to create interesting colours and effects.
- Spot colours can be combined to create duotones, tritones and quadtones that can be very effective and can add some visual interest to otherwise grayscale images.
Unfortunately, it's difficult to proof spot colour jobs. Most proofing systems use CMYK-based technology. Some laminated proofs, which work by attaching coloured sheets of clear acetate, have some spot colours available but these are often expensive.
There are many factors to consider when choosing what kind of paper a project should be printed on. Many designers don't give this area much thought but should as it ca greatly contribute to the overall look of a printed piece. Things that should be taken into consideration when choosing a paper are:
Opacity Opacity refers to how much you can see through the paper. If printing a magazine or book with a lot of text, one will want a good amount of opacity in the paper that is chosen. Otherwise, the reader may be bothered by printed material showing through from the other side of the page.
Thickness This refers to how thick a page is. Sometimes, a paper that doesn't weigh much can still very thick. Books and magazines printed on thick pages appear to have more pages than they do. Thicker papers can cost more to mail but may be necessary as in the case of postcards.
Brightness Brightness refers to how much light is reflected off the paper. Coated stocks reflect much more light than uncoated stocks do. Though some brightness is preferable, be sure to get a paper that will not reflect too much and prevent the reader from seeing what's on the page.
Strength This refers to how durable and strong a paper is. Paper bags need to be strong to be able to hold up under the stress of holding heavy items while other projects don't require as much.
Paper is often the most expensive part of a printing job and should be chosen accordingly. A local paper supplier or your printer should be able to supply you and your designer with books and books of paper samples to choose from.