Image preprocessing

Preprocessing executes once on the master source image prior to rendering target formats. This ensures adjustments such as color grading, auto-cropping, and watermarks remain uniform across the entire brand asset collection.

The sequence of processing operations:

1. Background removal
2. Background color / gradient fill
3. Edge smoothing
4. Noise reduction
5. Auto-crop
6. Color adjustments: grayscale, B&W, invert, hue, temperature, saturation, brightness, contrast
7. Sharpen or blur
8. Vignette
9. Drop shadow
10. Watermark

Color adjustments

Control	Form field	Default	Description
Grayscale	grayscale	false	Converts RGB channels to luminance while preserving alpha transparency
Black & white	bw	false	High-contrast binarization to pure black and pure white
Invert	invert	false	Inverts RGB values while retaining alpha values
Hue shift	hue_shift	0	Rotates color hue in degrees (-180° to +180°)
Temperature	temperature	0	Warm (positive, red-shifted) to cool (negative, blue-shifted), -100 to +100
Saturation	saturation	1.0	0.0 is fully desaturated, 1.0 is neutral, >1.0 enhances vibrance
Brightness	brightness	1.0	Multiplier scale matching saturation
Enhance contrast	enhance_contrast	false	Applies automated histogram contrast equalization

Grayscale vs B&W

grayscale preserves smooth midtone tonal gradients and is recommended for monochrome brand variations. bw applies binary thresholding, best suited for testing stencil legibility.

Sharpness and filtering

Control	Form field	Default	Notes
Sharpen	sharpen	false	Applies unsharp masking
Sharpen radius	sharpen_radius	1.0	Controls filter radius (higher values produce broader halos)
Blur	apply_blur	false	Applies Gaussian blur
Blur radius	blur_radius	2	Radius in pixels at source resolution
Noise reduction	noise_reduction	false	Median filter; utilizes OpenCV when present
Noise strength	noise_strength	1	Kernel size: higher values increase smoothing
Enhance quality	enhance_quality	false	Combined contrast, sharpening, and color correction pass

Sharpening and blurring are counteracting operations. Enabling both applies them sequentially, introducing blurring with halo artifacts. Select the single filter appropriate for your source.

Composition & framing

Control	Form field	Default	Notes
Auto-crop	auto_crop	false	Trims empty or uniform borders down to active subject bounds
Crop padding	crop_padding	10	Margin in pixels retained around the subject after boundary trimming
Vignette	vignette	false	Applies radial perimeter darkening
Vignette strength	vignette_strength	0.5	Intensity scale: 0.0 to 1.0

Auto-crop is particularly effective for logos exported with wide transparent margins. Combining auto-crop with 10-20 px padding ensures the mark fills all output canvases proportionally.

Drop shadow

Control	Form field	Default
Enable	shadow_effect	false
Opacity	shadow_opacity	0.3
Blur radius	shadow_blur	4
Offset X	shadow_offset_x	5
Offset Y	shadow_offset_y	5

Drop shadows are calculated from the alpha boundary. This requires an image with an active alpha channel, originating either from a transparent PNG/WebP source or via background removal.

Watermark overlay

Control	Form field	Default
Enable	add_watermark	false
Text	watermark_text	© BrandKit
Opacity	watermark_opacity	0.3

Watermarks render using Pillow bitmap rendering unless custom system TrueType fonts are mounted. Configure default text in config.json.

Output encoding options

These settings operate during per-canvas encoding rather than global preprocessing:

Control	Form field	Default	Notes
Quality	quality	95	Applies to JPEG and WebP; ignored by PNG and ICO
Strip metadata	strip_metadata	false	Discards ICC color profiles and leftover metadata from output files

Source EXIF handling

Uploaded master images are re-encoded through Pillow upon ingestion, which strips camera and GPS EXIF metadata. The strip_metadata parameter controls downstream target asset headers. Consult Privacy.

Customizing defaults

Default parameter values are declared under preprocessing_options in config.json. Modifying this structure alters the initial UI state.