Technical documentation

1. Introduction

imPRESS Studio is a professional PDF imposition tool for print shops, DTP studios and designers preparing publications for offset, digital and Print-on-Demand production.

Imposition is the process of arranging document pages on press sheets in the order and orientation needed so that, after printing, folding and trimming, a finished publication with correct pagination results. imPRESS Studio automates this: it takes PDF files, lays them out on press sheets (SRA3, A3, B2, Letter or any custom size) according to the chosen binding method, generates printer marks, compensates for creep, and exports a production-ready file — optionally as PDF/X-4.

1.1. Who it is for

• Offset and digital print shops — preparing forms, signatures, saddle-stitch and perfect-bound jobs.
• DTP studios and designers — quickly checking how a publication tiles onto a sheet and preparing print-ready files.
• Label and sticker production — step-and-repeat, roll-fed, Summa OPOS contour-cut markers.
• Print-on-Demand operators — automation via hot folders and the command-line interface.

1.2. Key capabilities

2. System architecture

imPRESS Studio uses a layered architecture with a clear separation between domain logic, PDF processing, export, automation and presentation. All projects compile into a single executable (imPRESS Studio.exe) — the app project includes the other modules' source files via <Compile Include>, which simplifies distribution and avoids DLL locking.

2.1. Modules (projects)

2.2. Technology stack

2.3. Dependency composition & the STA thread

CompositionRoot.Build() builds a single IServiceProvider shared by the GUI and CLI paths. Long-lived services (engine, analyzer, composer, validators, ICC profile manager, hot folder subsystem) are registered as singletons; view-models as transient (each window gets a fresh instance). The exception is TemplateEditorViewModel — a singleton, so in-progress template edits survive across dialog opens.

All binding strategies are registered as IBindingStrategy and injected into ImpositionEngine as a dictionary keyed by binding type. All preflight validators are registered as IPrepressValidator — registration order defines report order.

2.4. Data flow (from file to press)

1. Load & analyze — PdfAnalyzer reads page count, dimensions, boxes, fonts, images, transparency.
2. Plan — ImpositionEngine.Plan() picks the strategy from Template.Binding and populates ImpositionJob.SheetLayouts (sheets with page positions — PagePlacement).
3. Preview — PdfPreviewRenderer (PDFium) rasterizes sheets; ImpositionCanvas draws them with LOD heuristics (detail level driven by zoom).
4. Preflight — PrepressValidationEngine runs all validators and produces a PrepressValidationReport.
5. Compose — PdfComposer (PdfSharpCore) places pages on sheets, draws marks and overlay.
6. Convert (optional) — ExportPipeline invokes Ghostscript with a PDF/X definition file and ICC profile.
7. Save — the finished PDF at the output location.

3. Installation & requirements

3.1. System requirements

3.2. Installation

The application ships as an installer (Inno Setup) generated by the build/pack.ps1 script. After installation, launch it from the Start menu or directly via imPRESS Studio.exe.

Dynamic files (configuration, templates, licenses, logs, the hot folder database) are never written into the Program Files directory — they go to %APPDATA% (roaming data) and %LOCALAPPDATA% (logs, SQLite, cache). See chapter 17. Files & data locations.

3.3. First run

1. Launch the app — on first start the data directories are created and the default configuration is loaded.
2. If no active license is found, the activation window appears (see chapter 4).
3. Built-in templates and marks profiles are seeded on first run.

4. Licensing & activation

imPRESS Studio uses a machine-bound license. The machine identifier is a hash computed from the computer's hardware parameters (MachineFingerprint, using the System.Management module).

4.1. Activation process

1. Open the License window (in the header) or wait for the activation window at startup.
2. Copy the machine identifier (fingerprint) — a unique hash of your computer.
3. Send it to your vendor when ordering a license.
4. You will receive an activation key (a Base64 string) or a license file (.json).
5. Paste the key and click Activate license — or load the license file.

4.2. License editions

4.3. License gate in the CLI

CLI export is subject to the same license gate as the GUI. If the license is invalid, the impose command returns exit code 2 and prints an activation instruction.

5. User interface

The main window is divided into three columns plus a header and a status bar.

5.1. Quick start — five steps

1. Pick or create a template — the Template button in the header or Manage templates in the left panel.
2. Load a PDF — + Add files… (Ctrl+O) or drag a file onto the window. Selecting several files and clicking Load selected merges them into one document.
3. Plan the imposition — Ctrl+P or Plan.
4. Check the preview — navigate with ← →, zoom with the wheel, toggle marks, show front/back or spread.
5. Export — Ctrl+E, choose the range, PDF standard and optionally PDF/X-4.

