Base image--The image of the site.
dpi--Dots Per Inch or dpi relates to the density of dots that can be printed in one linear inch on a sheet of paper.
.gif--Graphic Interchange Format, .bmp--Bit Mapped Graphics and .raw: These are all considered uncompressed formats and are generally acceptable as extensions for photography and scanning.
.jpeg--Joint Photographic Experts Group. .jpeg is one of the most commonly used extensions because it creates a relatively small file size, and it can be imported into other programs such as AutoCAD, SketchUp, and InDesign. The only disadvantage is that it groups very similar colored pixels into a single color, which helps make such a small file size but causes what is known as lossy compression. It loses the original color sequence of pixels, but in most cases this is not noticeable. The problem is when the image is saved repeatedly-each time the image is saved, it groups more and more similar colors together. The best way to minimize the effect of lossy compression is to make sure that, after hitting Save As, you set the Quality under Image Options to Max. or 12 in the .jpeg Options Box.
.pdf--Portable Document Format or the Adobe Acrobat Extension. This is primarily for viewing and e-mailing because saving with this extension creates a relatively small file size.
ppi--Pixels Per Inch or ppi relates to the number of pixel boxes that occur in one horizontal or vertical inch of your computer display.
.psd--Photoshop Document Extension. This is the default extension when any image has been altered in Photoshop. It allows you to keep your layers, styles, channels and filters in an uncompressed format so you do not lose any information.
Source images--The images used for redesigning the site.
.tiff--Tagged Image File Format. .tiffs are an uncompressed format. The .tiff format is very popular for saving original photos or scans. Because it records the data pixel by pixel, .tiff files do not lose or group information as do .jpeg, but a huge file size is created. You might consider scanning or saving your originals as .tiff but resaving them as .jpeg to work with. That way you always have an excellent-quality original to go back to.
By Professor Ashley Calabria
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|Title Annotation:||CHAPTER 4: Photoshop Imaging|
|Publication:||Computer Graphics for Landscape Architects, An Introduction|
|Date:||Jan 1, 2009|
|Previous Article:||Saving and plotting.|
|Next Article:||Chapter 5: InDesign.|