You Say You Want a Resolution?

By: Jim Babbage

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Set for printing

It's inevitable, really; there you are, happily designing graphics for a client's web site, when all of a sudden, the client calls and says. "Oh yeah, I need that stuff to go into my newspaper ad, too."

This is a defining moment for you, as a graphics professional. Do you:

  1. Say, "Sure, no problem!" and continue to work away happily on your 72 PPI bitmap image, figuring you'll just change things later.
  2. Stop what you're doing and ask, "What size will the ad be? Color or Black and white? What's the line screen being used for printing?" At which point, the client gives you the phone number for the newspaper's ad department, and hurriedly gets off the phone.
  3. Stare apprehensively at that Photoshop box on your shelf (the soundtrack from "Psycho" or "Jaws" running in your brain).
  4. Babble incoherently, thinking you're way out of your league, and hit the CMX forums in hopes someone knows what to do.

Welcome to the world of print graphics. If you answered 1, 3 or 4, then this article will be helpful. If you answered "2", you may know more about commercial printing than I do.

Fireworks was never designed to be a print graphics application - which is fine by me; I'd rather have it do one thing, and do it well. But that doesn't change the fact that sooner or later, someone is going to ask you to create graphics that can be used in print.

Here's what this article will do:

  • Clarify the different resolution measurements (PPI, DPI, etc.)
  • Define the different types of resolution
  • Where to start in Fireworks
  • Where to go from Fireworks

Some on the information here may be review for some of you. But I'm of the belief that it never hurts to read something twice (Especially an IKEA instruction booklet).

Resolution Measurements and Terms

Pixels per Inch (PPI): how many pixels would be inside a linear inch when the file is printed. This measurement has nothing to do with your monitor or the web, and everything to do with printing. In terms of an image file, the higher the amount of PPI, the larger the file size will be or the smaller the image dimensions will be when the file is printed. Image Resolution and the dimensions of the image determine the file size of the document.

For example, an image that is to be printed at a size of 4x6 inches with a current resolution of 72 PPI would be 365 K and would have a pixel dimensions (Image resolution) of 288 px by 432 px. The printed image would not be good quality.

If we maintained the same pixel dimensions, but changed the PPI to 300, the image would print out at a size of 0.96 inches by 1.44 inches, but the print quality would be great (if you could see it). If we resampled the image to print at 4x6 with a resolution of 300ppi, we would end up with poor image quality. Basically, there is - or needs to be - more data (more pixels) to print a 4x6 inch, 300 ppi image. This data needs to exist at the time of capture. Scaling or resampling a lower resolution image would NOT result in better quality.

An image that is to be printed at a size of 4x6 inches at 300ppi is over 6 MB and would have an image resolution of 1200 px x 1800 px. This image would be of much better quality when printed, assuming that the image was captured or scanned at this resolution.

Dots per Inch (DPI): often (and incorrectly) interchanged with PPI, DPI is an ink-on-paper printing term, referring to the number of halftone dots in one inch. This is referred to as Printer Resolution. A standard laser printer is anywhere from 300 - 600 DPI

If your work is going to print, you need to know the final print dimensions, DPI and/or Linescreen BEFORE you start designing. Up-sampling a screen-based image to the dimensions and resolution needed for print is something you do NOT want to do. The print quality will be poor.

Lines per Inch (LPI): LPI is the number of halftone lines per inch in a printed document. Also known as Screen Frequency, Screen Ruling or Press Resolution. As a general rule, you want to have 1.5 - 2 x as much image resolution (PPI) than LPI. So an image to be printed using a 133 Line Screen (LPI) would need to be 266 PPI, at the desired output dimensions (4x6 inches for example) to maintain good reproduction quality. Common line screens run from about 80 LPI to 200 LPI. Black and white newsprint is typically 85 LPI. A color magazine ad is usually 133 LPI.

Halftone Screen: the pattern of dots used to recreate an image in and ink-on-paper medium. It's a combination of DPI and LPI. Unlike photographic paper, a printing press is really only capable of putting solid ink on paper, rather than a continuous tone image. A halftone screen lets the ink be printed as small dots on paper, which gives us the illusion of a real photograph. As a quick example, grab a nearby magazine, and inspect any printed photo with a magnifying glass. See all those multicolored dots? That's the halftone screen!

