A local Windows app that prepares a whole folder of photos for printing.
Open a folder → pick a preset → “Prepare”. Originals are never changed; the results land in a
PrintPrep_… subfolder next to them. Everything runs offline on your computer.
Requires Windows 10/11 x64.
All screenshots here use synthetic demo images, not real photos.
Light theme · Start screen · Before / after · Per-photo edits · Crop · Neural network at work · Neural result · 1:1 zoom · Preset manager · App settings · First-run tour · Splash
The interface speaks English and Russian and comes in dark, light or “as in Windows” themes.
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One workspace. Presets on the left, a live preview with a filmstrip in the middle, the preset card, histogram and settings on the right. Every change is visible immediately — there is no “Apply” button. Ctrl+Z / Ctrl+Y undo and redo.
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Presets are the main idea. One click applies a preset to every photo in the folder. The selected preset is outlined, and a banner says plainly that you are editing that preset and the change goes to all photos. Built-in groups collapse; your own presets live in “Mine”. Save, save as, rename, duplicate, export/import files, and a separate preset manager.
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Per-photo edits on top of the preset (“This photo” tab): crop, rotation, straighten, light, colour, neural network. Copy them to selected photos or move them into the preset. Edits are saved per folder automatically.
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Smart auto correction, measured rather than guessed (
tools/eval_auto.py):- white balance by voting of near-neutral surfaces in log-chroma space, textured surfaces weighted above smooth sky and backdrops; a real cast is corrected almost fully, while warm scene light (sunset, lamps) is kept because it leaves the shadows neutral; detected skin must stay natural;
- exposure from the log-average and the highlight headroom, with faces as a second opinion; dark low-key and bright high-key frames are left alone;
- auto levels at 0.1 % clipping only when both ends of the histogram are empty; shadows lifted only where they hold detail (a black backdrop stays black); strong veils go to a dark-channel dehaze.
Measured by adding known faults (colour casts, ±EV, flat contrast, haze) to good photos and averaging ΔE (CIELAB) to the original: on six real photographs from the Windows image set (landscapes, sunset, fog) it removes 43 % of the colour error and changes the good originals by only ΔE 1.89. On a stress set of 19 images (wallpapers, including 3D abstractions) the figures are 28 % and ΔE 3.15; on the 24 Kodak film scans, 34 % and ΔE 2.06. Results depend on the photos — see the research notes (in Russian).
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Manual grading like Lightroom (exposure, contrast, highlights, shadows, whites, blacks, temperature, tint, vibrance, saturation, clarity, dehaze, noise) and nine styles.
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One neural network — Real-ESRGAN. Restores detail and cleans JPEG artefacts when a photo has to be enlarged 1.3× or more (sources up to 4 MP). It runs once per photo in the background with progress and time left, and the result shows right in the preview. The best settings are automatic; an “Advanced” dialog offers strength and a clean ↔ detail control (Real-ESRGAN’s official denoise interpolation plus returned source texture), so the result no longer looks smeared.
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Printing. mm + PPI, exact pixels, long edge or original size; smart framing on faces, borders, safe zone; output sharpening for screen, gloss or matte; print-brightness compensation; printer ICC profiles with soft proof and gamut warning.
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Quality. float32 throughout, 16-bit TIFF/PNG in and out, exact Display P3 / Adobe RGB conversion, EXIF without GPS, dithering.
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Fast on weak PCs. Previews decode a reduced JPEG (DCT scaling) instead of the full file; the full resolution is read only for 1:1, the neural network and export. Neighbouring photos are prefetched, so switching after viewing takes ~0.03 s; a slider drag redraws in ~0.06 s. Export runs strips in parallel. The build is a folder (fast start, antivirus-friendly), ~75 MB zipped.
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Friendly. An animated splash while the heavy modules load, a short spotlight tour on first run (repeat it from App settings), toolbar that switches to icons in narrow windows.
Downloads. Get PrintPrep-Setup.exe (installer) or PrintPrep-Windows-x64.zip (portable) from the
latest release; SHA256SUMS.txt next to them
has the checksums. Builds of unreleased commits are attached to each successful “Windows build” run in
the Actions tab (downloading them requires signing in
to GitHub, and GitHub keeps them for a limited time). You can also build the app yourself with
build_exe.bat (below).
One file, one button. PrintPrep-Setup.exe (from the release, or built into dist/) →
“Install”. It installs per user (no admin rights) into %LOCALAPPDATA%\Programs\Print Prep, adds
desktop and Start menu shortcuts, registers in Settings → Apps (uninstall from there) and starts the
app. Updating is the same: run the new setup, presets are kept. The setup is not code-signed, so
SmartScreen may ask for “More info → Run anyway”. A portable dist/PrintPrep-Windows-x64.zip is built
as well.
Building: on Windows with Python 3.12 x64 run build_exe.bat. It runs the tests, builds the
app folder, checks its self-test, packs the ZIP, builds the installer (installer/) and verifies
it with a silent install → self-test → uninstall (tools/check_installer.py).
From source:
py -3.12 -m venv .venv
.venv\Scripts\python -m pip install -r requirements.txt
.venv\Scripts\python print_prep.pyTests (requirements-dev.txt adds pytest and PyInstaller; this is what build_exe.bat runs):
.venv\Scripts\python -m pip install -r requirements-dev.txt
set QT_QPA_PLATFORM=offscreen
.venv\Scripts\python -m pytest -qTools: tools/eval_auto.py <folder of good JPEGs> — objective check of auto correction;
tools/profile_workflow.py — speed of every step; tools/screenshot_demo.py — regenerate the
screenshots above; tools/make_icon.py — the logo.
More: user guide (EN) · инструкция (RU) · research and measurements (in Russian) · acceptance checklist (in Russian) · third-party components (in Russian) · bundled models.
Limits: no RAW/HEIC and no direct printing. The working space is sRGB (wide gamut is compressed gently). Output to a printer ICC profile is 8-bit only.
The logo is an original abstract composition after Kandinsky’s Several Circles: glowing discs that read as lenses and paint at once, seen through viewfinder corners.
See LICENSE. The licenses/ folder contains third-party license texts only; see THIRD_PARTY.md.