Image
05-31-2005, 01:07 AM
Hi. I made this as kind of a tell all that everyone can review befor eposting questions about designing for print. It will be in depth, covering all the basics and answering a lot of the questions I see popping up all the time.
Okay, here we go.
Types of printing
There are several kinds of printing, but they mostly break down into two categories: Digital and Offset. Digital Printing works just like your printer at home, and is ideal for short run (<500) full color jobs because there is a lot of labor involved in setting up offset printing (see below), too much trouble to just run a few flyers. Digital prints runs either single sheets (like your printer), or small parent sheets (like Kinkos). Parent sheets are larger sheets of paper that several copies of the same job can be printed on and then cut, like printing two of the same 8.5 x 11 flyer on an 11 x 17 sheet and cutting it in half. Because of it's single sheet-single job format, it's productivity is lower than gangrun offset printing(below) and the cost per sheet is higher, but the setup labor and cost is sufficiently lower than offset.
Offset printing refers to the process of spreading ink on a metal plate with etched images, then transferring the ink to an intermediary surface such as a rubber blanket, and finally applying the ink to paper by pressing the paper against the intermediary surface. This has to be done 4 times on a full color job. Once for the C, once for the M, once for the Y, and once for the K. It seems like more work, but can be done to enormus parent sheets (like 4' x 8') extremely quickly. This is advantageous because if you have many jobs of the same quantity all from different clients, you can run them all together on one huge parent sheet. This process is commonly called a gangrun.
Think of it this way. Digital printing is like the printer on your desk. The art goes right from the computer to the printer. Offset printing is like a big stamp. It requires engraving four huge pieces of metal each with a negative of the artwork. You can print digital if you don't want to make four metal plates and four rubber blankets and use a million dollar machine to run 200 posters for your band's show. You can print offset if you want to print 100 pages per second on your 5000 page business card run. If you printed 5,000 sheets digital, it would be like printing out 5,000 color photos from your printer at home. It would take days. Offset printing large runs takes hours. Digital printing has no cost to set up, but is expansive to run, offset printing is expensive to set up, but costs nearly nothing to run.
Vector and Raster
Aforementioned are the different programs that make raster and vector artwork. But what's the difference?
Basically, Vector art can be scaled to any size without distortion, raster art looks pixelated when made too large.
But why?
When you draw something in vector, the shape isn't actually there. A line of code and an equation make the shape. When you draw a circle 100px in diameter in vector it's actually a mathmatical formula saying a circle, black, at 100px. When you scale it up, it doesn't scale the shape, it just increases the diameter measure in the formular proprotional to the amount you scaled the "circle" up (calculated to the .00001%).
When drawing in raster, you create a definite shape, made up of a definite amount of pixels. When you scale the shape larger, it scales all the pixels larger as well. If you scale it enough, the pixels become large enough to become independently visible, and that, my friends, is pixellation.
Raster images are anti-aliased (discussed below), and therefore a black raster circle is actually made up of hundreds of shades of gray. If you're trying to print a raster circle, and you only have one black ink canister in your 2 color press (also described below), the printer won't knnow what to do with all of the other grays, because you don't have a canister of ink for every single gray in the circle. In vector, the shape goes to the printer as only a smooth black circle.
Resolution
When designing for print, you must start by designating your resolution. What is resolution? Resolution refers to how much color and shape information is in every square inch of the artwork. Information in every inch can be drawn as tiny dots, tiny lines, tiny points, squares, samples, whatever (ppi, dpi, spi, lpi, etc). So which is which? The only difference between the terms are the devices being used. Scanners, monitors, and other light-based optical devices generally use PPI or spi. Output devices (printers etc.) use dpi or lpi. Lpi is lines per inch from the days of dotjet printing (tiny pinholes throughout the paper. You remember, your dad's office printer when you were a little boy that made that terrible screech when it printed), and is typically an anachronistic technology.