Traditionally, to print a photograph in a newspaper, you had to re-photograph the image using a halftone screen and a REALLY big camera, called a Stat Camera. Today, halftone screens can be set digitally in the print set-up of programs like Photoshop and Freehand.

Resolution Defined

Image Resolution

The number of pixels that make up the image. For example, an image on your web site might be 400 pixels wide, by 200 pixels high. The total number of pixels (resolution) of this image is 400 px x 200 px, or 80,000 pixels. Those dimensions do not change unless you resample the image to include more (up-sample) or less (down-sample) pixels.

Monitor Resolution

A monitor displays an image using pixels (short for picture elements). This is the smallest unit of display for a monitor. Digital dots - as it were.

Don't confuse monitor resolution with video card resolution. They are different, and this is usually one of the first stumbling blocks web graphics designers hit.

Video Card Resolution

This is the way you adjust how much desktop real estate you have to work with. A lot of people think this is monitor resolution, but it isn't. Common settings are 800x600, 1024x768 and 1280x1024. The higher the numbers, the more desktop space you seem to have. It does NOT change the monitor resolution. That value is fixed. This is why - when you change video card resolution, everything on your screen appears to change in size; the pixels just get bigger or smaller.

Output Resolution

This resolution varies depending on the output device (monitor, laser printer, image setter, printing press).

Scan Resolution

The size of your final image, compared with its original size and the output resolution are the factors to consider here. You need to know - up front - how large the image will be reproduced, and at what line screen, in order to get make a suitable scan. Large dimension image reproduction and higher line screen settings mean that more data must be gathered at the time of the scan. This will result in a larger file size, as well.

Some Tips

Fireworks may be your graphic application of choice. It may be the one you are the most comfortable with, and feel the most creative while using. Be that as it may, Fireworks is not designed to be used for artwork destined for the print world, for at least three reasons.

Fireworks does not understand CMYK. The color mode used by Fireworks is RGB only. It cannot fathom the process colors used for print Cyan, Magenta, Yellow and - most importantly - Black (The "K" in CMYK).

Fireworks does not understand color profiles. Color profiles are used by printers and service bureaus - and software like Photoshop - to maintain color consistency across a wide array of display and output mediums. As far as Fireworks is concerned, there is really only one output medium: a computer monitor.

Fireworks does not handle large files efficiently. This was especially true of older versions of Fireworks, but even MX and MX 04 don't handle large files as well as programs like Freehand or Photoshop.

Having said that, I designed my business cards in FW. The keyword here is designed. Once my design was complete, I moved the file over to a print graphic application for conversion to CMYK and any final tweaking that was needed.

So if you do want to start your print work in FW, because that's where you're comfortable, make sure you do the following:

  • Start with a NEW, blank document, set to a minimum of 300 PPI.
  • Ensure that the Canvas size is set in inches to the final reproduction size of your print work. This is especially important if you are using raster (bitmap) objects in your design. Vectors can easily be scaled with no quality loss; bitmaps can not.

For you web-heads (hey, that includes me, so smooth out them tail feathers) this means that an 8in x 10in image at 300 PPI would be 27.5 MEGABYTES, and would have pixel dimensions of 2400px x 3000px. A bit bigger than your average web page. Fireworks would grind to a screeching halt with a file this size.

New Document dialog box

Yep. Hefty.

Once your design is finished, save the PNG as a master file, and then open either Freehand or Photoshop (or another press-aware software package). If you have Acrobat 6.0 Pro, you can even save a color separated PDF file, by going to File > Print > Adobe PDF, and choosing Press Quality, from the Properties > Default Settings button.

 

I hope I haven't scared anyone away from moving their work to print. Preparation is the key. Even if you want to steer clear of the pre-press areas, making sure that your file is the right resolution and dimension will help to ensure you have a quality piece for printing.

For those of you who wish to learn more, below are some links that may be helpful.

  • My Design Primer is a great resource that explains printing terms and processes in a friendly manner
  • Wayne Fulton's website www.scantips.com is FULL of information, and I think will be a good resource for anyone interested in this area. This specific page: http://www.scantips.com/basics03.html talks a bit about LPI, but you may find that reading from the beginning will be a better idea.
  • Macromedia's Freehand Newsgroup
  • Techcolor Graphics Inc. A printing company with lots of helpful information.
  • The Freehand Source Ian Kelliegh's dedicated Freehand website.

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Keywords
Fireworks, Freehand, resolution, printing, PPI, DPI, halftone, pixels per inch