File Types, Sizes & Dots Per Inch (dpi)

Best practices applied to Photoshop file formats when creating media-specific documents.

Bit Depth is the number of colors your image contains:• 24 bit = millions of colors• 16 bit = thousands of

colors• 8 bit = 256 colors• 4 bit = 16 colors

Data Compression is a process of encoding info with fewer bits:• Lossless = reversible with more algorithmic data• Lossy = loss of data

Adobe PhotoshopFile Formats

Adobe PhotoshopFile Formats.psd PhotoShop Document

dpi 300 pixelswork large!work in layers

Adobe PhotoshopFile Formats.jpg Joint Photographic Expert Group

dpi depends on purposedetail 300 dpiprint >150 dpiscreen 72 dpi

JPG is a "lossy" compression, resulting in data loss. Used for photographs and images with continuous tones and large gradients. Do not save/edit in jpg!

Image: From the department of unsourced photographic Internet literalisms

Adobe PhotoshopFile Formats.gif Graphical Interface Format

dpi 72 pixels

Animated Static

Image: Watt Curve by Claudio Rocchini

GIF supports images that are 8-bit (256 colors) or less. Use GIFs for illustrations, clip art, and images without gradients.

Adobe PhotoshopFile Formats.png Portable Network Graphics

dpi 72 pixels

PNG is an improvement on GIF - with gradients and transparencies in "lossless" format - Designed for RGB color palettes, not print.

Adobe PhotoshopFile Formats.tiff Tagged Information File Format

dpi depends on purposeArchive >300 dpi

TIFF is an adaptable file format for handling images and data within a single "lossless" file or no compression at all. This format is useful for image archiving - can include header tags and vector-based information.

Adobe PhotoshopFile Formats.pdf Portable Document Format

dpi depends on purposehighly customizable

PDF is an open standard for document exchange with encapsulated information. PDFs can store a fixed-layout document that includes the text, fonts, images, vector graphics and true graphic transparency.

Adobe PhotoshopFile Formats - Summary

.psd PhotoShop Document

.jpg Joint Photographic Expert Group

.gif Graphical Interface Format

.png Portable Network Graphics

.tiff Tagged Information File Format

.pdf Portable Document Format

Consider…

Bit Depth Data Compression

DPI (dots per inch) Vector graphics