Sandwich

Double-exposure blending for photographers. Two images, one composition. Metal-accelerated blend modes, transform controls, and XMP provenance that travels with your files.

See Features
Screenshot placeholder Main workspace showing base image with overlay blend, transform handles, blend mode selector, and opacity controls. Suggest capturing at 1200x750px with retina resolution.
Darkroom Technique

Classic blend modes

Screen
Multiply
Overlay
Soft Light
Hard Light
Difference
Exclusion
Luminosity
Metal-Accelerated

Blend with precision

Metal-Accelerated

Real-time blending at any resolution via CIFilter pipeline on the GPU.

Transform Controls

Drag to position, pinch to scale, rotate to rotate. Trackpad-native gestures.

Luminosity Masking

Threshold and feather controls to blend by brightness for precise composites.

Opacity Per Layer

Independent base and overlay opacity for fine-tuned compositing.

Presets

Save and recall blend recipes. Apply favorite looks to new image pairs.

Undo/Redo

Per-pairing undo stacks. Experiment freely with different blend approaches.

XMP Provenance

Every export records base, overlay, blend mode, and transforms in sw: namespace.

Fast Workflow

Every action accessible from the keyboard. Blend, adjust, and export without touching a menu.

Privacy-First

No accounts, no cloud, no tracking. Works entirely offline.

Suite Integration

Connected via XMP

Sandwich works with Photo Developer and Photo Archive Lite through XMP sidecars. Every blend is recorded, every provenance chain preserved.

  • Photo Developer exports serve as base and overlay images
  • Open results in PD for color grading — PD preserves sw: metadata
  • Photo Archive Lite detects Sandwich-processed files automatically
  • "Sandwich" appears in PAP's Processed By filter
  • Provenance keywords injected on Digg Photos upload
Prefix URI Key Fields
sw: http://ns.sandwich.app/1.0/ Version, BaseFilename, OverlayFilename, BlendMode, Opacity, LuminosityThreshold, Transform
Screenshot placeholder Diagram showing workflow: PD export → Sandwich blend → PD grade → PAP catalog. XMP sidecar shown with sw: namespace fields.
"In photography there is a reality so subtle that it becomes more real than reality."

— Alfred Stieglitz

Sandwich

A focused double-exposure tool built on Metal and CIFilter. Core blending, transform, presets, and XMP provenance complete.

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