Photoshop File Extensions: Ever wonder what all of those extensions are for?
NOTES:
What is a raster graphic/image? TechTerms.com defines it as “Most images you see on your computer screen are raster graphics. Pictures found on the Web and photos you import from your digital camera are raster graphics. They are made up of grid of pixels, commonly referred to as a bitmap. The larger the image, the more disk space the image file will take up.”
· Photoshop (.psd/.pdd): This is the base file extension for Photoshop files. It allows you to edit the layers, masks, filters, and other special effects of the file.
· Large Document Format (.psb): This is the file extension you would use for a .psd that is too large for the normal .psd file size limit (30,000 x 30,000 pixels). A .psb can save an image up to 300,000 x 300,000 pixels.
· BMP (.bmp/.rle/.dib): This should be used for Bitmaps (images with a grid of pixels; most images on computers) that are uncompressed raster images (has a grid of pixels and uses the area of all of the pixels). These images have a file header (bitmap identifier, file size, width, height, color options, and bitmap data starting point) and bitmap pixels, each with a different color. There might be different levels of color depth depending on what the “bits per pixel” is defined as in the file header.
· CompuServe GIF (.gif): This stands for “Graphics Interchange Format” and is used as an alternative to a JPEG to save a flattened image. However, the color palette (all the colors used in the image) is restricted to 256 color indexes. CompuServe is the company who first introduced this file format. GIF files can also be saved as “animated GIFs” which are simple animations that are frame-based. The pixels in the frames can be transparent or opaque, but are unable to blend.
· DICOM (.dcm/.dc3/.dic): This stands for “Digital Imaging & Communications in Medicine” and is the standard for medical images like MRIs, CT scans, & Ultrasounds. These images also contain patient specific identification information that links the patient to the image.
· Photoshop EPS (.eps): This stands for “Encapsulated PostScript” and contains 2D vector graphics, bitmap images, and text. These vectors can be used to print stickers, stencils, etc.
· Photoshop DCS 1.0/2.0 (.eps): This stands for “Desktop Color Separation” and is used for printing color separations. The difference between 1.0 & 2.0 is that 2.0 supports greyscale & extra color channels.
· IFF Format (.iff/.tdi): This stands for “Interchange File Format” and is made of data sections (“chunks”) that contain text, numerical data, or raw data (minimally processed data from an image sensor; camera, image scanner, etc). There are 3 main chunks: FORM (specifies the file format), LIST (contains the file properties), & CAT (rest of data).
· JPEG (.jpg/.jpeg/.jpe): This is a standard picture formats. You can save images such as a .psd as a JPEG to save hard drive space. It would compress/flatten your Photoshop file into one layer (bitmap); however, it would experience lossy compression. JPEGs are most useful for real life pictures from a camera such as landscapes.
· JPEG 2000 (.jpf/.jpx/.jp2/.j2c/.j2k/jpc): This is just like a JPEG only image transparency and additional metadata is supported.
· PCX (.pcx): This is a raster image format that uses RLE encoding. It can be used by some printers and scanning machines.
· Photoshop PDF (.pdf/.pdp): This is a file format that can contain text, images, etc. that looks exactly how it would look if you printed it. It is also optimized for use over multiple platforms, as indicated by “Portable Document Format.”
· Photoshop Raw (.raw): This is simply raw image data that is taken off of a camera. It is uncompressed.
· Pixar (.pxr): Developed by PixarTM in 1986, this file extension is an uncompressed raster image that supports RGB and Greyscale colors in an 8-bit channel. It has been used for computer animation and medical imaging.
· PNG (.png): Similar to a JPEG, PNGs are a standard image format. They are commonly used on the web because in has an 8-bit transparency channel that allows fading between opaque and transparent pixels.
· Portable Bit Map (.pbm/.pgm/.ppm/.pnm/.pfm/.pam): This is the simplest of image file types. It contains a 1-bit black & white image formatted in binary code where 1=black & 0=white.
· Scitex CT (.sct): This is considered a “Continuous Tone File” which means it is a CMYK or Greyscale raster image that is saved in an uncompressed format so that full quality is maintained.
· Targa (.tga/.vda/.icb/.vst): This is a raster graphic that supports up to 24 bits per pixel with an 8-bit alpha channel used for storing 3D video game graphics. It also includes a compressed, scaled-down copy used as a thumbnail.
· TIFF (.tif/.tiff): This stores raster & vector images compressed in high quality. It also has the capability to store multiple layers.
