Manufacturing Related FAQs

Below are some frequently asked questions with regards to the appearance of printed books. 

Why does the color blue turn purple when printed?
RGB blue is a vibrant and beautiful blue--however--because we do not print in RGB, the color has to be converted to CMYK. When RGB blue is converted to CMYK, it becomes a combination of 99.6% Cyan and 95.7% Magenta. This conversion results in a ratio of Cyan to Magenta that produces a purple hue, and this is how it will print.

RGB blue is outside of CMYK's gamut: CMYK simply cannot reproduce that shade of blue. The computer and software substitute the closest color to it. Technically, that color is purple. It's best to choose your blue in CMYK, and to be careful how much Magenta is in the values range––especially if the Magenta is as high as, or close to the same value of Cyan.

For covers of Black & White titles, we can accept an RGB file, and will convert it to CMYK before printing. LSI assumes that the designer of the file is aware of this RGB to CMYK conversion, and the potential to affect all colors (not just blue). We don't assume responsibility or make any adjustments to help a color maintain its original appearance. Most colors convert reasonably well from RGB to CMYK. These colors are within the overlapping gamut of each color space. Unfortunately, there are many colors that do not convert well. If the publisher/designer is concerned about how a file will convert, they should perform the conversion and make necessary adjustments before submitting files to Lightning Source.


Why does the printed book look different than on my computer monitor?
RGB is how computer monitors interpret and display color. The name stands for Red, Green, and Blue: these are the three colors of light that are added together to produce a vast range of colors seen on the monitor. Many colors viewable in RGB cannot be achieved by printing in CMYK. For that reason, it's important to carefully choose colors that will print well in CMYK.

CMYK stands for Cyan, Magenta, Yellow, and Black. These are the four pigments of color that are added together to produce the range of colors available in this type of printing.

We recommend working in CMYK and choosing the colors carefully in your file: referring to the values that make up the color, and not just its appearance on the screen. This will help you to ensure you're choosing a value that will print much closer to your intended selection.


Why does the Lightning Source printed book look different than printed pages from my home computer?
When using a home printer, there are a lot of variables that can affect the quality: calibration, paper type (weight, brightness, sheen/finish), ink quality & levels, settings, etc.

The printers Lightning Source uses are regularly calibrated for a consistent output (with reasonable variance) and are designed for high-speed output. Because these types of machines are so different from home printers, the output from a home printer can't truly be compared to our equipment.


Why is there a barcode on the last page of my book?
As part of the manufacturing process for POD books, Lightning Source adds a barcode to the last page of the interior of every book.

This is used to match up the interior book block with the cover. Additionally, we are required as a manufacturer to indicate where the book was manufactured. The barcode also provides further information about the manufacturing of each book if research is needed due to any issues with the finished product.

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