Last month I was working on a poster for a client. He’d sent over some photos, and I wrote back to tell him that I needed larger versions, at least 2500 pixels tall. He cheerfully answered “Cool, I’m blow them up for your tonight and send you the new copies.”
To which I answered, “You mean you’re going to get me uncropped versions of the original photos, right? You’re not just going to resample these small photos in Photoshop and send them again?”
I actually run into this problem a lot — and by a lot I mean at least five times this month, so I decided to put together a handy dandy little guide to explain exactly why your graphic designer is so insistent on getting higher resolution photos.
Bitmap Versus Vector:
Graphics aren’t magic. Unlike what CSI what have you believe, you can’t just push a button and crystallize a blurry image. The graphics on your computer screen hold data in two different ways, bitmap and vector.
Vector images store data using geometry. These images are composed of shapes, points, lines and and curves, all of which are stored in the computer using complex mathematical expressions. You can resize a vector image to any size without loss of quality. Vector images are always built using a computer. Common examples of vector images can be found in t-shirt designs, clipart, or company logos. Common vector formats include EPS, SVG, SVGZ, CDR, or AI.
Bitmap graphics store data as a series of tightly packed dots or pixels. Each of these tightly packed dots has a specific color. Photographs are always stored as bitmap graphics. Examples of common bitmap formats include PNG, JPG, TIFF, PSD, and GIF. When you look at a printed photograph, these dots are usually packed in at at least 300 dots per inch, while on a screen you’re usually seeing a mere 72 dots per inch.
When you increase the size of a bitmap graphic, these tiny dots get large enough that the human eye can see them. The computer tries to compensate by imperfectly storing the data in new pixels of the proper size. This causes blurriness and pixelation.
From The Screen To The Printer:
The more observant students in the class may have noticed an interesting discrepancy in the last section. I mentioned that screen media only displays data at 72 dots per inch, while print media displays at least 300. This means that an image that looks four inches wide on your screen would actually only print as a little less than one inch wide. So if your graphics are camera phone shots that you have cut and pasted from Facebook, be ready for them to be about an inch wide in print.
Getting High Resolution Shots
The more pixels that you have in the photo, the higher the level of detail. If your camera is taking high megapixel photography, then it’s packing tons and tons of these dots into the finished product and making a photograph that is “high resolution.” High resolution photographs can be printed at very large sizes without losing quality.
As a graphic designer, ideally I’d love to have all of your photos come from a professional photographer — but that’s not always realistic. Most modern dedicated digital cameras (and some of the newer smart phones) take high enough resolution photos for graphic design work. The key is to send the whole photo to your designer. Download the file and send it via email or upload it to Dropbox. Never filter your images through Facebook – it drastically reduces size and quality.
And though you may be sure that you know exactly where the photo should be cropped, send the whole photo to your designer with a description of which part you want shown. The raw photographs give us a lot more tools and options, and you’ll be happier with the finished product in the end.