A custom ComfyUI node that provides a dropdown menu of preset resolutions for film and photography aspect ratios. These resolutions are optimized for models with a native resolution of 1024x1024, such as Z-Image Turbo, SDXL, Pony, and Flux.

Preview

Features

Preset Resolutions: Select from a curated list of common aspect ratios and resolutions, including 4:5 Instagram Portrait, 3:4 / 4:3 Classic Photography, film formats, and widescreen options.
Manual Numeric Override: Easily override width and/or height with custom numeric values directly on the node (custom_width, custom_height).
Easy to Use: Simply select a preset from the dropdown or dial in custom dimensions to output the corresponding width and height.
Customizable: The list of resolutions can be easily modified in the Python script.

Installation

Clone or download this repository into your ComfyUI/custom_nodes/ folder.
Restart ComfyUI.

Usage

Add the "AfterDark Film AR Selector" node to your workflow from the "HackAfterDark" category.
Select a preset from the dropdown menu, or specify custom_width and/or custom_height numeric values to manually override the preset.
The node will output the corresponding width and height, which you can then connect to other nodes in your workflow.

AfterDark Gemini Prompter

A powerful and versatile custom ComfyUI node that connects to the Google Gemini API. It can be used as a sophisticated prompt builder, an image generator, or a multi-modal analysis tool.

Preview

Features

Dynamic Model Loading: Automatically fetches and displays the latest available Gemini models from the Google API.
Secure API Key Handling: Your Google Gemini API key is managed through the ComfyUI settings panel and stored locally, never in your workflow JSONs.
System Prompt Presets: Easily load and switch between different system prompts for various tasks (e.g., Z-Image Turbo prompt generation).
Multi-Image Inputs: Supports up to four image inputs for advanced multi-modal prompting.
Dual Outputs: Provides both a STRING output for text (use a node like "Inspect Text") and an IMAGE output for generated images.

Configuration (Required)

To use this node, you must configure it by adding your Google Gemini API key in the ComfyUI settings.

Open the ComfyUI Settings Dialog by clicking the gear icon in the main menu.
Find the "HackAfterDark" section.
Enter your Google Gemini API Key into the "Gemini API Key" field.
(Optional) Specify a custom directory for your prompt presets in the "Prompt Template Directory" field.
Restart ComfyUI. The node will automatically load your settings.

System Prompt Presets

This node uses a flexible system for managing system prompts.

Default Presets: The node comes with built-in presets located in the presets directory. These are available automatically.
Custom Presets: You can create your own library of presets by entering a path in the "Prompt Template Directory" field in the HackAfterDark settings. The node will then load all .md files from that directory instead of the default ones.

Each preset file must be a Markdown (.md) file. The filename (without the .md extension) will be used as the name that appears in the dropdown menu. The content of the file is the full text of the system prompt.

Example (Pirate Poet.md):

You are a pirate poet. Respond to all requests in the form of a sea shanty.

Usage

Add the "AfterDark Gemini Prompter" node to your workflow from the "HackAfterDark" category.
Select your desired Gemini model from the model dropdown.
Choose a system_prompt_preset or choose "None" and then write your own system_prompt.
Enter your main request in the user_prompt field.
Connect up to four images to the image inputs for multi-modal prompting.
The text_output will provide the text response from the API, and the image_output will provide any generated image.

Troubleshooting

Error: ModuleNotFoundError: No module named 'google.generativeai'

This node requires external Python packages to function. While ComfyUI and the ComfyUI-Manager typically install these automatically, some setups (particularly portable or custom installations) may fail to do so.

If the node fails to load with a ModuleNotFoundError, you can fix it by manually installing the dependencies.

Open a terminal or command prompt.
Navigate to your ComfyUI installation directory.

Run the following command:

