File Extension ACT

  • Full name
    Adobe Photoshop/Illustrator Color Table
  • Developer
  • Popularity
Have you encountered a problem with a ACT file? Don’t you know which program opens a file with this extension? You will find all the information you need about working with a ACT file here. In the further part of this page we have added a list of programs that should open your ACT file. It is enough you choose a proper application for your operating system, download and install it.


ACT files are Adobe Color Table files, which are color tables for the image editing software Adobe Photoshop and the vector graphics software Fireworks. Act files contain so-called indexed colors and serve as CLUT (Color Lookup Table).

For example, color table files are used in webpage image preparation to store images in web-safe colors. For example, if you choose 'save for internet', you can load an ACT color table to colorize the image.

ACT files can be created just like aco swatches create files. You can access the color tables in Photoshop by clicking on the little arrow in the Swatches window. Photoshop also offers a few included color tables, including Windows, Mac or Black and White.

Note, however, that indexed colors are only supported by gif and png-8, but not by jpeg or bmp.

Programs which can open a ACT file

How to open a ACT file? Advice and guidance

Absolutely most often appearing reason that prevents you from opening the ACT file is the lack of a proper application to support it in your operating system. It is notably the first thing you need to address. When one of the programs to support a ACT file from the list is already installed, you can try to rerun the file. The system should display a message asking you to choose a primary application to support ACT files. At this point we are looking for disk space where the application was installed in and we can link it with a ACT file. Since then, our operating system will use the selected program to support all ACT files.

Other issues

Despite the described problem with ACT there may be many more problems. If the existing operations were not effective, get involved with the following matters:

- verify that the ACT file is not damaged and that it has been downloaded or copied in whole
- verify that the file has a file extension that has not been intentionally changed (for example, if it do not contain other information than its extension suggests)
- make sure again whether the ACT file type is linked in the operating system with a proper program
- make sure that the file is not infected with a virus and you have up to date software and drivers.

Similar extensions