Standards Based Development

Adobe Photoshop Color File Format (.aco)

.aco Files

In Adobe Photoshop, the active swatches palette can be saved to, or loaded from, an aco (Adobe COlor) file.

• In Mac OS X and Windows, the file extension of an aco file is '.aco'.
• In Mac OS 9 and below, the file type is '8BCO'.

Two versions of the palette format exist:

• A version 1 palette lists the coordinates of each color in a specified color space.
• A version 2 palette lists both the coordinates and the name of each color.
  • The name is what you see displayed as a rollover when the mouse cursor hovers over the color in the palette.

When saving an aco file, Photoshop releases prior to 7.0 wrote only a version 1 palette. When loading an aco file today, these old versions of Photoshop read the version 1 palette and ignore any version 2 palette that may be present.

Photoshop 7.0 writes a version 1 palette followed by a version 2 palette. When loading an aco file, it reads the version 2 palette, if present. Otherwise, it reads the version 1 palette.

aco Palettes

Each palette in an aco file is a series of 16-bit big-endian words.

Macs are big-endian. On Wintel machines, it is necessary to swap the bytes of each 16-bit word.

The palette begins with a two-word header:

The header is followed by nc color specs. In a version 1 ACO file, each color spec occupies five words:

In a version 2 ACO file, those five words are followed by the color name in the following format:

Example: The name "A2" appears as hexadecimal 00 03 41 62 00 (ASCII "A2" = 4162; len=2, len+1=3).

Color Specs

The table below describes the process for converting a color spec (three or four 16-bit values) to its Photoshop color picker equivalent (three or four 8-bit values).

Example:

Interpretation:

1. The range of values for this 16-bit word is 0 to 65535, inclusive.
   • When the range begins with 0, the word is an unsigned int.
   • When the range begins with a negative number, the word is a signed int.
2. The color coordinate H is determined by this word. In the Photoshop color picker, H ranges from 0° inclusive to 360° exclusive. To calculate a value of H in the color picker's range, divide w by 182.04.
   • The mathematical notation [...] denotes a closed interval that includes the values adjacent to the brackets.
   • The notation [...) denotes a half-open interval that excludes the value adjacent to the parenthesis.
   • The Photoshop color picker rounds fractions down to whole numbers.

In addition to the above, Photoshop 7.0 can read color spaces #13 and #15, however, they have not been identified.

Photoshop 7.0 can not read color spaces #3-6, #10-12, #14. Plug-ins may be available that can read these and other color spaces.

References and Resources

• Reverse-Engineering of the Adobe Color File Format by Chris Berry.
• Adobe Photoshop File Formats Specification by Adobe Systems Incorporated and Thomas Knoll.

Adobe Color Book Files

Adobe Color Books ).acb) contain color catalog data files; Photoshop's Color Picker comes with a Custom Colors dialog option, which offers a variety of colors from several industry-standard color catalogs.

References and Resources

• Adobe Color Book File Format Specification

Adobe Color Book File Format Specification

ACB2XML - Convert Photoshop Adobe Color Books to xml

is a command-line Windows application that extracts color data from Adobe Color Books and generates it back into xml.

For information about the format of Adobe Color Book (ACB) files, see: The Unofficial Photoshop Color Book File Format Specification by Ates Goral.

This page was contributed to the public domain by Larry Tesler, 9-Oct-2004.

.aco Adobe COlor Book Files

The color catalog data comes from Adobe Color Book files. These file have the .ACB file extension on Windows and reside inside the ".../Presets/Color Book" folder in a typical installation.

.ase Adobe Swatch Exchange

Adobe CS6: How to Save and Import Adobe Swatch Exchange (.ase) Files

Working with Adobe Swatch Exchange files in Fireworks, Illustrator, Photoshop and InDesign is actually very easy and very similar between each of these products. So we will run you through them all together and just point any variations between these products as we go.

1. Step one: In the swatches panel of either Illustrator, Photoshop, Fireworks or Indesign select the colors you wish to include in your custom swatch file.
2. Step two: Open up the Swatches palette or Swatches panel menu and select:
   • Photoshop CS6 -> Save Swatches for Exchange
   • Fireworks CS6 -> Save Swatches
   • Illustrator CS6 -> Save Swatch Library as ASE
   • InDesign CS6 -> Save Swatches

   The palette or panel menu should look like this up in the right hand corner of that panel You NEed A Goddamhn Image Moron:

3. Step Three: save the swatch from the save menu, ensuring that the file type is set to .ase.

Note: Adobe's Kuler tool permits color swatch saving, which are meant to be then imported from Kuler's site to your design software.

Color Swatch CS Family Sublteties

The process of opening up a Color Swatch has subtle differences across four cs products; Initially, in the desired product, open Swatches panel/palette, and from there open the panel/palette menu. Depending on which product you are using, select one for the four options below:

• Photoshop CS6: Load Swatches … OR Replace Swatches
• Fireworks CS6: Replace Swatches… OR Add Swatches
• Illustrator CS6: Open Swatch Library … >> Other Library
• InDesign CS6: Load Swatches

Then simply locate the desired .ase and open it.

Note: in Illustrator, you must change the desired file type to .ase to view, as well as to select it; not changing the file extension will result in the file not being able to be found.