MRC PDF Kompressor 4.0
Professional document compression with Mixed Raster Content technology – up to 95% size reduction, BSI TR-Resiscan compliant.
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Description & documentation
Professional document compression (demo version)
The MRCCompressor is a powerful tool for converting scanned images (TIF, JPG, PNG) into extremely compact, audit-proof PDF files.
By using the Mixed Raster Content (MRC) method, the software separates text from image backgrounds. The result is documents that are up to 95% smaller than the original, while keeping the text crisp and perfectly legible.
This version uses a newly developed hybrid engine that requires no expensive commercial licences and delivers results comparable to the market leaders.
What's new in version 4.0
- Colour text layers: coloured headings, stamps and logos stay sharp and true to colour (up to 4 automatically detected colour layers at 300 DPI).
- JBIG2 compression of the text mask (pattern-safe, no character substitution); optional symbol mode for maximum compression (
--jbig2symbols). - Smart Inpainting now fills text areas with the real paper colour instead of white – no more light halos on coloured or grey paper.
- Multi-page TIFF files are supported (each page becomes its own PDF page).
- Considerably faster: parallel page processing and optimised filters (batch processing about 40–50 % faster, correspondingly more on multi-core CPUs).
- PDF/A-1b output is now fully standard-compliant.
- Small dark elements (bullet points, ticked checkboxes, punch holes) are reliably preserved.
- Preview without freezing (background computation) and new switches in the interface for colour text layers, Smart Inpainting, edge silhouette and JBIG2 symbol mode.
- Download size halved (31 instead of 62 MB); new licence model (PolyForm Small Business License 1.0.0).
The highlights (features)
- Extremely high compression: reduces file sizes from, e.g., 5 MB to under 100 KB (in text mode). In internal comparison tests more compact than leading commercial MRC solutions – at the same legibility.
- BSI TR-Resiscan compliant: pattern-safe method without JBIG2 symbol matching. No characters are replaced or altered – ideal for replacement scanning.
- NEW – colour text layers: coloured headings, stamps, logos and markings are automatically detected and preserved as separate, crisp 300-DPI layers in their original colour, instead of blurring into the compressed background.
- Smart Inpainting: reconstructs the background behind the text with the real paper colour – no artefacts, better compression.
- Background Bleaching: removes grey haze and noise for pure-white backgrounds.
- PDF/A-1b support: creates long-term archivable files to ISO standard.
- Multipage TIFF: multi-page TIFF files are automatically converted into multi-page PDFs.
- Split-view interface with real-time preview (original vs. result), synchronised zoom and layer view – the preview computes in the background without blocking operation.
- Batch & CLI: fully automatable via the command line, now with parallel page processing for high throughput.
How it works
The tool splits the scanned image into several layers (Mixed Raster Content):
- Text mask: the black text is extracted at high resolution (300 DPI) and compressed space-efficiently as JBIG2 – using a pattern-safe method without character substitution (CCITT G4 as fallback).
- Colour text layers (new): coloured text, stamps and logos are grouped by colour and embedded as separate, crisp layers in their original colour.
- Background layer: paper structure and images are processed separately, smoothed and efficiently compressed as JPEG2000 or JPEG.
In the final PDF these layers are overlaid exactly – the result is a fraction of the original size with full legibility.
Instructions & operation
1. Graphical interface (GUI)
Start MrcCompressor.exe for interactive mode:
- Load one or several images.
- Use the sliders on the left to find the perfect balance between quality and size.
- Or: choose between "Text Optimised" (for invoices/letters) and "Graphic Optimised" (for certificates/photos).
- Copy the command generated at the bottom left for your scripts.
- Save the generated PDF file.
2. Command line (CLI)
Ideal for servers or batch scripts.
Syntax: MrcCompressor.exe "Input.tif" "Output.pdf" [options]
Example:
MrcCompressor.exe "Scan01.tif" "ArchivScan01.pdf" --mode text --pdfa
Important parameters:
- --mode [auto|text|image]: selects the algorithm (automatic, text bleaching or image preservation).
- --pdfa: creates a PDF/A-1b file (requires srgb.icc in the folder).
- --threshold [0-255]: sensitivity of text detection (default: 150).
- --noblobs: automatically removes large black borders from the text mask.
When called via the command line (CMD/PowerShell), the following parameters are available:
Parameter overview for MRC Compressor
This overview describes all available settings of the MRC Compressor. They can be controlled both via the user interface (GUI) and via the command line (CLI).
The settings are stored in the file mrc_profiles.xml.
