What did we ever do before scanners? Are any of you old enough to remember mimeograph machines or better yet, do any of you remember hectographs? I smile as I remember, because scanners have obsoleted both of those technologies. It’s so much easier to duplicate pictures these days. And yet, a certain amount of technology has to be understood to obtain a professional result. It’s a bit more than slapping down an item and pressing Scan.
Six Elements for High-Quality Images
Here are six key elements to understand when you want to obtain high-quality images for the pictures you use when illustrating your documents.
* Halftones and Lines Per Inch (LPI) A photograph from your camera is a continuous tone image. To use this photo in a printing press, a screen containing thousands of dots on it has to be laid over it, another picture taken of it. This new picture is called a halftone. This process can be done using computer software and you’ll have the opportunity to choose the proper density, called Lines Per Inch. The higher the LPI, the smoother the look of the picture.
* Pixels Per Inch (PPI). I like the word pixel. It makes me think of Tinker Bell. Really though, a pixel is a unit of measure when scanning images. You’ve probably seen pixilated imaged on your cable TV from time to time. As in LPI, the more pixels, the higher resolution or quality of a pictures.
* Scanning Resolution for Print Images. Choosing the right resolution means you’ll have to evaluate the original image, the size you want to reproduce it to, and the output method you’ll be using like a laser or inkjet printer, or digital or offset printing. It’s best to scan your photo so that the PPI at output is twice the LPI. If your printer says he wants 150 LPI, scan it at 300 PPI. This avoids pixilation or bitmapping.
* Website Requirements for Pictures. There are no real standards when uploading pictures for your website, but if one thing is important, it’s the download speed. To enhance a speed download, keep your resolution around 72 PPI. This can keep clients from leaving your website because it’s too slow.
* Don’t Use Already-Been-Printed Photos. These photos have already been screened to half tones, and you won’t like the blurriness of them. Stick with originals from a good photo source site.
* A Handy Little Scanning Chart for Your Office
Output / Typical LPI / Resolution (PPI)
Laser Printer / 50-75 / 100-150
Newspaper / 85-100 / 170-200
Glossy, coated magazine / 150-200 / 300-400
Uncoated paper (newsletters, stationery, book interiors) / 133-150 / 266-300
Websites / No LPI requirements / 72
Graphic File Formats and Their Usage
Many people today are familiar with the hundreds of types of files available. PNG, JPEG, and GIF formats are most often used to display images on the Internet. They are separated into two main families of: raster and vector. Raster formats store images as bitmaps. Vector image formats contain a geometric description which can be rendered smoothly at any desired display size. PNG, JPEG, GIF, TIFF and BMP are raster formats. CGM and SVG are vector formats.
* JPEG is a highly compressed, small file format and it maintains the image’s quality. Sometimes though, a JPEG file can become degraded if it’s repeatedly edited and re-saved. Adobe pdf file format uses JPEG compression.
* TIFF image format is not widely supported by web browsers. TIFF remains widely accepted as a photograph file standard in the printing business.
* PNG (Portable Network Graphics) file format was created as the free, open-source successor to the GIF. The PNG file format supports truecolor (16 million colors) while the GIF supports only 256 colors. The PNG file excels when the image has large, uniformly colored areas.
* GIF (Graphics Interchange Format) is limited to an 8-bit palette, or 256 colors. This makes the GIF format suitable for storing graphics with relatively few colors such as simple diagrams, shapes, logos and cartoon style images. The GIF format supports animation and is still widely used to provide image animation effects.
* BMP file format (Windows bitmap) handles graphics files within the Microsoft Windows OS. Typically, BMP files are uncompressed, hence they are large; the advantage is their simplicity and wide acceptance in Windows programs.
A graphic artist is intimately family with all these file formats and knows the best one to use in each application, be it printing your business cards, a brochure, your website, or an marketing material your company requires. While desktop publishing from your home office is always available, to get that special oomph that sings “Professionally Created” is more than likely the best way to represent you, your company, and your brand.
Karen Saunders is the author of “Turn Eye Appeal into Buy Appeal: How to easily transform your marketing pieces into dazzling, persuasive sales tools!” Learn about her book and get free instant access to her eCourse: “5 Deadly Design Mistakes that Could Kill a Sale and How to Avoid Them” and audio class: “Put the Bling Into Your Brand” at http://www.macgraphics.net or call 888-796-7300.
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