What are the new dpi and pixel rules for ibook cover art?

Are your images jpegs or pngs? Photos or graphics?

The new iPad is 264 dpi, but...you should work with your images (preview on a device) to determine the best payload vs. display quality recipe for your content.

Ken

Your cover has to have at1400 pixels in the smaller dimension. Forget about dpi. An image doesn't have a dpi, only a display does.

Michi.

Image dpi has a direct effect on image quality. Don't ruin the finished product by ignoring something under your control.

Speak up if you need suggestions on tools, techniques, etc.

Ken

K T wrote:

Image dpi has a direct effect on image quality.

An image has no dpi, only pixels. What has dpi is the display that shows the image.

The pixel dimensions are an attribute of the image and determine how much information is in the image. The dpi is an attribute of the display and determines how many pixels are displayed in a given area.

The two values are independent and have nothing to do with each other.

If a program such as Photoshop or InDesign allows you to specify a dpi setting, it is so it can export an image with pixel dimensions that match the dpi of the target display, so the image appears at a pre-determined physical size. The programs also use the dpi setting so, when you ask to be shown the image at original size, the software can scale the image so it appears at that size even on a display whose dpi does not match the dpi of the target display.

When you upload a cover image, there is no dpi. There is one and only one thing: the pixel dimensions of the image.

Michi.

MichiHenning wrote:

Your cover has to have at1400 pixels in the smaller dimension.

Sorry for the typo. That should have read "… at least 1400 pixels in the smaller dimension."

Michi.

That information is out of date, I'm afraid. From the latest Producer Guide (2.7.1):

Cover art (also known as a marketing image or jacket) should be at least 1400 pixels along the smaller axis and must be a JPEG or PNG file in RGB Color mode. For an average trade paperback, this could be 400 x 1400 minimum size, as the books are generally taller than they are wide. For best results, deliver the largest pixel dimensions possible. When possible, match cover art to the cover contained in the book file. The 2 million pixel maximum does not apply to the cover image.

Michi.

Thank you for clearing up the ongoing confusion about pixels and dpi. The Apple guidance has now dropped all reference to dpi and quotes pixel size 1024x768 for the normal iBook page. Perhaps this is an important fact to go in the TIPS Section as soon as possible.

Ken