Pixels – Does Size Matter?
The short answer is as normal, yes. I get asked all the time, “will this logo on my business card work?” Sometimes, and here’s where the digression begins. We hear of cameras sold in Megapixels (1000s of pixels), printers printing in DPI (dots per inch, typically 150-600 dpi) and the computer screen displaying this story is defined in resolution (mine is 1280 x 1040).
They are all basically saying the same thing – how many dots or pixels are there across the top of a rectangle picture and how may are there down the side. Simply stated, an image that is one inch wide by one inch tall displayed at 72 dpi would have 72 pixels across the top and 72 pixels down the side. Multiply them together and you’ll find that the image would have 5184 pixels in total. You guessed it, 300dpi is 300 across and 300 deep for 90,000 pixels total, or about 17 times more pixels for the same one inch image – here the pixels are smaller and give a more blended visual and depth of detail and colors.
Each pixel displays a different color and the computers know the numerical number (ie one number for each of the 16 million colors of your computer screen – yep, I’m glad I don’t have to remember them either!). It stands to reason then, the less the quantity of numbers to remember, the smaller the file size. So most images on the internet/email are best designed at 72 dpi and having various quality protocols that give the images endings like .JPG or .PNG or .GIF. These are generally considered low resolution images.
Begging the question from above, many times internet images can work depending on their size. Some 30 inch by 30 inch images at 72 dpi may be better than a one inch 300 dpi, again depending on whether it’s a graphic or picture of say a person. Below you’ll find a picture of my daughter with a snapshot from a pocket camera from yester year on the left, a nicer digital photo in the middle, and a crop out of an iPhone image borrowed from her Facebook. Look closely and you’ll see some difference. For those with eyes like mine or would be viewing from a distance, there’s another one example below that zooms in on the difference of 72 and 300 dpi from ole Digi holding up a sign at the top of the page ((JPG image at 600 x 817 pixels at 72 dpi).
If the camera shot was grainy, poor lighting, or from a low quality capture (small Megapixels) on the camera, the result will be more like the right photo, especially when zoomed in say to capture a face, where there were three people in the shot.
If the business card has a nice crisp print and the logo is graphic, we can scan them at 1200 dpi, upsize it, run some defuzzing routines on it and most times it can work out when scaled back down.
We try to design everything in 300 dpi so that it can be used for either traditional vinyl printing (needing 300 dpi) or for digital billboards needing less pixels due to the limited number of LEDs on the signs.
So yes size does matter, and the better the images that we start with, the better flexibility and outcome of the layouts.