CPG File

What are CPG files and how to open them

Are you having problems opening a CPG file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your CPG files.

What is a CPG file?

CPG files have multiple uses, and ComicStudio Page is one of them. Read more about the other uses further down the page.

ComicStudio Page File

ComicStudio is a Japanese drawing program mainly used by illustrators, manga artists, and animation studios. It saves page layouts in files using the CPG file extension.

How to open CPG files

We have identified two CPG openers that are compatible with this specific type of CPG file.

Programs that open ComicStudio Page files

Last updated: September 2, 2026

All known file formats using extension .CPG

While ComicStudio Page File is a popular type of CPG-file, we know of 5 different uses of the .CPG file extension. Different software may use files with the same extension for different types of data.

Clip Studio Page

Clip Studio Page format is a graphic page file originally used by the Japanese programs ComicStudio / MangaStudio (also known as Clip Studio Paint's predecessors) to store a single comic or illustration page. It captures all the layer data - including raster layers, vector layers, text layers, tone, panel and frame ruler folders - needed to preserve the full editable content of a page for later drawing, editing, printing or conversion.

Files in this format are created by ComicStudio / MangaStudio, and more recent versions of Clip Studio Paint (PRO and EX) offer the ability to import them. Import settings allow the user to flatten or combine all layers, enable anti-aliasing for vector layers, or convert vector layers into raster layers depending on user preference. Upon import into Clip Studio Paint, some layer types may lose editability or change appearance depending on how they are converted or rasterized.

Page files use the CPG extension and are structured so that each page has not only the main page file, but often a matching folder of layer files. For full working with the page (especially opening or editing layers), the page file and its layer folder must remain together. When opening these files in MangaStudio 5 or Clip Studio Paint, users may convert and then save the result in Clip Studio's native clip format if desired. Important metadata such as layer organization, layer types, bitmap depth and text content exist in the page file and (when present) in auxiliary layer files.

The format's internal signature includes the ASCII header "GPSC" at offset 0, and the presence of internal names for components and layer files such as "0001.CFL", "0001.CGR", "LAYER", "0001.CTB", among others.

While we have not verified the apps ourselves yet, our users have suggested eight different CPG openers which you will find listed below.

Cool Page Project

Cool Page Project files store all design information for a website project created with Cool Page, a drag-and-drop WYSIWYG webpage editor produced by 3Dize. These project files preserve the layout of objects such as text blocks, images, backgrounds, links, animations, and other page elements; allow editing and previewing in Cool Page; and enable the finished project to be exported into HTML for viewing in Web browsers. The editor was last updated in 2002, with version 2.72 being the final release, running on Windows systems up through Windows XP.

Cool Page writes project files in a proprietary binary format. The files are not plain text and cannot be reliably opened or modified by generic text or code editors. Within Cool Page, users build up a project and save it with all its page layout objects, object properties (positions, sizes, styles, behaviors), and possibly linked resource files. When the design is complete, Cool Page exports the project as standard HTML and associated resource files for publishing.

The internal structure of a project file begins with the ASCII header signature ".CoolPageFile" at offset 0. Another identifying string "PageBackground" appears at offset 26.

FontLab Codepage Definition

FontLab Codepage Definition format is used by the FontLab software to define how single-byte character codes map to Unicode codepoints. These definition files specify "codepages" that FontLab shows in its Codepage popup menus so users can view, reencode, or lay out glyphs according to different legacy or custom mapping schemes.

These files are created and used by FontLab Studio, FontLab VI, TypeTool, TransType and related FontLab applications. They are plain text files stored in special "Codepage" folders within the application's internal resources or in user/custom data folders. To add new mappings or change existing ones, the file is edited in a text editor, then placed into the Codepage folder; FontLab must be restarted for changes to appear.

Each file starts with a first line identifying it as a valid FontLab codepage definition, using a signature like "%%FONTLAB CODEPAGE: 0xFFFF; <Name>" (or in older versions "%%FONTLAB STUDIO CODEPAGE: …"). The second line names the group under which the codepage appears in menus. Following lines map codes in the 0 - 255 range to Unicode codepoints (0 - 65535), using numbers in decimal or hexadecimal (prefixed "0x"). A special Unicode codepoint value (0xFFFF) denotes codes that do not map to any character.

The file begins with a specific ASCII header signature at offset zero, for example "%%FONTLABCODEPAGE:0x" followed by other content, which serves both to name the codepage and to signal to FontLab that this is a proper codepage definition file.

Manga Studio Page

Manga Studio Page is a page file format created by the older ComicStudio / MangaStudio applications (versions 3 and 4) to store a single comic‐page with all its contents such as layers, vector and raster artwork, text balloons, screen tones, rulers and other drawing aids. It preserves the structure of the page so that it can be edited or imported: for example Clip Studio Paint (versions PRO and EX) can open these page files, converting them into its own internal document format while retaining as many layers and settings as possible.

This format is produced when a user saves or exports a page within MangaStudio / ComicStudio. After importing into Clip Studio Paint, the artwork can be edited further or saved in the newer native format (such as .clip). Pages typically retain layers, vector/raster distinctions, text, balloons, tones and other analogues of the source file's components - although certain features (e.g. some layer types, guides, ruler layers, or text styles defined in Story-Edit Memo) may not import perfectly or remain editable.

Files begin with a four-byte ASCII signature "GPSC" at offset 0, and contain recognizable chunk or field names such as "LAYER", ".CTB", ".CRU", ".CRA" in their internal data.

Various apps that use files with this extension

These apps are known to open certain types of CPG files. Remember, different programs may use CPG files for different purposes, so you may need to try out a few of them to be able to open your specific file.

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