You are most likely reading this article because you are concerned about the color output of a book you are looking to print, or we are reviewing a sample you have returned for accuracy.
The first thing that needs to be reviewed, is color modes, and how they effect 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 effect the Delta E reading
Here at Bookbaby, we strive to be at a Delta 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, except for if you were to order a larger offset run. 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 can not 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 effect your perception of color. There are many tools out there to aid with monitor calibration, but one that is affordable and very easy to use is the X-rite ColorMunki display. It will take readings of the ambient light in your room, as well as your monitor to 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 $39 proof book.
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.