Nuke Write

ComfyUI's Save Image writes a PNG and calls it a day. NukeWrite is the node you switch to when a PNG isn't the deliverable: it writes EXR, TIFF, DPX, HDR, TGA, BMP, even webp, with real bit-depth and compression control, and it can write image sequences with frame padding. It's the natural end of a Nuke-style pipeline - Read in, grade, write back out in a format the rest of your post chain actually wants.

You reach for it whenever the output has to survive contact with another tool. A render for a compositor needs 16-bit or 32-bit EXR, not 8-bit PNG. A contact sheet needs DPX. A sequence for video work needs %04d padding so the next app sees frames, not one file. NukeWrite does all of that, and its all_channels mode goes further - it can write an entire multi-pass EXR from a NUKE_PASSES bundle, the thing the pack's NukeReadMultiPass produces.

How it works

Writes go through OpenImageIO when available, falling back to OpenCV/PIL. Relative paths land in ComfyUI's output directory, subdirectories get created automatically, absolute paths are used as-is. file_path supports %04d and #### patterns; frame_padding (default 4) sets how many digits frames get. When there's no pattern at all, auto_sequence (default on) appends an incrementing number so test1.png, test2.png... never overwrite - turn it off and it clobbers the same file every run.

The channels dropdown is the interesting part. rgba and rgb write the IMAGE input normally. all_channels switches the node to multi-pass mode: it takes the passes input (the NUKE_PASSES bundle from NukeReadMultiPass) and writes every pass as a multi-channel EXR - and it's smart about it, applying the colorspace conversion only to light passes while leaving data passes (normals, depth, position, motion, IDs, mattes, UVs) untouched.

Like NukeRead, colorspace describes the file on disk and encodes to it from linear Rec.709: sRGB for PNG/JPG, linear for EXR, ACEScg if the post pipeline expects AP1. raw writes as-is.

Inputs that matter

• file_path + frame_start - where and when the sequence starts.
• file_type - exr, tiff, png, jpg, dpx, hdr, tga, bmp, webp. Default exr.
• bit_depth - 8, 16, 16f (half float), 32f. Default 16f - the sane default for EXR.
• compression - EXR codecs; dwaa default, zip/zips good for interchange.
• channels / passes - for multi-pass EXR output.

Outputs: the image (echoed) and a file_paths STRING telling you exactly what got written.

Installing it

Ships in Nuke Nodes. Manager: search "Nuke Nodes", install. Or:

cd ComfyUI/custom_nodes
git clone https://github.com/sumitchatterjee13/nuke-nodes-comfyui.git nuke-nodes
cd nuke-nodes
pip install -r requirements.txt

Restart, find it under Add Node → Nuke → IO. No models. OpenImageIO (from requirements) is what gives you the full format list.

Gotchas

• EXR wants a float bit depth. Writing 8-bit "EXR" is technically possible and practically useless. Stick with 16f/32f.
• PNG output washed out? Your pipeline is linear and you wrote with colorspace="raw". Set it to sRGB so the OETF gets applied and the file looks right in a viewer.
• all_channels needs the passes input wired. If you select it without a NUKE_PASSES connection, there's nothing to write - keep channels on rgba for plain image writes.
• Zero community footprint on this pack, so no threads to rescue you. The tooltips in the node are genuinely good - trust them, and the io_nodes.py source when they run out.