Image Quality: High Hopes For High Resolution
It seems that not a week goes by without the need to request (and explain) a hi-res or high-resolution graphic image or photograph from not just clients, but other designers and printers as well. These are cases in which they would like to use their own supplied image for adding to their website or for use on a printing project. We understand. Many terms and jargon associated with graphic design and digital graphics tend to be confusing to the general public. Our hope is that this article can help.
A good start when asked to send a hi-res or high-resolution image is to consider it as a reference to image quality. Resolution is basically the quality of the picture. When resolution increases, the image is more clear and more detailed. It becomes sharper because more information is included within the space.
Think about tiny dots. Now envision the difference between a few large dots and thousands of tiny dots. The more dots that can fit into an image, the higher the resolution. Fewer dots means lower resolution and less clarity. Dots are used as descriptive word when it comes to images for use in photography or printing. Pixels describe the specks of a digital image for use online or for viewing on an electronic screen.
Thus, it is really important to begin with a quality image with the highest resolution and dimensions that can be reached. Bigger is really better. One can decrease the size of an image or graphic design, but cannot increase up in size from a small or lesser resolution image without losing sharpness and quality.
DPI means dots per inch, or the amount of dots that fit horizontally and vertically within in a printed inch. More dots means higher quality and detail. 300dpi is the most common standard for printing clearly. 300dpi means that when printed, each square inch of your image will contain 90,000 pixels (dots), the higher the dpi (the more pixels per inch) the more crisp the printed image will be.
PPI means pixels per inch used to denote the pixel density of an electronic screen or of a digital image. Basically, a pixel (px) is a monochromatic dot used to represent a small part of an image. PPI is interchangeable with DPI when referring to image resolution in most cases. For example, a monitor displaying a resolution of 800 by 600 refers to a screen capable of displaying 800 pixels in each of 600 lines, which translates into a total of 480,000 pixels displayed on the screen. A typical image on the web is 72dpi whereas when printing, files must be 300dpi or higher at full size. Scaling a 72dpi image up to 300dpi is not recommended and will result in a blurry image.
Resolution is the measurement of pixels or dots within the image or display. Expressed as measurements of width by (x) height. Resolution does not refer to just size. Image files with a higher resolution (high dpi) will also be a larger file size due to containing more data. Image size is not the same as file size because image size refers only to the dimensions of the actual image – the file size is the space the file uses in kilobytes or megabytes.
The best file type for a graphic is Vector. Vector graphics allows the designer to expand or reduce the vector graphic in size without any loss in quality using curves, points, lines and polygons.
An image is said to be rasterized when transformed using photoshop or illustrator from vector image to a bitmapped image of pixels. When opening a vector image in a bitmap-based editing program, you are generally presented with a dialog box of options for rasterizing the image. Rasterizing is the process of turning vectors, or text layers, or layer effects, or any other kind of graphics, into a simple bitmap image made of pixels. A rasterized vector file resolution can not be changed without affecting the quality of the image. Ideally, graphic images destined to be printed should be first prepared as vector images, since vector images are resolution-independent – meaning that they will print at the highest possible resolution.
When you are asked to send a high-resolution version of an image previously provided, do not simply try to enlarge it or increase the PPI as this will not improve the quality and sharpness. Try searching for the original graphic or photo as it was first created. Once you have found the file, it could be emailed directly as an attachment, or if it is larger than 25MB, upload to Google Drive, Dropbox, or any other file sharing site. Please “zip” large native file types to avoid file corruption.
Recommended file types: .ai, .eps, .psd, .tif. .jpg, and .png
In summary:
• The higher the resolution, the happier your Graphic Designer will be.
• 300dpi for print / 72dpi for web
• Vector Graphics can be scaled without any loss of quality or sharpness.
• Raster images are made up of pixels and lose quality when scaled up, but not down.
• Image size along with dpi is very important. An image that is 4”x6” (1200×1800 pixels) @300dpi will print nicely at 100%. An image that is 4”x6” @72dpi would equal 288×432 pixels and will only be 0.96” x 1.44” in size when printed at 100%.
• Vector Graphics are created using Adobe Illustrator and Raster Graphics with Adobe Photoshop.
Want to learn more?
Our Glossary of Terms page may help familiarize you with common terminology.
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