While our creation tools will warn you if image resolution isn't high enough to print well, it's impossible for our tools to identify and warn you about issues like grainy or blurry images, jaggies or compression artifacts.
Here are some tips to help you review and adjust your images before going to print, so as to avoid grainy, blurry, or pixelated photos appearing in your book.
Use the 200% test
Images may look fine from a distance or when viewed on a camera or phone but a close-up view will reveal any flaws. If you have any doubts about your image, use a photo-viewing program to zoom in on your image to 200% and see how it looks. (If you’re uploading a PDF to Blurb, you can do the same test with the PDF).
This is a useful check for any image, but we especially recommend that you perform the 200% test on any images you convert from other sources, like a PDF or Word document, or any scanned images.
How to zoom to 200%
Using a Mac: zoom in with Preview and follow these instructions.
Using Windows: follow the steps below to zoom in on an image.
- To change the magnification level gradually, in Filmstrip or Single view, use the Zoom slider
- To view a picture at a specific percentage, in Filmstrip or Single view, click the arrow next to the Zoom box on the Standard toolbar, and select the setting you want
If you’re previewing a PDF we recommend using Acrobat Reader.
If your image looks sharp and not grainy at 200% then it should look great in print. (See the example images below).
Although the 200% test is useful, your printed Blurb book is the ultimate test. (The 200% test won't tell you if your image is too dark to print well, for example). If you plan to order multiple copies, you should always order a single Blurb-printed proof copy and review first.
What if my images look bad at 200%?
If your original images look grainy, blurry, pixelated, or jagged at 200%, they will look that way (or worse) in print. There is no perfect way to fix poor quality original images. Attempting to fix the images (by sharpening them in Photoshop, for example) can only do so much and may actually make things worse if overdone.
The best solution is to ensure that your original images are as sharp and clear as possible.
How to avoid grainy, blurry, or pixelated images
1. Avoid a high ISO setting on your camera
When taking photographs, make sure your camera's ISO setting isn't too high. By keeping your ISO setting as low as lighting allows, you will minimize the risk of grainy images.
There's no magic setting, and every camera handles ISO a bit differently, but as a general rule, the higher the ISO, the more likely you'll encounter digital noise and grain in your images.
2. Avoid using low resolution images
While low resolution images might look fine on your monitor, depending on how big you stretch them for your printed book, they may not print well. Our book-making programs will alert you when the image you're trying to use has a low resolution.
If the low-res warning appears, reduce the size of the image on the page until the warning goes away. (Remember, the low-res warning only checks the size of the image. It can't detect blurriness, grain, pixilation, or over dark images).
3. Steady the camera
One common cause of blurry images is camera shake. You can avoid that issue by stabilizing your camera with a tripod. Additionally, using the timer setting on your camera or a remote-control shutter release can help to eliminate camera shake.
If you’re shooting with a phone, you become the tripod! Steady yourself against something if possible.
4. Focus, focus, focus
When taking photos, be sure to focus on your subject. Out-of-focus images won’t print well. If you're shooting portraits, the general consensus is to make sure your subject's eyes are in focus over anything else.
Here's a screenshot of an image viewed at 100%. It doesn't look so bad at first glance...
...but here's the same image zoomed to 200%. Notice how it's actually blurry and nothing's really in focus. It will look just as blurry in print.
Here's another (and sharper) image at 100%.
Here's the same image zoomed in on the hat. Notice it's still relatively sharp, with sharp lines and no strong grain, unlike the previous example.