Why aren’t my photos good enough? Why can’t you use my logo? (part 2)
[Imagine whiny voice]: “But my photos looked good on my computer screen!”
In part 1 of this blog post, we talked about why you might have had trouble sending your logo—or any design you created—off for printing because it was the wrong type of image file (i.e. vector vs. raster art).
Before you get offended, please know that your artistic friends are not simply trying to make life difficult for you. They actually want to help you make your finished project look great, but they are pretty much powerless to do so if your photo resolution isn’t high enough.
But it looked great on your monitor, right? Right. The reason is because your screen resolution displays at 72 pixels per inch (ppi – remember our previous blog post about what pixels are?)
Your designer/printing company is telling you the resolution isn’t high enough because professional offset printing typically requires at least 300 ppi. You may be thinking, “Three HUNDRED? What? How am I supposed to get a photo with quality that high?”
Never fear, Gajdek Graphics is here to put your mind at ease. True, if someone else originally sent you the faulty image, you may have to chase them down and get a higher-resolution version of it. However, if you took the photo yourself, chances are all you need to do is just find the original photo on your camera or on your computer (if you transferred it from your camera.)
Nine times out of 10, your digital camera already had the proper settings when you took the photo in question. It may have been set to take photos at 72 ppi, 96 ppi, 180 or 230 ppi. So that’s a problem, right? Those numbers, after all, are less than 300 ppi. But wait! You’re probably just fine. This is where explaining things gets a little hairy, though. Bear with me; it will turn out all right in the end!
I’m going to use a little table to shed some light on how this works:
|High resolution/Small physical size =POSSIBLY GOOD||High resolution/Large physical size =GOOD|
|Low resolution/Low physical size =SORRY, CHARLIE||Low resolution/Large physical size =POSSIBLY GOOD|
As you can see, resolution is not the only deciding factor on whether your image will print well. The actual physical dimensions also play a role. That is why if your camera is set to 72 dpi but it takes photos measuring 25” x 25,” you won’t have a problem unless you’re printing something colossally huge, such as a banner. A good quality image editing program such as Adobe Photoshop or the less expensive Photoshop Elements will allow you to view a photo’s physical size and resolution by going to the Image Size dialog box in Photoshop (Image > Image Size) or Photoshop Elements (Image > Resize > Image Size).
Say, however, that your photo is 96 ppi and measures a respectable 5” x 7.” Sounds pretty good, right? Well, while increasing the image resolution to 300 ppi, you need to offset that increase by decreasing the physical size, in this case to 1.6” x 2.24” (96/300 = 0.32 x 5” = 1.6” and 0.32 x 7” = 2.24”). This is what’s known as resampling the image.
You can do this using Photoshop, or if you don’t have Photoshop or a comparable program, you can ask your designer/printing company to adjust it for you.
If you want to make sure that you adjust the resolution and size correctly, compare the file size (in megabytes or kilobytes) after your adjustment to the file size before the adjustment. If you did the math exactly right, the file size will be exactly the same.