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Photoshop Files and Formats |
Photoshop Files and Formats
By Shaun Pearce
People often ask me: What image file formats will Photoshop open or save
in? What are the advantages/disadvantages?
Photoshop has the capability to open and save many different graphic
files. Here are some of the most popular ones.
Note: When you open an image file other than a Photoshop one, that image
will default to the background layer.
.psd, .pdd, .eps
Photoshop File. This format preserves the information in all the layers.
If you're going to continue working with a picture, this is the best
format to use. File size can be quite large, however. Note: It is
advisable to save your work in the most up to date Photoshop format
available. For example: if you have Photoshop CS2 and are sent a
Photoshop 7 file, you should save it as a Photoshop CS2 file to preserve
any elements that may not be supported by Photoshop 7.
.jpg, .jpeg .jpe
This format compresses the images, so that information (details and
colour subtleties) are lost. You can choose how much you want to
compress the image. Good format for use on the web. Small file sizes.
Millions of colours.
tif, .tiff
Common in use with early scanners. Will produce high quality images, but
very large files. Not for use on the web.
.gif
Pronounced both "Gif" and "Jif", this file is one of the most popular
for web graphics as it loads quickly. 8 bit format (256 colours max.).
It has possibilities for transparent colour and animation.
.png
New format for use on the web that is intended to replace both gif and
jpeg. Compressed, millions of colours, transparencies. It compress in a
different way than jpeg, and has advanced possibilities, such as alpha
channel (opaque or partly transparent colours). The only trouble is:
Internet Explorer doesn't support these! In 8 bit (256 colours) mode it
compresses better than gif.
.bmp
Windows bitmapped image. Used by Microsoft Windows applications. Good
quality, large file size. Not for use on the web.
.wmf
Windows MetaFile. Useful for clipart, and can be used to make large
area, small sized background files.
.pcx
Older general purpose format. Practically obsolete now. Not for use on
the web.
.psp
Internal format for Paint Shop Pro, useful if you want to swap files
between these two applications.
.pcd
Kodak PhotoCD format, used with Photo Developing - although most photo
processors will save your photos as jpegs if you ask them to.
.pdf
Portable Document File. Adobe's file system that allows electronic cross
platform sharing of documents.
So what's the best format for web graphics: gif or jpeg?
The general rule of thumb is to use gifs for diagrams, line drawings,
illustrations, and images that contain large areas of flat colour, and
jpegs for photographs and images with continuous colour tones. The jpeg
format has a very good compression rate, but compression reduces the
quality of the image, so it's best to experiment with the tools in Image
Ready until you have the optimal quality/file size. The gif format, on
the other hand, has a smaller file size - but a limited range of colours.
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Shaun Pearce is a writer and video maker.
His latest production, "Photoshop Master", is an interactive video
tutorial. It shows you how to get the most from Photoshop, and can be
downloaded from http://www.learnphotoshopfast.com.
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This article is © copyright Shaun Pearce 2008 and may be reproduced in
magazines, eZines, and web pages. There is no charge, provided the
contact information box above is unaltered.
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