ProEXR

OpenEXR is a versatile file format for visual effects, especially conducive to smooth 32-bit HDR image workflows. To fully harness those capabilities, ProEXR is a plug-in that was designed to allow users to access OpenEXR functions from their Adobe Photoshop, Premiere, and After Effects programs.

For instance, Photoshop has trouble reading and exporting layered EXR files, which ProEXR helps with. Essentially, storage of layers under one file is now made possible through this plug-in, which can also save those layers as individual files.

As we're discussing layers, it's also worth pointing out that ProEXR will additionally read image buffers created by your 3D renderer, and then create individual Photoshop layers for each.

The various compression options of OpenEXR are fully available here: though EXR mostly entails lossless compression, lossy compression can be achieved in numerous ways. B44 compression, as well as Luminance/Chroma sampling can drastically reduce the size of HDR images, while maintaining their general quality, without adding in any visible artifacts.

Retention of EXR color spaces is present, and so is the support for 32-bit, as well as 16-bit floating points. Users can also make use of their full control over alpha channel processing, all through this free, open-source plug-in.