6. Imposition templates — full reference

A template (Template) is a complete imposition work plan stored as JSON. Below is the full field reference of the model.

6.1. Top-level fields

6.2. Margins (LayoutMargins)

6.3. Template validation

Template.Validate() enforces correctness rules before planning:

• Sheet and trim dimensions must be positive; N-up X/Y positive; margins non-negative.
• For saddle and perfect binding: pages per signature positive and a multiple of 4.
• 8-page signature (saddle): page count a multiple of 8.
• Stacked copies mode: at least 2 copies per sheet.
• Mode-specific sheet-fit check (e.g. saddle verifies required width/height = 2×trim + gutter + 2×margin).

6.4. Managing templates

• Pick a ready-made template from the library.
• Create a new template from scratch (the New button).
• Edit parameters and save under your own name (a JSON file).
• Import/export templates as .json files — to share between workstations.

7. Binding types & layout strategies

Each binding type has a dedicated strategy (IBindingStrategy) chosen by ImpositionEngine based on the template's binding field.

7.1. Saddle stitch (SaddleStitch)

Folded signatures stapled at the spine. Typically 8 or 16 pages per signature. Ideal for thin publications (up to ~60 pages). Requires creep compensation at higher page counts. Layout modes (SaddleSheetLayout):

7.2. Perfect bound (PerfectBound)

Each signature is a separate section glued at the spine. Used for thicker books (over ~50 pages). Requires a spine margin (spineMm) whose width depends on the total book thickness.

7.3. Wire / spiral (Wiro)

Wire or spiral binding — single pages with punched holes.

7.4. N-up ganging (Ganging)

Multiple different flyers/pages on one sheet, no binding. The strategy cycles through successive source pages and never rotates copies.

7.5. Folding: Z-fold, Gatefold, Accordion

The sheet is folded without cutting (leaflets, brochures, maps). Panel count is in FoldOptions.PanelCount:

All of this geometry is computed in one place — FoldGeometry — shared by the layout strategy, template validation, the preview and the marks renderer, so all four agree on where the sheet gets creased:

Size interpretation mode (FoldOptions.SizeMode) 1.5.11

A folded product can be described either way round; the choice is stored in the template:

Templates written before 1.5.11 deserialize as Panel — exactly what their trim already meant — so their sheets are unchanged.

Panel fit check 1.5.11

Up to 1.5.10 only gatefold had a fit check; Z-fold and accordion fell through to the generic N-up test, which — with the NUpX = 1 every fold preset ships — asked whether one panel fits. Three panels of 210 mm on a 297 mm sheet passed validation, and the strategy then produced panels overlapping by 114 mm. All three folding bindings now share one check:

requiredWidth  = panels × panelWidth + (panels − 1) × gutter + 2 × sheetMargin
requiredHeight = panelHeight + 2 × sheetMargin

The message names what it measured: "3 panels of 210.0mm" or "unfolded product 297×210mm = 3×99.0mm".

Fold marks 1.5.11

Up to 1.5.10 fold marks were drawn for saddle stitch only, even though every fold preset ships with them enabled. Since 1.5.11 dashed ticks are drawn at the top and bottom sheet edge at the positions returned by FoldLayout.FoldLinesPt() — identically in the preview and in the exported PDF.

7.6. Roll-fed step-and-repeat (RollFed) 1.2

Sticker/label production on a continuous roll (web-press). Sheet width = physical roll width. Options (RollOptions):

7.7. Sheet-fed step & repeat (StepAndRepeat) 1.2

Replicates ONE source page into an NxM grid with optional rotation patterns and pitch (centre-to-centre) spacing. Differs from Ganging in that Ganging cycles through multiple pages and never rotates copies.

8. Margins, bleed & printer marks

8.1. Print concepts

Bleed

Artwork extending past the trim lines — typically 3 mm. Prevents white edges after a slightly inaccurate cut.

Safe zone

Minimum distance of text from the trim line — typically 5 mm.

Gutter

Gap between adjacent pages on the sheet.

Sheet margin

Distance from the sheet edge to the first page — required by the press gripper.

Spine

Spine width for perfect bound (paper thickness × page count).

