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Lines and pixels and dots, oh my!

Lines per inch, dots per inch, pixels per inch. Don’t those all mean the same thing? 

No. They don’t.

But you will find many examples of people saying dots per inch when they mean pixels per inch. I’ve probably done it myself. So how should you understand these three terms.

A pixel (from PICture ELement) is a tiny rectangular area of an image on your computer or phone screen. Now the real world is not divided into tiny rectangular elements. The real world is smoother than that. And the color of what you see in the real world may vary across that tiny area. But digital cameras and scanners average the real-world color across that area and arrive at a value that is some percentage of the maximum value of each of the primary colors red, green, and blue.

In modern computer systems, it’s convenient to divide data into eight-bit bytes. Eight binary bits are sufficient to express integers from 0 to 255. So if we give red a byte and green a byte and blue a byte (a common scheme, called 24-bit color), we can express 256 × 256 × 256 = 16,777,216 colors. (There are other schemes using more bytes that can express even more colors, but its arguable that the human eye’s ability to distinguish that many colors is already marginal. I digress. You may have noticed.)

So, again, the camera or scanner looks at a tiny region of the real world, averages the color, and comes up with a number that tells a display device how much voltage to energize the red, green, and blue components of a pixel with. And that’s fine for viewing an image on a screen.

But a printing press (or a laser printer or an inkjet printer) is not a screen, and it doesn’t divide the world into pixels. It uses dots.

Since the main purpose of printing is to render type, not images, I’ll start there. A dot either has ink (or toner) or it doesn’t. There are no levels of gray. There are only black and white (and cyan and white, magenta and white,and yellow and white, but we’ll get to those in a minute). On or off. Period.

Modern electronic printing technology typically uses a standard of 2,540 dots per inch (that’s 100 dots per millimeter if you’re wondering why the strange-looking number). So a character that is rendered at, say, 120 pixels per inch on your screen is rendered with dots that are one-twentieth the size of one of those screen pixels, so the curve of a letter C or O looks quite smooth, even if you look at it under moderate magnification. The same is true for a line on  a graph or an outline in a coloring book. The trick of anti-aliasing type on screen by having some pixels along the edges in various shades of gray instead of black is not needed (and not possible) on a printing press. Remember: ink or no ink. Black or white. Not 256 or even 16 levels of gray, not 16,777,216 colors.

So how does a black-and-white image (a picture, as opposed to type or a vector diagram) get printed? It begins with a halftone screen. This is an old analog technology that is modeled in modern image-processing software. In the analog world, a photo was placed on a copy board, and a photograph was taken of that photo with a piece of ruled film in front of the new film that was to be exposed. The rulings on the face of the film (the halftone screen) caused the light reflected from the image being photographed to diffract on the way through the thickness of the screen, producing halftone dots on the new film. Those dots were proportionate in area to the amount of light coming through that particular rectangle on the screen. So the dots varied in size. If you stood far enough away from the photo, it did not look like a rectangular array of oval dots; it looked like a continuous tone image, like the original. The spacing of the rulings on the screen determined the quality of the printed image. A newspaper might have used an 85-line screen, that is, a screen with 85 lines per inch. A weekly magazine or a history book might have used a 110- or 133-line screen (133 being considered good quality). A monthly might have used a 150-line screen. I think National Geographic used 175, and some art book printers used 200 lines per inch. At 150 lines per inch, a halftone dot occupies an area 16 printer dots square, any fraction of which can carry ink. But if you look at any halftone image, either black-and-white or color, under a magnifying glass, you can clearly see the halftone dots, in all their various combinations of sizes and grid orientations, that make up the image. (If you don’t want to squint through a magnifying glass, you can just look at paintings by Chuck Close, who exploited the halftone illusion in his wall-size portraits.)

And modern electronic images are printed the same way. Software converts the pixels with their millions of red-green-blue (RGB) values to halftone dots in their different sizes and orientations of cyan, magenta, yellow, and black (CMYK) sizes. (RGB are transmissive primary colors; their complements, CMY, are reflective primary colors.) If you look through a magnifier at a comic strip or at, say, a chart with tinted areas, you’ll see round dots. Those work pretty much the same way as halftones, inasmuch as the intensity of the color you see correlates with the percentage of the paper surface covered with ink. But those dots are generated from equations, not by processing an image with a screen. Those  dots have an interesting history, if you want a diversion. You may also be familiar with them in another context: paintings by Roy Lichtenstein.

Three common misconceptions about self-publishing

You will find—have probably already found—a great deal of advice and information floating around the Web. Some of it is great. Some of it is okay. Some of it is just wrong and can lead you well astray of the path you want to be on. Here are three of the biggest false beliefs I encounter. This is by no means all or even most of the myths that are out there. But these are major ones.


1. Printing a book is publishing a book

Publishing a book is making it available to the public. You may be interested in selling the book at a profit, as most publishers are. Or you may just want to get the word out there. But the key is that you’re making it public.

You may not be interested in selling books or indeed in making your book public. You may, instead, want to end up with a privately printed book that you can give away to your family and friends, to your clients and prospects, to your customers and employees. From a production standpoint, almost all the steps to produce the book are the same (you don’t need to create a publishing imprint or buy ISBNs, and you may decide to forgo registering the copyright).

But if you are publishing the book, then you need to attend to working out a marketing plan and executing that plan (often the tail that wags the dog), dealing with the various bureaucratic requirements of establishing a publishing business (even if this is the only book you’ll ever publish), and keeping good records.

Before you seek services to help you reach your goal, have clear in your mind whether you are publishing a book or just making a book that you are not publishing. If you are publishing a book, then you are a publisher. You can drop the “self” part whenever you feel ready to do so.

