Fileformats

What’s the best file format for your image?

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For storage, layered images

.PSD (Photoshop Draw)

pros

* lossless
* supports Layers
* 4Gb limit on file size

cons

– a number of programs won’t read PSD.

.TIF (TIFF – Tagged-Image File Format)

pros

* also lossless.
* also supports layers (from v6 onwards).
* also 4GB limt on file size
+ open standard – universally supported in native format

cons

– native TIFF files can be quite a bit larger than PSD
– compressed TIFF LZW files are similar in size to PSD files but not universally accepted

There is no loss of quality with either format, nor with converting between the two.

By the way PSD is a special adobe formatted TIFF.
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For rendered images

.JPG (JPEG – Joint Photographic Experts Group)

pros

+ small filesize
+ color space definition (supports RGB, Grayscale & CMYK)
+ supports EXIF data
* supports progressive images

cons

– lossy compression
– supports 8bit only (not able to 16bit ProPhotoRGB)
* doesn’t supports LAB

The JPEG format, with its support for 16.7 million colors, is primarily intended for photographic images. The internal compression algorithm of the JPEG format, unlike the GIF format, actually throws out information. Depending on what settings you use, the thrown out data may or may not be visible to the eye. Once you lower the quality of an image, and save it, the extra data cannot be regained so be sure to save the original.

.PNG (Portable Network Graphics)

pros
+ lossless compression
+ supports up to 24bit (able to 16bit ProPhotoRGB)
* supports progressive images

cons
– supports RGB & Grayscale only (doesn’t supports CMYK)
– doesn’t supports EXIF data
* doesn’t supports LAB

The newest file format that’s widely supported by the Web is PNG (pronounced Ping). PNG was developed to surpass the limitations of GIFs, and as a means by which developers can avoid having to worry about the patent licenses associated with other formats. PNG was designed to offer the main features of the GIF format, including streaming and progressive file formats. It also provides greater depth of color, catering to images up to 24 bit in color.

PNG was designed for transferring images on the Internet, not professional graphics, and so does not support other color spaces (such as CMYK).

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If you want to render images in 16bit ProPhotoRGB, use PNG, otherwise use JPG (with maximum quality).

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