In Vector programs like Illustrator, Freehand, or Draw, setting resolution is not necessary. In raster programs like Photoshop, Fireworks, Painter, artwork should always be at least 300 DPI. If your raster art for print meets this requirement, pixels will never show. When running a one, two, or three color job (jobs printed with specific pantone inks, and not a million+ color mixture of CMYK), the artwork must either be Vector, or at least 1200 DPI.
Color
Full color jobs must be set up CMYK. Two color pantone ink jobs should be set up in CMYK file format, but set one of your colors as 100% C, and another one of your colors as 100%M. That way, the prepress professional at the Print Shop can just plate everything that's C & everything that's M, but put whatever ink you specify in the press when he runs the job.
Black
In four color printing, black should always be mixed as 60C, 60M, 60Y, and 100k. If you just use 100k in full color printing you get a flat, kind of faded black. The former mixture produces a thick, dark, rich, shiny black.
In two color vector offset printing, 100k is fine.
cutting margins and bleed
Bleed refers to whether or not the ink runs to the edge of the paper. Every printer has little grippers that feed the paper through. The portion of the paper that they grab on to obviously can't be printed on, so to make the ink run all the way to the end (for example, on a full color 11x17 poster) you load paper that is larger than the art (like 12x18, in this case), and cut of the white area where the gripper fed the paper. The cutting process isn't always accurate, so to make sure the knife cuts just a little of the printing off (to make the printed area run off the page, so to speak), it's a good idea to set up your art to be 1/8'' larger all around than the final size of the document, also called finished size and keep any mission critical text and graphics well AWAY from that area.
EXAMPLE - When Sending a 3.5x2 business card to print, supply a file that is 3.625 x 2.125, allowing an eigth inch all the way around for cutting.
Large format printing
When printing to vinyl, a banner, or any other form of very large media (which is printed out of an extremely large exact replica of the printer at your desk, mostly), avoid any huge cavernous margins of black. It can be done, and often is, but is extremely expensive and difficult to print it. Oftentimes a printer will throw away three or four foul ups before actually getting your banner/sticker/bus stop poster/etc right.
File types and file sizes
For full color printing:
a Flattened, not compressed TIFF works the best; however, when you're tying to optimize the file size, a JPEG, set to highest quality works just fine, too. PDFs are generally not recommended, and raster EPS's are exnormus and troublesome for a printer to use.
For two color and pantone printing:
.PDF's are great. .EPS files are ideal. In vector printing, MAKE SURE ABSOLUTELY ALL OF YOUR FONTS ARE OUTLINED!
general rule of thumb
Never give a printer a single file more than 100MB. They are people, too. They have hard drives, too. Most of them have millions of dollars worth of machinery in their network, a workflow you would not believe, and very, very, very little patience. Since most of them are still using PC (sorry! couldn't resist!), large and complex files get handled more slowly. Be nice and give them smaller files that the computer can handle.
Aliasing and Anti-Aliasing
Aliasing refers to the fact that each character, shape, and image we see on a computer screen is actually made up of a bunch of tiny little squares called pixels. Because of this, a monitor can never, ever, display a truly smooth curve. While monitors today are getting extremely high tech with millions of pixels, and shapes are displaying as smoother and smoother, zooming in on the object shows it's jagged stairstep formation.
Anti-aliasing a shape means varying the levels of opacity in each pixel of a shape as you get closer and closer to the edge. This creates an optical illusion that makes a shape appear smooth onscreen. Here is an example.
http://www.widearea.co.uk/designer/images/unalias.gif
Zoomed.
http://www.widearea.co.uk/designer/images/unaliasbig.gif
Here is the same letter antialiased.
http://www.widearea.co.uk/designer/images/alias.gif
And actually looks like this:
http://www.widearea.co.uk/designer/images/aliasbig.gif
[i]What does this have to do with printing?[/b]
Anti aliasing is great for on screen presentations. However, paper does not have pixels, so do not anti-alias high-resolution fonts or shapes that are to go to print. Printing anti-alisaed images will do just that, print the anti-aliasing blur, and will make all of your text blurry and illegible.
