◎ Radiance Pro Viewer (Legacy)

If you loaded a Radiance workflow from before a certain version and it contains a node called "Radiance Pro Viewer (Legacy)," you are not looking at a different, better viewer. You are looking at the same Radiance Viewer under its old name. In the pack source, both FXTD_RadianceProViewer and FXTD_RadianceViewer map to the identical RadianceViewer class - one line each in the node registration. The "(Legacy)" tag exists so old JSON workflows don't break when they reference the old class name; the README says exactly that: "Legacy workflows that reference the older Pro Viewer name are mapped to the current viewer."

So everything that's true of the current Radiance Viewer is true here: GPU waveform, RGB parade, vectorscope and histogram scopes, Power Windows masking (radial + box with feather and rotation), the Comparison Bridge wipe with an 8-still reference shelf, anamorphic lens streaks with Brown–Conrady k1/k2 distortion, a 7×7 bilateral denoise, false color, zebra, channel isolation (RGB/R/G/B/Alpha/Luma), and export to 16-bit PNG with an .rhdr HDR sidecar or .exr.

What you actually set

• image (IMAGE or VIDEO) - the one required input.
• bit_depth - 8-bit (Fast), 16-bit (Quality), 16-bit + HDR Data (adds a float16 sidecar for the HDR color picker), or 32-bit Float (full fp32 sidecar, matching Nuke/Flame/Resolve precision at twice the VRAM). Use 32-bit when you're tuning HDR highlights and it's still smooth; drop to 16-bit for everyday viewing.
• compare_image - the reference for the A/B wipe.
• zdepth - a depth map you can display by pressing Z.

One honest gotcha, grounded in the schema: despite the description's "IMAGE passthrough" line, this registered node has no image outputs - it's a terminal display node (is_output_node: true, empty output list). If you need the image downstream too, branch the wire before it hits the viewer rather than chaining off it.

Viewer shortcuts worth knowing

The viewer is keyboard-driven. F fits the frame, 1 is 1:1, C/R/G/B/L switch RGB and channel views, Shift+A shows alpha, W toggles the waveform, V the vectorscope, S cycles safe areas. Space plays/pauses, arrows step frames. The delivery path (in the viewer's controls) bakes grain, bloom, halation, diffusion and denoise into the exported image - the interactive navigation overlays do not end up in the file, which is by design.

Why "Legacy" and why it's fine

New workflows should drop the current Radiance Viewer - it's the same node with the right name and the same features. Keep this class only if you're opening old .rad files. If you're trying to edit a very old workflow, the README's advice is to rebuild it through the current Radiance Workspace rather than fight stale widget ordering.

Install

Part of Radiance - ComfyUI Manager → search Radiance, or:

cd ComfyUI/custom_nodes
git clone https://github.com/fxtdstudios/radiance.git
cd radiance
pip install -r requirements.txt

Restart. The pack's community thread frames it as the hidden-gem HDR/EXR toolchain for film work - the viewer is where you actually look at all that float data.