EXR to PCX Converter

Encoding: the EXR uses none, RLE, ZIP, PIZ, PXR24, B44 or DWA, chosen per file; PCX uses byte-wise run-length encoding, and the download is a run-length encoded PCX: 8-bit indexed when the image has 256 colours or fewer, otherwise 24-bit RGB.

Bit depth: 16-bit half or 32-bit floating point per channel in the EXR; PCX allows 1, 2, 4 or 8 bits per pixel with a palette, or 24-bit as three 8-bit planes, and the PCX written here has 8-bit indexed or 24-bit RGB. Floating-point values are mapped to 8 bits per channel, and anything brighter than white clips.

Colour: scene-linear RGB, often ACEScg or linear Rec.709 in the EXR; PCX supports a 16 or 256-colour palette, or 24-bit RGB, written here as 8-bit sRGB.

Transparency: the EXR stores it as an A channel stored like any other channel; the PCX has none, so transparent areas are filled with the colour you choose.

Other images: the EXR can hold extra channels (depth, normals, render passes) and multiple parts; only the main image is converted.

Metadata: the EXR can carry named header attributes such as chromaticities, timecode and camera data; PCX can carry only a 128-byte header with the resolution, but nothing is copied across.

OpenEXR is the high dynamic range format of film visual effects. It stores half or full floating-point channels in linear light, plus any extra render passes, and is the working format of compositing pipelines.

An EXR starts with the magic number 76 2F 31 01 and a version field, then a header of named, typed attributes (channels, compression, dataWindow, displayWindow) and a table of offsets to scanline or tile blocks.

EXR files usually come from 3D renderers and compositing in Nuke, Blender, Houdini, After Effects and DaVinci Resolve.

PCX is the image format of ZSoft's PC Paintbrush, the standard for DOS paint programs, scanners and games before GIF and BMP took over. It compresses with a simple run-length scheme.

A PCX file has a 128-byte header (the byte 0x0A, version, encoding, bits per pixel, image window, DPI, a 16-colour palette and the number of colour planes), then RLE-compressed scanlines; 256-colour files end with the byte 0x0C and a 768-byte palette.

PCX is the better choice for DOS-era software, retro games and old fax or scanner tools, while EXR suits visual effects, compositing and 3D render output.

PCX strengths: Read by most legacy and modern viewers; Simple, lossless run-length compression. Drawbacks to weigh: Poor compression for photographs; No transparency; Obsolete outside retro software.