With Digital Photography, you can have much more influence on the final outcome than was possible when film was the only option. Back then, you concentrated on the photo, and the developing lab did the rest. Nowadays, it is not too difficult for the photographer to take a few easy steps that can have a positive effect on the completed printed photograph. Resolution is key, and the digital photography tricks below will help you understand how to apply this correctly, using Adobe Photoshop or similar post-production application.
Digital pictures are made up of millions of tiny squares, known as pixels. How many pixels an image has determines the resolution, and therefore the quality, of the picture. A typical 6 megapixel camera will take a shot of 3000 pixels by 2000 (multiply the two, and you reach the 6MP figure). Knowing this, we can now turn an image into a small or large print, depending on how tightly, or loosely, we spread the pixels out. For example, if we were to place 300 pixels into one linear inch, our final image would be 10 inches wide, by 6.66 inches tall.
With your chosen photograph open in Photoshop, for example, its pixel dimensions can be found by selecting the “Image” button and choosing “Resize” and “Image Size” from the dropdown. Once you know the pixel dimensions of your image you simply divide the width and height (both shown in the “Pixels Dimension” box) by the image resolution (i.e. the pixels per inch – ppi – are shown in the “Document Size” box). This tells you how big your image will be. Typing relevant figures in the boxes can alter all pixel Dimensions and Document Size values.
So, when applying these digital photography tricks, how do you know which ppi figure to select? Well, standards have been established, with the accepted ppi for photographs in the publishing world being 300ppi (high-quality publishing and professional work). At home, a photo quality inkjet printer will give excellent print quality at 240ppi. For a picture to be viewed from a yard or more (maybe a framed wall print) even 150ppi will suffice. By the way, if you are using an image purely for use on a computer screen, or the web, just a low resolution of 72ppi is required, because of the way screens behave compared to actual prints.
In summary, you can see that print size does not mean much until you have the ppi figure to go with it. For example, by simply altering the spread of pixels, a 7 inch by 5 inch print can be created from any digital image. Therefore, if you need a 7in by 5in print at 240 ppi, you know you require 1680 (7 x 240) by 1200 (5 x 240) pixels to produce it. You can play around with the values in the “Document Size” box in Photoshop to see the effect it has. Apply these simple digital photography tricks next time you need to print images, and you will ensure they are of the desired quality before you click the “print” button.