Okay, here we go.
Types of printing
There are several kinds of printing, but they mostly break down into two categories: Digital and Offset. Digital Printing works just like your printer at home, and is ideal for short run (<500) full color jobs because there is a lot of labor involved in setting up offset printing (see below), too much trouble to just run a few flyers. Digital prints runs either single sheets (like your printer), or small parent sheets (like Kinkos). Parent sheets are larger sheets of paper that several copies of the same job can be printed on and then cut, like printing two of the same 8.5 x 11 flyer on an 11 x 17 sheet and cutting it in half. Because of it's single sheet-single job format, it's productivity is lower than gangrun offset printing(below) and the cost per sheet is higher, but the setup labor and cost is sufficiently lower than offset.
Offset printing refers to the process of spreading ink on a metal plate with etched images, then transferring the ink to an intermediary surface such as a rubber blanket, and finally applying the ink to paper by pressing the paper against the intermediary surface. This has to be done 4 times on a full color job. Once for the C, once for the M, once for the Y, and once for the K. It seems like more work, but can be done to enormus parent sheets (like 4' x 8') extremely quickly. This is advantageous because if you have many jobs of the same quantity all from different clients, you can run them all together on one huge parent sheet. This process is commonly called a gangrun.
Think of it this way. Digital printing is like the printer on your desk. The art goes right from the computer to the printer. Offset printing is like a big stamp. It requires engraving four huge pieces of metal each with a negative of the artwork. You can print digital if you don't want to make four metal plates and four rubber blankets and use a million dollar machine to run 200 posters for your band's show. You can print offset if you want to print 100 pages per second on your 5000 page business card run. If you printed 5,000 sheets digital, it would be like printing out 5,000 color photos from your printer at home. It would take days. Offset printing large runs takes hours. Digital printing has no cost to set up, but is expansive to run, offset printing is expensive to set up, but costs nearly nothing to run.
Vector and Raster
Aforementioned are the different programs that make raster and vector artwork. But what's the difference?
Basically, Vector art can be scaled to any size without distortion, raster art looks pixelated when made too large.
But why?
When you draw something in vector, the shape isn't actually there. A line of code and an equation make the shape. When you draw a circle 100px in diameter in vector it's actually a mathmatical formula saying a circle, black, at 100px. When you scale it up, it doesn't scale the shape, it just increases the diameter measure in the formular proprotional to the amount you scaled the "circle" up (calculated to the .00001%).
When drawing in raster, you create a definite shape, made up of a definite amount of pixels. When you scale the shape larger, it scales all the pixels larger as well. If you scale it enough, the pixels become large enough to become independently visible, and that, my friends, is pixellation.
Raster images are anti-aliased (discussed below), and therefore a black raster circle is actually made up of hundreds of shades of gray. If you're trying to print a raster circle, and you only have one black ink canister in your 2 color press (also described below), the printer won't knnow what to do with all of the other grays, because you don't have a canister of ink for every single gray in the circle. In vector, the shape goes to the printer as only a smooth black circle.
Resolution
When designing for print, you must start by designating your resolution. What is resolution? Resolution refers to how much color and shape information is in every square inch of the artwork. Information in every inch can be drawn as tiny dots, tiny lines, tiny points, squares, samples, whatever (ppi, dpi, spi, lpi, etc). So which is which? The only difference between the terms are the devices being used. Scanners, monitors, and other light-based optical devices generally use PPI or spi. Output devices (printers etc.) use dpi or lpi. Lpi is lines per inch from the days of dotjet printing (tiny pinholes throughout the paper. You remember, your dad's office printer when you were a little boy that made that terrible screech when it printed), and is typically an anachronistic technology.
