This artice will give you a better understanding of “Resolution” that we face at every day work..

Credit – www.frameworkanimation.com

The Basics of Resolution:

Many people struggle with the term ‘resolution’, both with it’s meaning and with how to properly use it. The basics are not that complicated once a couple things are understood. First off, what is resolution? I would define it as the visual density of colour information within an image, measured in dots-per-inch, or dpi, as typically seen on your computer screen, on TV, or on a sheet of paper. Most of the discussions I have on resolution are to do with image files destined for print.

There are two types of resolution involved in this:

• For your printer, the number of dots of ink counted in a straight line within the space of one inch gives the dpi value.
• For your computer screen, the number of pixels in a straight line intended to be printed within the space of one inch gives the dpi value. This is the value that most people are concerned with as they create and request graphics.

In both cases, the higher the dpi value, the higher the resolution.

When describing the resolution you need in a rendering (or any other image), a dpi value alone doesn’t actually provide a complete picture (pretty punny eh?!) This is because to fully describe resolution, it needs to be paired with dimensional information. For example, a 4″x6″ image at 300dpi is quite different than a 2″x3″ image at 300dpi. The former contains approximately 4x the amount of information of the latter. Correspondingly, the file size is also 4x larger. But they are both 300dpi!

When you need to request an image at a specific size you should give a dimension, in at least one direction, and a dpi. i.e. “I need the finished rendering to be 36″ wide at 150dpi.”

We try to make this easy for you by providing renderings in at least three different sizes to suit most common purposes. Descriptions of these sizes and their suggested uses can be found on your page in our ClientZone.

Some further detail for those who really want to understand this kind of thing:

So, what resolution do you really need for various things? Well, that varies with the purpose of the image.

First, let’s look at a couple physical limitations of printers:

• A printer always prints out at it’s specified dpi, regardless of the resolution of the image you fire at it. If you send two images to a printer, one at 300 dpi and another at 100dpi (sized to the same physical dimensions), a 600dpi printer will print them both using 600 dots of ink to an inch. The difference will be that the 100dpi image will appear fuzzier or less detailed than the 300dpi image.

• Suppose your standard CMYK colour printer claims to print at 300dpi. Would you be surprised to learn that sending it an image over 150dpi is actually overkill? This is because the printer actually requires 2 dots of ink stacked horizontally and 2 more stacked vertically on the page to represent one colour. To simplify things, let’s only think in terms of the horizontal (left-right) travel of the print head. The printer can place 300 dots of ink within one inch. But it actually requires 2 dots to represent one colour. This effectively halves the image resolution required to max out the quality the printer is capable of. Half of 300dpi is 150dpi. A printer that can do 1200dpi would max out with an image at 600dpi. If you know a little more about printer technology then you’ll realize this is a bit simplistic, but it’s basically valid.

OK, is that all there is to it? Sorry, no!

One could say that a higher resolution is always better than a lower resolution so just ‘give me everything you’ve got!’ The problem is that higher resolutions equal larger file sizes and, speaking in terms of creating renderings, longer production times. Doubling the resolution of an image actually quadruples both the file size and the production time. Very large files can also become much harder to work with in programs like Photoshop and to transfer via the Internet or on disk of some kind. It makes sense to settle on a resolution that balances the specific need for image detail while maintaining a reasonable production time and file size.

So what is the specific need for detail? It’s a bit subjective, but as a rule the closer the viewer is likely to be to the print, the higher the resolution should be. In my experience, very few people can tell the difference between resolutions in colour images over 300dpi. So I always consider this to be the absolute max value required for anything. Here are some specific examples:

• Hand-held prints are most likely to be closely scrutinized by the viewer at distances as close as a few inches. A letter-sized print can certainly be produced at 300 dpi with excellent results while maintaining a production time/file size balance. Even here though, you can get away with lower values; 200dpi is not unreasonable.

• Display boards for presentations commonly range from 24″ to 36″ wide. These are usually viewed from at least a few feet away. I’d aim between 200dpi and 100dpi in these situations.

• Sales centres often have very large wall prints and require that a balance be reached between resolution and production time. A wall print can be viewed as closely as a presentation board, but to produce the same resolution on an image that could be 8′ tall might be prohibitive. Of course, to really ‘take in’ an image that’s 8′ tall, you do need to stand back from it, and that works in our favour. I’ve done renderings that were printed 16′ wide and 8′ tall at 75dpi and was actually shocked at how great they looked, even relatively close up.

• Images for hoarding fences or billboards are quite forgiving since they are meant to be viewed from a distance. Images for hoarding signs can easily handle 75dpi, 50dpi or even lower. Billboards are often designed at 30dpi, but you’d never know it as you drive by on your way home from work!

One last recommendation specifically about printers. When producing images for close viewing, don’t use a printer with a resolution less than 600dpi. 1200dpi or more is ideal and easily done these days. Note: this is not the image resolution, it’s the resolution of the printer itself as explained above. This will ensure the best results, regardless of the resolution of the image you send to it.

I hope this has helped you understand how to strike a balance between the factors involved in determining the ‘right’ resolution for an image. Hopefully the next time the junior assistant at your printing service company tells you he needs 1200dpi for a 20′ billboard because that’s the resolution of his printer, you’ll know better!