8.2. Printer marks (MarksOptions)

8.3. Marks profiles 1.3

Newer templates use marks profiles referenced via marksProfileRef instead of flat toggles. Profiles are stored in a file-backed store and seeded with built-ins on first run. The resolver uses the profile when the reference is non-empty, otherwise it falls back to the legacy marks toggles. Profiles are edited in a dedicated editor (MarksProfileEditor) and support, among others: registration mark style and position, colour-bar style, mark ink colours, barcodes, and the K grayscale wedge (1.4.4).

8.4. Overprint simulation

The preview can simulate overprint using multiply blend — it shows the darkening when CMYK inks overprint, helping you anticipate the press result.

9. Creep compensation

In saddle stitch all signatures nest inside each other. The inner pages "push out" past the outer edge by the thickness of the preceding sheets. After trimming the outer edge, the inner pages' margins become narrower — by several millimetres on thicker publications.

Creep compensation shifts the inner pages' content toward the spine so that, after trimming, the margins are identical on all pages.

9.1. Options (CreepOptions)

9.2. How to enable

1. Open the template manager, the Creep tab.
2. Tick Enable compensation and enter the paper thickness.
3. Turn on the Creep option in the preview — orange dashed lines show the compensation per signature.

10. Source PDF files

The Source PDF files tab in the left panel manages the list of input documents.

• + Add files… (Ctrl+O) — a dialog to select multiple PDFs at once.
• Drag and drop — drop PDF files onto the window (Win32 drag&drop, hence the STA requirement).
• Checkboxes — select files to load; more than one + Load selected merges them into one document in list order.
• Arrows ▲▼ — reorder before merging.
• Info — details of the selected PDF: page count, dimensions, trim, metadata, fonts, transparency, encryption, tagging, OCG (layers).
• ✕ — remove the selected file; Remove unchecked — clear files without a checkbox.

11. Sheet preview

11.1. Navigation

• Mouse wheel — zoom relative to the cursor.
• Drag — pan the view.
• ← / → — previous / next sheet.
• Thumbnails — jump to a sheet; the "Sheet X / Y" field is the counter.
• Ctrl+0 or F — fit to window; R — rotate 90°; Ctrl++/Ctrl+- — zoom.
• Quick-zoom buttons: 50%, Fit, 200%.

11.2. What you can visualize

• Back / Front (⇄) — toggle sheet sides (double-sided printing).
• Spread — front and back side by side, to check registration.
• Marks — crop, registration, colour bars, fold.
• Creep — orange compensation lines per signature.
• Overprint — multiply-blend simulation.
• View rotation (↻) — 90° to check orientation on press.

12. Preflight — prepress validation

Preflight is an automated check of PDF correctness before printing. The deep analyzer (PdfPreflightAnalyzer) inspects the file, and the validation engine (PrepressValidationEngine) runs a set of validators producing a report (PrepressValidationReport) with severity levels.

12.1. The check set

Validators are plug-ins (IPrepressValidator) registered in the container; registration order is the order categories appear in the report. Every finding carries a stable, language-independent code (e.g. BLEED_LOW) that filtering acts on and that the “what to fix first” advice is keyed by.

12.2. Press profiles and per-check severity 1.5.8 / 1.5.12

Thresholds describe the machine rather than the job, so they live in a press profile (PreflightProfileLibrary): ink limit, contone and line-art resolution floors, safe zone, trapping expectation, spot-colour limit. Five built-in profiles (coated and uncoated offset, newsprint, digital, large format) plus whatever the operator saves.

Each check additionally carries a severity policy keyed by code — Off, Info, Warning, Error — enforced centrally in PrepressValidationContext.Add, so every validator inherits it without knowing the mechanism exists. A shop trapping in the RIP silences the trapping advisory; one running CMYK-only raises RGB to an error. Off means gone, not demoted: the finding is neither listed nor counted, so it cannot gate a strict export from behind a filter.

12.3. File repairs 1.5.7 / 1.6.0

A repair (IPrepressFixup) works on a copy — the operator’s original is never touched — and the written file is re-validated afterwards to show which codes actually disappeared and which survived. The repairs card in the file-info dialog appears only when a repair genuinely applies to that report.

12.4. The report, strict mode and saving

The report groups findings by category, severest-first within each, and opens with a “what to fix first” panel (PreflightSummaryGenerator) carrying advice keyed to the specific code. Longer reports gain a severity filter; the advice panel is always computed from the whole report rather than the filtered subset.

Saving the report (PreflightReportWriter, File info → Validation → Save report) renders the result as plain text: a header with the file, profile and verdict, then findings severest-first, repeats of one code collapsed, and consecutive pages folded into ranges (1-3, 7, 11-13). A prepress finding is an argument with a customer about whose file is wrong, and it has to travel with evidence.

