Preview Latent (Flux)

If you've ever dropped the plain PreviewLatent node onto a Flux workflow and watched it spit out a muddy, weirdly-colored thumbnail, this is the fix. The basic node hardcodes the SD1.5 latent format, and Flux doesn't live in SD1.5's latent space - its VAE uses 16 channels instead of 4, which means a wrong scale factor and a preview that looks nothing like the eventual render.

PreviewLatentFlux is the pack's Flux-specific version of that node. It's a thin wrapper over PreviewLatentAdvanced with the base_model locked to Flux, so you don't have to remember the scale-factor gotcha. Everything else is the same story: it peeks at your latent using a cheap decoder instead of the full VAE, shows you a full-resolution preview, and forwards the latent untouched so you can drop it mid-graph as a fancy reroute.

Inputs and output

One input:

• latent (LATENT) - your Flux latent, usually straight from a KSampler (Flux) output.

One output, latent (LATENT), which is the same latent you put in. It's an output node, so right-click the preview and "Save Image" keeps the workflow metadata in the PNG.

A note on preview quality: with no Flux-compatible TAESD decoder in ComfyUI/models/vae_approx/, the node falls back to latent2rgb, and the preview will look rough and desaturated. That's expected - it's a composition check, not a render. The KSampler previews you may be used to are capped at 512x512; this one is full resolution, which matters more the bigger your generation is.

Installing

Install the pack once and you get all five nodes. ComfyUI Manager (search "comfyui-previewlatent"), or:

cd ComfyUI/custom_nodes
git clone https://github.com/martijnat/comfyui-previewlatent

Restart ComfyUI. No Python dependencies, no requirements.txt. If the node won't load, update ComfyUI - the pack imports its latent_formats module at startup, and Flux/Wan/LTXV classes are newer additions.