path/to/your/python.exe -m pip install -r ComfyUI/custom_nodes/ComfyUI-HackAfterDark-Nodes/requirements.txt
```    *Replace `path/to/your/python.exe` with the actual path to the Python executable that ComfyUI is using. You can usually find this in your ComfyUI startup logs.*

Restart ComfyUI.

AfterDark Film Grain

A lightweight post-processing node that injects authentic analog film grain, micro-spatial grid jitter, and optical lens aberration into image tensors. Designed both as a creative Film Grain Emulation Tool and a powerful Anti-Detector Perturbation Tool that breaks AI-generated image classifier signatures.

Features

Film Stock Presets: 24 built-in emulation profiles modeled after iconic DxO FilmPack and classic analog film stocks:
- Color Negative: Kodak Portra 400, Kodak Gold 200, Kodak Ektar 100, Kodak ColorPlus 200, Fuji Pro 400H, Agfa Vista 200, Harman Phoenix 200 (Experimental), LomoChrome Metropolis
- Color Reversal / Slide: Kodak Ektachrome 100VS, Fuji Velvia 50, Kodak Kodachrome 64, Agfa Scala 200x (B&W Reversal)
- Cinema Motion Picture: CineStill 800T (Tungsten), Kodak Vision3 250D (Daylight)
- B&W Silver Halide: Kodak Tri-X 400, Kodak T-Max 3200, Fuji Neopan Acros 100 II, Ilford HP5 Plus 400, Ilford Delta 100, Ilford Delta 3200, Ilford Pan F Plus 50, Lomography Lady Grey 400 (120 Medium Format), Lomography Earl Grey 100
- Instant Analog: Polaroid 600 Emulsion
Physical Noise Distributions: gaussian (standard), poisson (shot noise), multiplicative (dye cloud), and laplacian (heavy-tailed halide spikes).
Luminance Exposure Response: Choice of exposure modulation profiles:
- Film (Midtone & Shadow): Silver halide density curve with heavy grain in shadows/midtones and soft highlight roll-off.
- Digital (Shadow Heavy): Low Signal-to-Noise Ratio (SNR) digital thermal dark current noise.
- Uniform (Flat): Equal noise distribution across all brightness levels.
Anti-Detector Protections: Sub-pixel micro_jitter, spatial_resample, non-linear gamma_shift, and edge_softening to disrupt Vision Transformer (ViT) patch token classifiers.

Exposure Response & Luminance Physics

In real physical photography, film grain is never a uniform noise layer pasted evenly across an image.

In physical film stock, grain is the visual result of metallic silver halide crystal clumping and organic C-41 dye cloud formation. Because chemical development reacts differently depending on light exposure, film grain looks completely different depending on the brightness or darkness of the scene:

Specular Highlights: Bright highlights saturate into dense metallic silver on negative film, dampening grain variance.
Midtones & Shadows: Midtones and dark shadows exhibit the highest grain density and visual structure.

Without factoring in local pixel luminance, noise applied equally across bright skies, skin tones, and deep shadows immediately looks artificial—like a flat digital overlay rather than authentic analog film emulsion.

Choosing the Right Exposure Response Mode

Mode	Real-World Physics	When to Use
`Film (Midtone & Shadow)` (Default)	Analog Silver Halide Emulsion: Grain density peaks in dark shadows and midtones (`L = 0.1 \to 0.6`) and rolls off smoothly in bright highlights (`L > 0.85`).	Best for Authentic Film Look: Use this for film stock emulations (Portra, Ektachrome, Tri-X). Keeps bright skies and specular highlights clean while giving shadows and skin midtones rich, organic film texture.
`Digital (Shadow Heavy)`	Digital Sensor Thermal Noise: Low Signal-to-Noise Ratio (SNR) in dark current causes sensor read noise to dominate dark shadow regions.	Best for Digital High-ISO Look: Use when emulating low-light photography shot on digital camera sensors (e.g. DSLR/mirrorless at ISO 6400). Concentrates noise in deep darks (`L < 0.30`).
`Uniform (Flat)`	Mathematical Uniform Overlay: Noise is applied with equal intensity across all pixels, regardless of brightness.	Best for Anti-Detector Perturbations: Use when your primary goal is disrupting Vision Transformer (ViT) patch classifiers across every spatial token, or for creative graphic texturing.

AfterDark Film LUT

A high-performance 3D LUT (Look-Up Table) color grading node. Reads .cube LUT files directly from ComfyUI's central models/luts/ directory.

Features

Central Model Directory Integration: Loads .cube files directly from ComfyUI/models/luts/ via ComfyUI's standard folder_paths manager. Your LUT files are preserved safely across node updates.
Built-In Dropdown Search: Standard ComfyUI combo dropdown select with built-in search filter support for quickly finding files across nested subdirectories.
GPU Hardware Acceleration: Uses PyTorch torch.nn.functional.grid_sample for 3D trilinear interpolation on GPU, applying complex LUTs in under 2 milliseconds.
Strength / Alpha Blending: Smooth slider control (0.0 \to 1.0) to blend between the original image and the color-graded LUT result.
Tone & Lighting Controls: Includes contrast (0.5 \to 1.5) for fine-tuning midtone contrast and black_lift (0.0 \to 0.10) to simulate authentic physical film shadow density (film toe).
Color Space Transfers: Supports "sRGB (Standard)", "Linear -> sRGB", and "sRGB -> Linear" gamma transfers to accommodate log/linear film print LUTs.

Credits

Author: HackAfterDark (https://hackafterdark.com)

Follow me on Civitai! https://civitai.com/user/HackAfterDark