Strict mode stops an export on warnings; errors stop it regardless of mode. Informational findings gate nothing — entries such as signature padding or an odd page count in a duplex job describe entirely normal production.

13. Export & PDF/X packaging

The three flavours differ in exactly three ways, handled in one place (ImpressExportEngine.PackageAsPdfX):

How X-1a and X-3 handle transparency 1.5.12

Both are defined on PDF 1.4, which has no transparency. The engine does not flatten: turning genuinely non-opaque artwork into opaque marks means compositing the page, which is a rasteriser's job and would silently convert vector text into pixels. Instead NativeTransparencyFlattener separates two cases:

Inert entries are stripped only when the whole document is free of transparency that paints: an isolated or knockout group becomes observable once real transparency is in play.

Why the removal happens on the finished file 1.5.12

PdfSharpCore stamps /Group << /CS /DeviceRGB /S /Transparency >> onto every page it serialises — measured on a blank page with no content and no transparency. Removing the key through the object model achieves nothing, because the writer puts it back. The groups are therefore taken out of the written file, and the replacement is byte-for-byte the same length (spaces are legal whitespace between PDF tokens), which keeps the cross-reference table valid without a rebuild.

After saving, the file is re-read and verified: surviving transparency (and, for X-1a, surviving DeviceRGB) fails the export. A library change surfaces as a refused export rather than as a file claiming conformance it does not have.

13.1. The export process

After pressing Export (Ctrl+E), ExportPipeline.RunAsync performs:

1. Source analysis — pages, fonts, images, transparency.
2. Preflight — correctness check (optionally strict).
3. Composition — placing pages on sheets + marks + overlay.
4. Optional PDF/X-4 — natively via the imPRESS Export Engine (with vector-RGB conversion through ICC) or via Ghostscript.
5. Save — the finished PDF at the output location.

13.2. Export options (ExportOptions)

13.3. PDF/X-4 — requirements and profiles

PDF/X-4 (ISO 15930-7) is the print standard supporting transparency, layers and ICC profiles, recommended by most print shops. Since 1.5.2 the packaging is done by default by the native imPRESS Export Engine (OutputIntent + XMP + TrimBox + PDF 1.6, vector RGB→CMYK conversion through the ICC profile using the Windows colour engine); files with RGB images and the X-1a/X-3 modes are handled by Ghostscript (bundled, version 10.07) with a definition file (PdfXDefinitionFile / PDFX_def.ps) and an ICC profile.

14. Job statistics

After planning the imposition, the right panel shows statistics computed by JobStatistics:

15. Hot Folder — automation 1.1.0

The hot folder subsystem monitors designated directories and automatically processes files dropped into them. The architecture is based on Microsoft.Extensions.Hosting and is fault-tolerant (retry/backoff via Polly, idempotency via a SQLite ledger).

15.1. Components

15.2. Management

Hot folders are configured in the manager dialog (HotFolderManagerDialog) and the editor (HotFolderEditDialog), or from the CLI (see chapter 16). The default concurrent Ghostscript limit is 2 (configurable in global settings).

15.3. Choosing a template 1.6.0

A folder points at a template three ways: from the list of saved templates (the same ones the template manager shows), from the built-in starting points, or by path to a .json file. A chosen preset is written into the templates directory and the folder points at the resulting file — from that moment it is a template like any other, editable in the manager. An existing file of the same name is left alone, so a preset the operator has tuned survives being picked again.

15.4. JDF / XJDF job tickets 1.6.0

With Accept job tickets enabled, the folder also watches .jdf and .xjdf files. A ticket is not the work — it describes the work and names the file that is. The reader (JobTicketReader) handles both generations: JDF 1.x, where intent values sit in span sub-elements carrying Actual and Preferred (negotiated winning over requested) or are written straight onto the intent element, and XJDF 2.x’s flattened form.

Read from the ticket: the artwork reference (FileSpec/@URL), finished size, press sheet, page count, sidedness, binding and run length. Every CIP4 dimension is in points of 1/72 inch and is converted to millimetres in the reader; numbers are parsed invariantly.

15.5. Windows service mode 1.6.0

Hot folders can run as a service (HotFolderWindowsService), so they work with nobody logged in and come back after a reboot. The service key is ImpressStudioHotFolders and the display name imPRESS Studio Hot Folders. Registration and control: hotfolder service install / start / stop / uninstall / status, or the Windows service row in the hot folder manager, which elevates through UAC.

