In the digital world, the concept of DPI (dots per inch) is often reduced to a simple number. In reality, it encompasses multi-layered knowledge of conservation, archival science, and color management. In art digitization, resolution determines whether every detail is captured. – from micro cracks in the paint to the texture of the canvas.
What is DPI really?
DPI, or dots per inch, is a parameter that describes how detailed a scanner captures an image. It's worth noting that in the context of scanning, the more correct term is PPI (pixels per inch), because it's about pixels, not print dots. Equally important is the distinction between optical resolution (actual hardware capabilities) and interpolated (artificially added pixels that do not provide new information).
When digitizing works of art, bit depth is also important – the number of bits per pixel. Standard 24-bit provides 16.7 million colors, but archives are increasingly using 48-bit recording, which provides much better tonal gradations and more faithful color reproduction.
What DPI range is used for scanning works of art?
High resolution is not just about a larger file – it is, above all, a wealth of information and security for the facilityIn practice, this means the ability to recreate a work of art in nearly identical quality to the original, without the need to re-examine the precious artifact. Scanning at 400-600 DPI allows for:
- Capture the details such as micro-cracks, brush marks, substrate texture or paper structure, which are crucial for conservation research and technological analyses.
- Ensure high-quality reproduction – thanks to this resolution, images can be printed in large formats (e.g. posters, exhibition catalogues) without losing sharpness and color reproduction
- Secure the facility for the future – in line with the “once and for all” principle, avoiding the need for re-scanning and minimizing the exposure of the work to light and manipulation.
As a result, 400-600 DPI has become the gold standard for museums and archives, combining documentation, conservation and publishing needs.
Recommended DPI values
| Application | Minimum resolution | Justification |
| Online-only publication | 150 DPI | Sufficient for ≤4K monitors |
| Printed in 1:1 scale | 300 DPI | Printing standard ISO 12647 |
| Magnifications 2×-3× | 600 DPI | Scaling without losing quality |
| Conservation research and archive | 600-1,000 DPI | Detail analysis <0.1 mm |
How many “bits” does art need?
The standard 24-bit format works well for preview copies, but for archives and fine art reproductions, 48-bit format (16 bits per RGB channel) is used. This recording minimizes banding, improves tonal transitions, and enables safe color correction, which is especially important when editing and analyzing works with subtle color transitions or faded pigments.
Color and lighting
Color calibration is an essential element of the process, encompassing not only the use of ColorChecker-type swatches, but also precise white balance adjustment, regular profiling of output devices (monitors, cameras, scanners) and control of lighting parameters.
LED light sources with a temperature of 5,500 K and a high CRI are used to ensure neutral lighting conditions, minimize metamerism, and avoid color shifts. Combined with hardware monitor calibration and the use of ICC profiles, this allows for reproductions that faithfully reproduce the original colors and enable consistent workflows throughout the entire digitization process, from scanning to prepress.
Files and their archiving
- TIFF 6.0 uncompressed – master file for archives.
- JPEG 2000 (lossless) – access to research resources with smaller file sizes.
- JPEG – preview and web versions.
Principle 3-2-1 (3 copies, 2 different media, 1 off-site) is the foundation of secure archiving.
The most common mistakes in digitization
The most common mistakes result from insufficient understanding of the specifics of the process and its impact on the quality of the final material:
- Focus on interpolated resolution instead of optical – interpolation does not add real details, but only artificially enlarges the file.
- Bit depth too low (8-bit) in the case of works with subtle tonal transitions – it leads to banding and loss of important color information.
- No color or lamp calibration – results in color distortions, which are particularly visible when reproducing works with color nuances.
- Saving in JPEG only – lossy format causes image degradation during subsequent editing and is not suitable for sample files.
- Skipping control tests and templates – lack of comparison with the original results in unconscious reproduction errors.
Avoiding these errors is key to obtaining digital copies that truly serve as faithful and lasting reproductions of the originals.