Sep 04
2008You might find yourself wondering what image file formats Photoshop will open or save in. What are the advantages or disadvantages of each?
Simply put, Photoshop has the ability to open and save a variety of graphic files. Let’s take a look at the more popular ones.
One thing to remember is that when you open an image file other than a Photoshop one, the image will default to the background layer.
1) .psd, .pdd, .eps - Photoshop File
These are Photoshop files. This format saves all of the information found in all of the layers. This format works best if you are going to continue to work with a picture. A downside can be that the file size may be quite large. You should save your work in the most recent Photoshop format available. An example would be is you have Photoshop CS and are sent a Photoshop 7 file, you would want to save it as a Photoshop CS file to maintain any elements that may not be supported in Photoshop 7.
2) .jpg, .jpeg .jpe
This format compresses images in a way that information such as color subtleties and other details are lost. You can select to what extreme you want to compress the image. This is the most suitable format for use on the web. Consists of small file sizes and millions of colors.
3) tif, .tiff
Early scanners typically used this format. It will generate high quality images, but very large files making it inappropriate for use on the web.
.gif
This format is one of the most popular for web graphics as it loads quickly and has an 8 bit format (256 colors max.). It has potential for transparent color and animation.
5) .png
This is a new format for use on the web that is intended to replace both gif and jpeg with its ability to compress, have millions of colors, and support transparencies. It compresses differently from jpeg, and has advanced possibilities, such as alpha channel (opaque or partly transparent colors). The only problem is that Internet Explorer does not support this format. In 8 bit (256 colors) mode it compresses better than gif.
.bmp
This is a windows bitmapped image. It is used by Microsoft Windows applications and provides good quality but large file size. Not for use on the web.
7) .wmf
Windows MetaFile. Useful for clipart, and can be used to make large area, small sized background files.
.pcx
This older format is for general purpose and is basically obsolete now. Not for use on the web.
9) .psp
This format is an internal format for Paint Shop Pro and is useful if you need to swap files between these two applications.
10) .pcd
Kodak PhotoCD format, used with Photo Developing but most photo processors will save your photos as jpegs if you ask.
Portable Document File. Adobe’s file system that allows electronic cross platform sharing of documents.
So which is the best format for web graphicsgif or jpeg?
Easy way to remember is that gifs are typically used for drawings and jpegs for photos. Use gifs for diagrams, illustrations, line drawings and images with large areas of flat color. Jpeg should be used for photographs and images with continuous color tones. While the jpeg has an excellent compression rate, the compression lowers the quality of the image so try out some of the tools in Image Ready to find the optimal quality/file size. The gif format in comparison has a smaller file size but a limited range of colors.