• Data directory. Configuration, the licence and templates live in the profile of whoever set the folders up, and the service does not run as that person — as LocalSystem its %APPDATA% is under C:\Windows\System32\config. The installer writes the path into the service command as --data-dir, parsed before the application is composed so the whole process resolves one set of roots.
• Account. LocalSystem by default; for hot folders on a network share, give it a domain account — LocalSystem authenticates as the machine and a file server usually refuses it.
• Restart on failure configured at install time: three attempts a minute apart, reset daily.
• SCM handshake. The start is acknowledged immediately and performed on a background thread (starting the host is I/O, possibly on a slow share); a start that fails stops the service with a non-zero exit code rather than sitting in “running” while watching nothing.

16. Command-line interface (CLI)

imPRESS Studio recognizes command-line arguments (System.CommandLine parser). With no arguments it launches the GUI; with a verb argument it runs headless.

16.1. The impose command

"imPRESS Studio.exe" impose \
    --source input.pdf \
    --output output.pdf \
    --template template.json \
    --pdfx4

Exit codes: 0 — success; 1 — error; 2 — missing/invalid license.

16.2. The license command

"imPRESS Studio.exe" license fingerprint
"imPRESS Studio.exe" license info
"imPRESS Studio.exe" license activate --key BASE64_KEY

16.3. The hotfolder command

"imPRESS Studio.exe" hotfolder run      # foreground daemon (Ctrl+C stops)
"imPRESS Studio.exe" hotfolder list     # status of all folders
"imPRESS Studio.exe" hotfolder start <GUID>
"imPRESS Studio.exe" hotfolder stop  <GUID>
"imPRESS Studio.exe" hotfolder reload   # reload hotfolders.json

The hotfolder run command must be the process's first command — it is intercepted in Program.Main before the parser, because it requires the host to be wired up around the CLI.

17. Files & data locations

The AppPaths helper centralizes all paths. Roaming data goes to %APPDATA%\imPRESS Studio, local data to %LOCALAPPDATA%\imPRESS Studio.

18. Localization & units

The interface is fully localized through LocalizationService and the LocExtension markup extension. Built-in languages include Polish (pl), English (en), German (de), Spanish (es), French (fr), Italian (it), Japanese (ja), Korean (ko), Russian (ru) and Turkish (tr). Custom language packs (.json) can be added in the localization overrides directory.

Display units (DisplayUnitsService) support millimetres and inches. The data model is canonical in millimetres; conversion happens at the XAML boundary via MmConverter. When toggling mm/inch, template presets swap ISO ↔ US sets (1.4.5).

19. Keyboard shortcuts

20. Troubleshooting

"No active license"

Open License and paste the activation key or load the .json file.

PDF/X-4 export doesn't work

Ghostscript is bundled, but for a custom path point to gswin64c.exe in the options (or --gs in the CLI). Remember the ICC profile read permission under SAFER mode.

Preview shows black pages

Check whether the PDF is encrypted (Info in the left panel). Restricted PDFs may require removing protection.

Pages run "off" the sheet

Trim + bleed + gutter + sheet margins exceed the sheet size. Pick a larger sheet or reduce margins/bleed. Template validation reports the required width/height.

"The file is in use by another process"

Close the output file in Acrobat/a browser, or choose a different path.

Slow export of large files

Multi-sheet PDF/X-4 export is intensive. Consider exporting without PDF/X-4 and converting in bulk via a script, or use hot folders with throttling.

21. Glossary

Imposition

Arranging pages on press sheets so that, after printing, folding and trimming, a publication with correct pagination results.

Signature

A group of pages printed on one sheet (typically 4, 8 or 16).

N-Up

Number of pages on one side of a sheet (e.g. 2×2 = 4 pages).

Trim

Final page size after trimming the bleed.

Bleed

Artwork extending past the trim lines.

Creep

Inner pages pushing out past the outer edge in saddle stitch.

PDF/X-4

The ISO 15930-7 print standard (transparency, layers, ICC).

Preflight

Automated correctness check of a file before printing.

Registration marks

Crosshair marks for aligning CMYK separations.

Pitch

Centre-to-centre distance between copies (step & repeat).

Nesting

Optimal nesting of shapes (rotations) for less waste.

OPOS

Summa plotter contour-marker system (print&cut).

OCG (Optional Content Groups)

PDF layers that can be toggled on/off.

Hot folder

A monitored directory — files dropped in are processed automatically.

LOD (Level of Detail)

Rendering detail level driven by zoom.

22. Version history (milestones)

The complete, detailed changelog is in the changelog.html file bundled with the application.