This article describes two file formats that use the PCT file extension. It also explains how they are used and how to open or convert them on your computer.
How to File Your Patent Anywhere in the World Using a PCT Application
A file with the PCT file extension is a Macintosh PICT Image, and was the default file format for the (now discontinued) QuickDraw Mac program. Some applications still use the format, but PDF has all but replaced it.
The image data in one of these image files can be in the original PICT 1 format or in the PICT 2 format introduced in Color QuickDraw. The former can store eight colors, while the second and newer format supports thousands of colors.
Depending on the application used to create the image, it may have either the PCT or PICT file extension, but both have the same format.
