What does BookWright's 250 PPI info mean?
The 250 PPI info seen in BookWright's File Size/Image Size section indicates the maximum size the image can be printed while still maintaining our recommended minimum of 250 PPI.
This does not mean BookWright has reduced your image’s original PPI. For example, if your image was 300 PPI at 8x10 inches to begin with, it will still be 300 PPI if placed/printed at that size.
Read on if you'd like more details about the File Size/Image Size feature and how PPI works.
The File Size/Image Size section
After you import images into BookWright you'll see a thumbnail preview of each imported photo at the top. (Go to View>Photos if you don't see this section). Here's an example with three thumbnails:
You can hover your cursor over each thumbnail, or double click the photo, and see the FileSize/ImageSize details as seen here:
What do the File Size/Image Size details mean?
The File Size/Image Size details show you the maximum size at which the image can be placed/printed while still maintaining a resolution of 250 PPI/pixels per inch. (250 PPI is the minimum resolution we recommend).
In this example, the maximum size to retain 250 PPI is 12.1x16.1 inches.
| Tip: as you increase the dimensions of an image, that redistributes its pixels and lowers the PPI. If you spread the pixels too thin (below 250 PPI) by making the image larger, the reduced PPI will trigger BookWright's low-resolution warning. |
What if my image's PPI is 300? Will BookWright lower the PPI?
The 250 PPI info does NOT mean that BookWright has automatically lowered the PPI of your original image. If your image is, for example, 300 PPI at 7.5x10 inches, it will remain 300 PPI if you place the image at 7.5x10 inches.
But if you place the image at a larger size--like 9x12 inches--that will spread out the pixels and lower the PPI. That's just how digital images work.
More about PPI
PPI (pixels per inch) refers to density of pixels at a specific size. This is why you'll see resolution and PPI talked about as 300 PPI at 8x10 inches or 250 PPI at 3024x4032 pixels or 300 PPI at the size you want to print. That is, PPI is talked about in the context of dimensions.
When you place an image onto the page or cover of your book, BookWright must redistribute that image’s pixels to print at that size/those dimensions. (Unless you happen to place the image at exactly its original dimensions, which often isn’t the case).
If you place the image at a larger size, BookWright will spread out the pixels to fit the larger dimensions. This can reduce the PPI because the pixels have to be redistributed to cover the larger area.
If you place the image at a size that spreads the pixels too thin--under our 250 PPI minimum--that will trigger BookWright’s low-resolution warning.
Blurb's other bookmaking programs and workflows have similar warnings: if your image is placed too large to maintain the recommended PPI, you'll see the low resolution warning.
What if you see the low-resolution warning?
If you see the low-resolution warning then you should make your image smaller on the page until the warning goes away. Or use a different image that doesn't trigger the low-resolution warning at that size.
You can choose to ignore that warning but the quality of the printed image may suffer and we can't offer replacements for low-resolution images or other content-related issues.
The 200% test
Finally, it's always a good idea to give your images the 200% test and look for any potential issues which the low-resolution warning isn't designed to catch, such as graininess or blurriness. Any issues you see at 200% zoom will look that way (or worse) in print.