*TIP: you can search what file extensions mean at http://fileinfo.com/
another good site is http://www.creativepro.com/article/graphics-fundamentals-understanding-photoshop-file-formats-
What is a raster graphic/image? TechTerms.com defines it as “Most images you see on your computer screen are raster graphics. Pictures found on the Web and photos you import from your digital camera are raster graphics. They are made up of grid of pixels, commonly referred to as a bitmap. The larger the image, the more disk space the image file will take up.”
· Photoshop (.psd/.pdd): This is the base file extension for Photoshop files. It allows you to edit the layers, masks, filters, and other special effects of the file.
· Large Document Format (.psb): This is the file extension you would use for a .psd that is too large for the normal .psd file size limit (30,000 x 30,000 pixels). A .psb can save an image up to 300,000 x 300,000 pixels.
· BMP (.bmp/.rle/.dib): This should be used for Bitmaps (images with a grid of pixels; most images on computers) that are uncompressed raster images (has a grid of pixels and uses the area of all of the pixels). These images have a file header (bitmap identifier, file size, width, height, color options, and bitmap data starting point) and bitmap pixels, each with a different color. There might be different levels of color depth depending on what the “bits per pixel” is defined as in the file header.
· CompuServe GIF (.gif): This stands for “Graphics Interchange Format” and is used as an alternative to a JPEG to save a flattened image. However, the color palette (all the colors used in the image) is restricted to 256 color indexes. CompuServe is the company who first introduced this file format. GIF files can also be saved as “animated GIFs” which are simple animations that are frame-based. The pixels in the frames can be transparent or opaque, but are unable to blend.
· DICOM (.dcm/.dc3/.dic): This stands for “Digital Imaging & Communications in Medicine” and is the standard for medical images like MRIs, CT scans, & Ultrasounds. These images also contain patient specific identification information that links the patient to the image.
· Photoshop EPS (.eps): This stands for “Encapsulated PostScript” and contains 2D vector graphics, bitmap images, and text. These vectors can be used to print stickers, stencils, etc.
· Photoshop DCS 1.0/2.0 (.eps): This stands for “Desktop Color Separation” and is used for printing color separations. The difference between 1.0 & 2.0 is that 2.0 supports greyscale & extra color channels.
· IFF Format (.iff/.tdi): This stands for “Interchange File Format” and is made of data sections (“chunks”) that contain text, numerical data, or raw data (minimally processed data from an image sensor; camera, image scanner, etc). There are 3 main chunks: FORM (specifies the file format), LIST (contains the file properties), & CAT (rest of data).
· JPEG (.jpg/.jpeg/.jpe): This is a standard picture formats. You can save images such as a .psd as a JPEG to save hard drive space. It would compress/flatten your Photoshop file into one layer (bitmap); however, it would experience lossy compression. JPEGs are most useful for real life pictures from a camera such as landscapes.
· JPEG 2000 (.jpf/.jpx/.jp2/.j2c/.j2k/jpc): This is just like a JPEG only image transparency and additional metadata is supported.
· PCX (.pcx): This is a raster image format that uses RLE encoding. It can be used by some printers and scanning machines.
· Photoshop PDF (.pdf/.pdp): This is a file format that can contain text, images, etc. that looks exactly how it would look if you printed it. It is also optimized for use over multiple platforms, as indicated by “Portable Document Format.”
· Photoshop Raw (.raw): This is simply raw image data that is taken off of a camera. It is uncompressed.
· Pixar (.pxr): Developed by PixarTM in 1986, this file extension is an uncompressed raster image that supports RGB and Greyscale colors in an 8-bit channel. It has been used for computer animation and medical imaging.
· PNG (.png): Similar to a JPEG, PNGs are a standard image format. They are commonly used on the web because in has an 8-bit transparency channel that allows fading between opaque and transparent pixels.
· Portable Bit Map (.pbm/.pgm/.ppm/.pnm/.pfm/.pam): This is the simplest of image file types. It contains a 1-bit black & white image formatted in binary code where 1=black & 0=white.
· Scitex CT (.sct): This is considered a “Continuous Tone File” which means it is a CMYK or Greyscale raster image that is saved in an uncompressed format so that full quality is maintained.
· Targa (.tga/.vda/.icb/.vst): This is a raster graphic that supports up to 24 bits per pixel with an 8-bit alpha channel used for storing 3D video game graphics. It also includes a compressed, scaled-down copy used as a thumbnail.
· TIFF (.tif/.tiff): This stores raster & vector images compressed in high quality. It also has the capability to store multiple layers.
*TIP: you can search what file extensions mean at http://fileinfo.com/
another good site is http://www.creativepro.com/article/graphics-fundamentals-understanding-photoshop-file-formats-