Main settings
| Setting | CLI parameter | Explanation | Default |
|---|---|---|---|
| Mode | --mode [auto/text/image] | Controls the processing strategy. Auto: automatically detects whether a page is text or graphic. Text: optimised for sharp text, removes background details. Image: preserves colours and photos, but needs more storage space. | Auto |
| Auto-Detect Threshold | --autothresh [0-100] | Sensitivity threshold for auto mode. Specifies what percentage of the page must be "colourful" for it to be recognised as graphic/image. Low (e.g. 2%): even small coloured logos switch to graphic mode. High (e.g. 15%): only real photos switch over; documents with colour accents stay in text mode. | 8% |
| PDF/A | --pdfa | Creates a PDF/A-1b compliant file (for long-term archiving). Disables transparencies. | Off |
MRC segmentation (mask & text)
| Setting | CLI parameter | Explanation |
|---|---|---|
| Text Threshold | --threshold [0-255] | "Where does text end, where does background begin?" Determines how dark a pixel must be to be recognised as text. 0 = pure black only, 255 = everything. A higher value also detects lighter/grey text, but risks recognising dirt as text. |
| Colour Sensitivity | --sens [0-100] | Determines how sensitively the mask ignores colour differences. A high value merges similar colours, which makes the mask cleaner ("less blotchy"). |
| Remove blobs | --noblobs | When active, large black areas (e.g. black borders from scanning) are automatically removed and assigned to the background. |
| Max. text size | --blobsize [px] | Maximum size (in pixels) an object may have to still count as "text". Anything larger is treated as graphic/background. |
Background optimisation
| Setting | CLI parameter | Explanation |
|---|---|---|
| Background scaling | --scale [1-10] | Strongest factor for the file size. The background is stored downscaled. 1 = original: best quality, large file. 3 = standard: background has 1/3 resolution (at 300 dpi that corresponds to 100 dpi). Usually completely sufficient for text documents, since the sharp text lies on top. |
| Background quality | --quality [0-100] | Compression quality of the background layer (JPEG2000 or JPEG). Low (<30): saves space, but creates "block" artefacts. High (>70): hardly any artefacts, larger file. |
| Graphic preservation | --bgsens [0-200] | Determines how much detail should be kept in the background. A low value "washes out" the background more (good for text scans), a high value preserves structures (good for patterned backgrounds). |
| Blur | --blur [0-5] | Applies a blur over the background. Helps to remove noise and halftone dots in the paper. |
| Saturation | --sat [0.0-5.0] | Adjusts the colour saturation of the background. 0.0: black and white (greyscale). 1.0: original. >1.0: boosts colours (good for pale scans). |
| Background bleaching | --white [0-255] | "White point": all brightness values above this are turned to pure white (transparent). Ideal for removing grey paper or show-through from the back ("paper cleaning"). |
Vectorisation
| Setting | CLI parameter | Explanation |
|---|---|---|
| Vectorise | --vectorize | Tries to convert the recognised text into real vector graphics instead of pixels. Advantage: infinitely sharp when zooming. Disadvantage: can deform letters on poor scans ("O" becomes "Q"). This makes the scan no longer pattern-safe / TR-Resiscan compliant! |
| Keep as vector | --keepvector | Stores the vectors directly in the PDF (larger file, best quality). If disabled, the vectors are rasterised (smaller file). |
| Bake into BG | --bakevector | Renders the vectors back into the background layer. Uses vectorisation only to "smooth" the edges. |
Filters & effects
| Setting | CLI parameter | Explanation |
|---|---|---|
| Sharpen | --sharpen [0-20] | Re-sharpens the background after downscaling to keep details legible. |
| Edge optimisation | --edge [0-30] | Artificially enhances edges (unsharp masking), e.g. to make signatures stand out more clearly on the background. |
| Colours (Posterize) | --posterize [2-128] | Reduces the number of colours in the background (e.g. to 16 colours). Creates a "comic look" and saves a huge amount of storage, since areas of the same colour compress better. |
| Watermark (only available in mrc_profiles.xml) | Writes a text in semi-transparent red over the finished PDF. |
New options in version 4.0
| Setting | CLI parameter | Explanation |
|---|---|---|
| JBIG2 symbol mode | --jbig2symbols | Enables JBIG2 symbol matching for maximum compression – up to 65% higher compression rate in text mode. Caution: not pattern-safe / not TR-Resiscan compliant – only use when audit-proof archiving is not required. |
| Colour text layers off | --nocolorfg | Disables the colour text layers; coloured text then ends up in the compressed background. |
| Inpainting off | --noinpaint | Disables Smart Inpainting; text areas are filled hard with white instead of the real paper colour. |
| Edge silhouette off | --nooutline | Disables the edge silhouette in the background – produces smaller files. |
Syntax
The call is made via the command line (CMD/PowerShell)
MrcCompressor.exe "Input file" "Output file" [parameters](If no output file is specified, the input file is saved with the extension .pdf in the same folder.)
Archiving (PDF/A):
MrcCompressor.exe "Scan.tif" "Archiv.pdf" --pdfaSystem requirements
- System: Windows 10/11 (64-bit), .NET Framework 4.8 or newer.
- Visual C++ Redistributable (x64)
System requirements
- Windows 10/11 (64-bit)
- Microsoft .NET Framework 4.8 or newer
- Visual C++ Redistributable (x64)
Licence & costs
Free for private individuals and small businesses – under the PolyForm Small Business License 1.0.0: free use, copying and distribution for private individuals, associations, educational institutions and organisations with fewer than 100 people and under USD 1 million in annual revenue.
Licensable only above this size: larger companies need a paid licence for business use (enquiries via kreutzweb.de). The full licence text is included as LICENSE.txt; notes on the included open-source components in THIRD-PARTY-NOTICES.txt.
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Free for private individuals and small businesses (PolyForm Small Business License). Provided "as is" without warranty.
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