You are most likely reading this article because you are concerned about the color output of a book you are planning to print, or because we are reviewing a sample you have returned for accuracy.
The first factor that needs to be reviewed is color mode and how it can affect your output.
Please make sure you have reviewed this article:
https://support.bookbaby.com/hc/en-us/articles/115012581727-RGB-Spot-colors-CMYK-Oh-My-
A device called a densitometer is used to measure the ink density on the printed sample. This is measured against the PDF your book was printed from. The difference between the two is expressed as the "Delta E" value.
In order to speak on the same terms for color evaluation you can reference this chart
| Delta E | Perception |
|---|---|
| <= 1.0 | Not perceptible by human eyes. |
| 1 - 2 | Perceptible through close observation. |
| 2 - 10 | Perceptible at a glance. |
| 11 - 49 | Colors are more similar than opposite |
| 100 |
Colors are exact opposite |
This is a way to speak about color based on empirical data, rather than perception of the human eye. The readings are based on reproduction on gloss stock.
Factors such as image resolution and the paper stock used will affect the Delta E reading
Here at Bookbaby, we strive to be at a Delta E of 5 or better, but in many cases up to an 8 would be deemed an acceptable commercial standard.
Bookbaby does offer single copy proofs that are run on the same digital presses as the full orders.* We suggest everyone order one of these proofs to see your file in print before placing your larger order.
The other part of this that we cannot control is your monitor calibration. You may like your monitor very bright, or the room you are viewing your files in may be dim. These factors and many more all affect your perception of color. There are many tools out there to aid with monitor calibration, but one that is affordable and easy to use is the Calibrite ColorChecker Display. It will take readings of your monitor and the ambient light in your room and adjust your settings to display as closely to a printed sheet of paper as possible. Unless you are a designer or photographer, this may not be a worthwhile investment for you, when compared to the cost of a $99 proof book. And professional designers and photographers who have color-calibrated monitors would still want to get a physical proof.
If you are utilizing proper monitor calibration, along with our color profile (found here https://support.bookbaby.com/hc/en-us/articles/220379028-Do-you-have-a-color-profile-I-can-use-), you should have very few surprises when it comes to the output of your book.
* Proof copies and full orders are run on the same digital presses except in the case of a large (~2500+ copy) order printed on offset, rather than digital, presses