In Vector programs like Illustrator, Freehand, or Draw, setting resolution is not necessary. In raster programs like Photoshop, Fireworks, Painter, artwork should always be at least 300 DPI. If your raster art for print meets this requirement, pixels will never show. When running a one, two, or three color job (jobs printed with specific pantone inks, and not a million+ color mixture of CMYK), the artwork must either be Vector, or at least 1200 DPI.
Color
Full color jobs must be set up CMYK. Two color pantone ink jobs should be set up in CMYK file format, but set one of your colors as 100% C, and another one of your colors as 100%M. That way, the prepress professional at the Print Shop can just plate everything that's C & everything that's M, but put whatever ink you specify in the press when he runs the job.
Black
In four color printing, black should always be mixed as 60C, 60M, 60Y, and 100k. If you just use 100k in full color printing you get a flat, kind of faded black. The former mixture produces a thick, dark, rich, shiny black.
In two color vector offset printing, 100k is fine.
cutting margins and bleed
Bleed refers to whether or not the ink runs to the edge of the paper. Every printer has little grippers that feed the paper through. The portion of the paper that they grab on to obviously can't be printed on, so to make the ink run all the way to the end (for example, on a full color 11x17 poster) you load paper that is larger than the art (like 12x18, in this case), and cut of the white area where the gripper fed the paper. The cutting process isn't always accurate, so to make sure the knife cuts just a little of the printing off (to make the printed area run off the page, so to speak), it's a good idea to set up your art to be 1/8'' larger all around than the final size of the document, also called finished size and keep any mission critical text and graphics well AWAY from that area.
EXAMPLE - When Sending a 3.5x2 business card to print, supply a file that is 3.625 x 2.125, allowing an eigth inch all the way around for cutting.
Large format printing
When printing to vinyl, a banner, or any other form of very large media (which is printed out of an extremely large exact replica of the printer at your desk, mostly), avoid any huge cavernous margins of black. It can be done, and often is, but is extremely expensive and difficult to print it. Oftentimes a printer will throw away three or four foul ups before actually getting your banner/sticker/bus stop poster/etc right.
File types and file sizes
For full color printing:
a Flattened, not compressed TIFF works the best; however, when you're tying to optimize the file size, a JPEG, set to highest quality works just fine, too. PDFs are generally not recommended, and raster EPS's are exnormus and troublesome for a printer to use.
For two color and pantone printing:
.PDF's are great. .EPS files are ideal. In vector printing, MAKE SURE ABSOLUTELY ALL OF YOUR FONTS ARE OUTLINED!
general rule of thumb
Never give a printer a single file more than 100MB. They are people, too. They have hard drives, too. Most of them have millions of dollars worth of machinery in their network, a workflow you would not believe, and very, very, very little patience. Since most of them are still using PC (sorry! couldn't resist!), large and complex files get handled more slowly. Be nice and give them smaller files that the computer can handle.
Aliasing and Anti-Aliasing
Aliasing refers to the fact that each character, shape, and image we see on a computer screen is actually made up of a bunch of tiny little squares called pixels. Because of this, a monitor can never, ever, display a truly smooth curve. While monitors today are getting extremely high tech with millions of pixels, and shapes are displaying as smoother and smoother, zooming in on the object shows it's jagged stairstep formation.
Anti-aliasing a shape means varying the levels of opacity in each pixel of a shape as you get closer and closer to the edge. This creates an optical illusion that makes a shape appear smooth onscreen. Here is an example.
http://www.widearea.co.uk/designer/images/unalias.gif
Zoomed.
http://www.widearea.co.uk/designer/images/unaliasbig.gif
Here is the same letter antialiased.
http://www.widearea.co.uk/designer/images/alias.gif
And actually looks like this:
http://www.widearea.co.uk/designer/images/aliasbig.gif
[i]What does this have to do with printing?[/b]
Anti aliasing is great for on screen presentations. However, paper does not have pixels, so do not anti-alias high-resolution fonts or shapes that are to go to print. Printing anti-alisaed images will do just that, print the anti-aliasing blur, and will make all of your text blurry and illegible.