Here is a Venn diagram that shows the relationship between making books and publishing books.

Venn diagram. Two overlapping sets: printed things and published things. Some kinds of books are printed but not published. Some published things are not books.

2. It’s not self-publishing unless I do it all myself

Self-publishing does not mean do-it-yourself publishing. Yes, it’s fun to learn new skills. But doing anything well requires training and experience. Producing a book is no different in that regard from any other kind of craft activity. You can find all sorts of advice on the Web and books in the bookstore on how to put out a DIY book, and if you have zero budget, you can do that. But don’t expect it to win awards for production values.

If you are the publisher, then think like a publisher. Decide what level of quality you want in the finished product. Figure out what aspects of the overall publishing process you have the needed skills for (as well as the time to do them). Figure out which aspects you would do well to hire a craft expert for. Can you edit your own book? Maybe, if you’re an experienced editor and are able to do what most editors cannot do, which is to edit your own work. But if you have no training or experience as an editor, this is not a good practice. Can you do your own interior book design and typesetting? Maybe you can find a template and do a passable job, and maybe that will be good enough for your purposes. But if you are planning to have a book that people admire, you should probably hire a professional book designer. Can you cobble together a cover from a template? Maybe. But most people will advise you to hire a graphic designer for the cover.

You’re no less a self-publisher for hiring professionals to do the craft work of producing your book. You don’t have to do that work yourself. You have enough work to do to market the book.

Here’s a flowchart showing the main steps in producing a book. See how much of it you want to take on yourself.

Be the publisher wall chart. Flow chart of book production process.

(A high-resolution 18ʺ × 24ʺ poster is available at

3. If I want to be successful, I have to use a self-publishing company

Think about that for a minute. The very term self-publishing company is an oxymoron. You are the only “self” involved. The company that wants your money is not the self. And they’re not putting money at risk. So they’re not the publisher, either. They are simply a vehicle for siphoning off any possible profits for themselves after you’ve paid the full cost of producing the book.

And what are they going to do in exchange? They’re going to upload your book to Amazon (something you can do yourself for free), and they’re going to post a thumbnail of your book cover on their own website, which is a place no one—NO ONE—thinks of first when they want to buy a book.

Are they going to connect you with highly skilled editors and designers? You have no guarantee of that and no control over who they select. You can do much better on your own.

And their “marketing services” do not include any actual marketing. You’re still on your own for that. As the publisher, you’re responsible for connecting with the audience for the book and telling them where they can purchase it. Any money you pay to a vanity press for marketing just goes straight into their pocket, with nothing to show for it.

Bottom line

If you’re self-publishing, be the publisher. Work with skilled professionals to produce the book you want. Take off your author hat and put on your publisher hat. Think like a business person. Work collegially with your team. And don’t quit your day job.

Printers, publishers, and . . .

Earlier this morning, on a mailing list, someone trying to sort out a list of printers began to ask a question by positing “There are many, many on-demand book printers/publishers online, some with very low prices.”

I responded as follows:

Stop. Right. There.

You’re dumping alligators, seaweed, hippopotamuses, and pond scum into one bucket just because they all live in water. So let’s try to sort them out into categories. Then it will be much easier to compare services and prices.

REGARDLESS OF WHAT COMPANIES CALL THEMSELVES OR SAY THEY OFFER, what we’re interested in is what they are and whether they provide the services we need. So let’s use our own bafflegab-free definitions and ignore the marketing materials.


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  • A publisher is someone who puts money at risk to produce and market a book.
  • A publishing services company is someone who provides services such as editing, design, indexing, or proofreading to publishers.
  • A book packager is a company that prepares books for publication on behalf of a publisher.
  • A printer is someone who owns printing equipment and accepts customer files for printing.
  • A book manufacturer is someone who prints and binds books under one roof.
  • Offset printing is printing from metal plates hung on a press and is typically used for 300 or more copies of a book.
  • Short-run digital printing is using digital printing equipment to produce one or more copies of a book for delivery to the publisher (or to a fulfillment warehouse).
  • On-demand printing is using digital printing equipment to produce a single copy of a book for direct delivery to a retail customer on behalf of the publisher.
  • A print broker is someone who accepts a job from a publisher and then forwards it to selected vendors for the required services.
  • A vanity press is a company that combines the services of a publishing services provider and a print broker and overcharges for both, making it impossible for a publisher that contracts with them to make a reasonable profit. Otherwise known as pond scum.

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Now, WITHIN A CATEGORY, it is possible to compare companies and evaluate whether one provides better quality or better services than another, and that can be a productive exercise.

There are book manufacturers who specialize in working with amateur publishers (high school yearbook staffs, for example) and have customer service reps (CSRs) who are adept at hand-holding.

Some of these companies also do a superb job of book manufacturing. Others tend to cut corners.

In contrast, there are book manufacturers whose CSRs are nothing more than traffic managers (friendly, competent, polite traffic managers). Any technical questions are forwarded to a technician, and the answer that eventually comes back may or may not be clear. These companies work directly with professional print buyers at publishing companies and with professional book designers, customers who are expected to provide trouble-free files for printing and clear specifications for the job. Within this subgroup of book manufacturers, some companies focus on quality and some focus on price.

Similarly, with short-run digital printers, there are companies that specialize in book manufacturing for publishers, and there are others that specialize in church cookbooks, machinery service manuals, and programs for the local high school football awards banquets. And, oh yeah, if you have a book of your weekly newspaper columns from the local shopper, they’ll throw that together for you too. So, again, you can compare on quality and price.