A LoRA (Low-Rank Adapter) is a small (2–500MB) fine-tuning add-on layered on a foundation model like Flux (see Flux Turbo Lora (8-step workflow)) to target specific improvements — style, character consistency, or photorealism — without retraining the whole model.
The flux-realism LoRA (from Excel lab/XLabs) specifically adjusts skin, hair, and wrinkle rendering to push Flux output toward photorealism. It's hosted on fal.ai alongside flux-1-pro and flux-1-dev, at roughly $0.32/generation vs ~$0.05 for flux-pro.
Realism also depends on the guidance/CFG scale parameter: fal.ai's default of 3.5 (at 28 inference steps) produces shiny, plasticky skin; lowering it to ~2 removes that artifact and is the reported sweet spot for realistic-looking skin.
Tool support gates access: LoRAs can only be applied via LoRA-capable tooling (ComfyUI's node graph, or fal.ai's hosted inference). Tools without LoRA support (e.g. Glif) cannot reach this level of realism regardless of prompt quality.
Compositional cue: off-center, 'amateur snapshot' framing reads as more authentic than polished professional-photo composition — a too-perfect composition now paradoxically signals AI generation.
See also Flux Tools (Depth/Canny/Redux/Fill) Model Architecture & Placement and Model Sampling Flux Width/Height for related Flux pipeline configuration concepts.