Color inside the book, and what it costs
Color inside a book is not a formatting choice. It is a per-copy manufacturing cost, charged again on every copy for as long as the book is in print, and it is the one production decision that can quietly make a book unsellable.
The cost repeats forever
Most of what you spend on a book is spent once. Art, editing, a stock license, the hours you put into the interior — you pay, and it is done.
Print cost is different. Every printer's payment math starts by deducting what the copy cost to manufacture, and only what is left is split. A color interior raises that deduction on every unit, which raises the list price you have to set before the book earns anything at all.
On a short, heavily illustrated book that is survivable. On a 300-page color book the floor can land well above what readers in your category are used to paying, and no amount of marketing fixes a price that is double the shelf around it.
Rates, bands and cutoffs differ by printer, by trim and by territory, and they change. Do not take a figure off a blog. Run your real page count through your printer's own cost calculator before you design anything around color.
Two things put a book in the color bracket
Any non-neutral ink anywhere on a page. It does not have to be much. A colored chapter number, a blue hyperlink left live from the manuscript, a logo on the copyright page, one line of text still highlighted from editing. A page is either black-and-white or it is not.
An image that is nearly gray but not exactly. This is the one that catches people, and it catches them after upload. Neutral means every pixel has equal red, green and blue values, or lives in a single black channel. An image desaturated with a slider, scanned from a print, or exported from a phone that applied a warmth setting can carry pixels one or two levels off neutral. That is invisible on your screen and completely unambiguous to the printer's file check.
How you are then billed varies. Some printers count the pages that carry color; others price the whole interior as color if a single page does. Which one you are dealing with decides whether a plate section saves you anything, so find out before you build one.
What converts to grayscale, and what breaks
Photographs usually convert well. They are tonal to begin with, and a portrait or a landscape in gray reads as a deliberate choice rather than a loss.
Anything where color carries the meaning does not convert. It breaks. A red line and a green line of similar lightness become the same gray, and a chart with a five-color legend becomes five indistinguishable strands. The same happens to maps, transit-style diagrams, heat scales, pie segments and anything with a color key.
Those figures need redrawing, not converting. Separate the lines by weight, by dash pattern, by direct labels sitting on the line itself. Separate areas by hatching or texture rather than by fill color. If you do use grays, space them widely in lightness — four grays a step apart look identical once ink spreads into paper.
The test takes a minute. Convert the figure, print it on any home printer, and read it at arm's length. If you cannot tell which line is which, your reader cannot either.
In the Interior Formatter. It sets interior ink for black-and-white printing, so the type and the page itself are neutral by construction, and it checks every image you place against the size it will actually print at. What it cannot do is decide whether your figures still make sense in gray. Start a book → · about the Interior Formatter
The four ways out
Go black-and-white and design for it. The best outcome when it works. Commission or redraw the figures as line art from the start, and the book looks intentional rather than drained.
Put the color in a plate section. Group the images into one block of pages instead of scattering them through the text. Only worth doing where your printer bills color by the page — and the images then sit away from the text that discusses them, which is a real cost to the reader.
Sell a color edition beside a black-and-white one. A separate edition, its own ISBN, its own higher price. Readers who want the plates buy them; everyone else buys the affordable copy. This is what illustrated nonfiction has always done.
Move the color to the ebook. It costs nothing there. A screen has no ink and no page count, so the same photographs that break the economics of a printed book are free in the EPUB. See EPUB and print PDF are two different books.
The check before you upload
Confirm every interior image is genuinely neutral, one by one.
Open each in an editor and read the pixel values under the cursor — in a highlight, a midtone and a shadow. Red, green and blue should be equal at all three. Convert to a grayscale mode rather than pulling a saturation slider to zero; the mode conversion cannot leave a residue, and the slider sometimes does.
Then sweep the text for the small things: hyperlink blue, colored table rules, a heading style with a tint on it, leftover editing marks, a publisher logo in a near-black brand color, and a title page that reuses the cover art. Any one of them recolors the book.
Confirm it in the file and confirm it again on paper — see Preflight: what to check before you upload, then order a proof.
Make yours
Everything here is built into the tools, and they are free to use: name your book, bring your manuscript or your artwork, and work as long as you like. You only pay when you want the files without the preview watermark.
Next: Paper weight, cover finish, and how the book feels · More: Putting images inside a book · White or cream paper? · Pricing a self-published book