Adobe Photoshop's native file format is ".psd". This is the only format which supports all of Photoshop's features: layers, layer masks, layer comps, etc. If you have used these features in creating your final artwork, it is always a good idea to retain the ".psd" version and use File - Save As to export your work in any other format.
If you are exporting images from Photoshop, you will normally either be producing either print or web graphics. Print graphics are saved in the CMYK colour space while web graphics remain in Photoshop's native colour space: RGB. With print graphics the focus is on quality, while the main talent of web graphics formats is file compression.
TIFF (Tagged Image File Format) and the CMYK colour space are the standard when exporting work for print. Although the TIFF format is capable of preserving layers, best practice is to make sure that you flatten the image by choosing Layers - Flatten Image before exporting. EPS (Encapsulated PostScript) is another option for exporting files for print. However, this option is now normally reserved for files that contain one or more spot colours.
The two main formats used for exporting web graphics are GIF (Graphic Interchange Format) and JPEG (Joint Photographic Experts Group). The GIF format compresses files by reducing the number of colours in an image. This makes the format ideal for exporting images that contain flat colour such as logos, charts and symbols. If photographs or images containing smooth transitions of colour are saved in GIF format, posterization and banding will normally occur. This is where, instead of seeing all the colours that were in the image, we see simplified clumps or bands of colour.
The JPEG format compresses images by dividing the image into blocks of 8 x 8 pixels and locating redundant information within these blocks and rewriting the information in a simplified manner which requires less data storage. The fact that the human eye does not detect slight changes in colour means that pixels which have very similar colour values can be treated as being identical. When saving an image in the JPEG format, Photoshop allows you to specify the degree of compression. Naturally, there is always some loss of quality, so it is never a good idea to open a JPEG, make changes to it and then resave it. It is always better to fall back on the original PSD file if changes need to be made.
If you are exporting images from Photoshop, you will normally either be producing either print or web graphics. Print graphics are saved in the CMYK colour space while web graphics remain in Photoshop's native colour space: RGB. With print graphics the focus is on quality, while the main talent of web graphics formats is file compression.
TIFF (Tagged Image File Format) and the CMYK colour space are the standard when exporting work for print. Although the TIFF format is capable of preserving layers, best practice is to make sure that you flatten the image by choosing Layers - Flatten Image before exporting. EPS (Encapsulated PostScript) is another option for exporting files for print. However, this option is now normally reserved for files that contain one or more spot colours.
The two main formats used for exporting web graphics are GIF (Graphic Interchange Format) and JPEG (Joint Photographic Experts Group). The GIF format compresses files by reducing the number of colours in an image. This makes the format ideal for exporting images that contain flat colour such as logos, charts and symbols. If photographs or images containing smooth transitions of colour are saved in GIF format, posterization and banding will normally occur. This is where, instead of seeing all the colours that were in the image, we see simplified clumps or bands of colour.
The JPEG format compresses images by dividing the image into blocks of 8 x 8 pixels and locating redundant information within these blocks and rewriting the information in a simplified manner which requires less data storage. The fact that the human eye does not detect slight changes in colour means that pixels which have very similar colour values can be treated as being identical. When saving an image in the JPEG format, Photoshop allows you to specify the degree of compression. Naturally, there is always some loss of quality, so it is never a good idea to open a JPEG, make changes to it and then resave it. It is always better to fall back on the original PSD file if changes need to be made.
About the Author:
The writer of this article runs Adobe Photoshop CS4 training courses and InDesign training throughout the UK.
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