Which pigments and materials differ?

The system combines spatial and spectral evidence to map pigments, possible overpaints, previous interventions and degradation patterns without taking physical samples. CIELAB coordinates and reflectance spectra sampled in at least 13 bands remain tied to their exact position on the object.

Where are overpaints or previous interventions?

Registered image bands are captured under controlled illumination with spectral and radiometric references. Spectra at selected points are compared and areas with similar or contrasting reflectance behaviour are grouped into material-difference maps that preserve the exact location of each measurement.

How is the surface changing over time?

DeltaPick and DeltaViewer align calibrated acquisitions from different sessions and calculate colorimetric and spectral differences pixel by pixel, producing condition and difference layers for comparison over time.

Does the analysis require sampling from the object?

No. Hypercolorimetric multispectral imaging (HMI) is non-invasive. Calibrated acquisition and processing deliver approximately 98% accuracy and repeatability without removing samples from the object.

Colour documentation of a fresco: a colour reference target on a tripod in front of a painted Roman emperor, with a camera and studio light.

Cultural Heritage & Conservation

Map pigments, distinguish original materials from later overpaints and retouchings, and monitor degradation over time, all without physical sampling.

Spectral data

Reflectance spectrum of point 01 from 350 to 950 nanometres: reflectance stays near 0.05 up to 550 nm, rises to about 0.3 by 700 nm and levels off near 0.3 to 0.34 through the near infrared. — Reflectance spectrum350–950 nm

Pigment match table for point 01: 1 Terra di Siena bruciata, Delta E 3.05, spectral likelihood 98%; 2 Ocra rossa, 3.66, 96%; 3 Ocra gialla plus Nero, 12.74, 94%; 4 Siena naturale, 12.27, 93%; 5 Terra di Siena bruciata plus Bianco, 4.51, 91%; 6 Bolo, 6.38, 90%; 7 Giallo Indiano, 9.67, 90%; 8 Red bukhara, 8.64, 92%. — Pigment matchBest · Terra di Siena bruciata

Reflectance spectrum of point 02 from 350 to 950 nanometres: reflectance rises from about 0.07 at 350 nm to about 0.6 by 600 nm and stays between 0.55 and 0.65 into the near infrared. — Reflectance spectrum350–950 nm

Pigment match table for point 02: 1 Ocra gialla plus Bianco, Delta E 1.64, spectral likelihood 96%; 2 Giallo Marte plus Bianco, 3.61, 91%; 3 Orpimento, 6.13, 89%; 4 Bolo plus Bianco, 14.72, 88%; 5 Siena naturale plus Bianco, 7.77, 84%; 6 Ocra gialla, 9.30, 84%; 7 Giallo Indiano plus Bianco, 11.00, 84%. — Pigment matchBest · Ocra gialla + Bianco

Reflectance spectrum of point 03 from 350 to 950 nanometres: reflectance rises gradually from about 0.05 at 350 nm to about 0.55 by 750 nm and stays near 0.55 into the near infrared. — Reflectance spectrum350–950 nm

Pigment match table for point 03: 1 Ocra rossa plus Bianco, Delta E 5.63, spectral likelihood 96%; 2 Ocra gialla, 7.88, 93%; 3 Siena naturale plus Bianco, 8.09, 93%; 4 Giallo Indiano plus Bianco, 5.04, 92%; 5 Bolo plus Bianco, 7.99, 92%; 6 Cinabro monte Amiata (Kremer), 18.19, 91%; 7 Bolo, 10.38, 90%. — Pigment matchBest · Ocra rossa + Bianco

Before you intervene

Answers that guide treatment decisions

Non-invasive answers, each tied to an exact point on the object and backed by measured data.

Pigment differentiation
Tell apart materials that look identical to the eye by comparing their full spectral signatures.
Beneath the surface
Reveal underdrawings, pentimenti and hidden details concealed beneath the visible paint layer.
Pigment identification & mapping
Match each point to reference pigment libraries and map where every pigment appears.
Condition monitoring
Repeat calibrated captures over time to measure fading, darkening or new damage.

Same Colour, Different Pigment

Two blues on Giotto's polyptych match by colour, yet the spectrum shows they are different pigments, measured without touching the work.

Giotto's polyptych: five gilded panels with the Virgin and Child at the centre and a predella of five medallions below — Bologna Polyptych (Polittico di Giotto),
Pinacoteca Nazionale di Bologna, Italy

Zoom on the predella: the medallion of Christ on a blue ground between two blue and gold foliate panels. A small green square marks the selected reference point on the blue ground. — Region of interest
Reference point

Colorimetric likelihood map: the blue ground of the medallion and the side panels appear as solid, continuous white. — Colorimetric likelihood
Looks identical

Spectral likelihood map of the same area and point: the match is broken up and parts of the blue disappear. — Spectral likelihood
Different pigment revealed

Spectral difference reveals what the eye cannot see.

From the object to the decision

Capture the spectrum
Calibrated UV to near-infrared images (300–1000 nm) in 13, 18 or 24 bands, taken on site without contact. Every point is a real measurement, 98%+ precise.
Powered by SpectraPick →
Document true colour
Colour-accurate images (ΔE2000 ≤ 2) from any camera, even a smartphone, in standard formats. Ideal for condition reports, catalogues and archives.
Powered by VisiPick →
Measure true scale
Perspective is corrected and every image gets a millimetre scale, so walls, vaults and large paintings can be measured and mapped accurately.
Powered by PickPerspective →
Analyse and reveal
Read any point's spectrum, identify pigments against reference libraries, and reveal underdrawings and hidden damage with PCA and IR/UV false colour.
Powered by PickViewer →
Monitor over time
Compare captures from different campaigns, pixel by pixel, to measure fading, darkening or new damage before it is visible to the eye.
Powered by DeltaPick →

What lies beneath the surface

Hidden details, Revealed

Under the mother's mantle, Principal component analysis (PCA) reveals a face that cannot be seen on the painted surface.

01
CaptureCalibrated multispectral images, from ultraviolet to near-infrared, taken on site.
02
AnalysePCA separates the information carried by each spectral band.
03
RevealA face emerges under the mantle, invisible in normal light.

Non-invasiveNo samplingMeasured on-site

ROI

Guido Reni, Massacre of the Innocents
Pinacoteca Nazionale di Bologna

Selected area as PCA image, showing a hidden face

VISIBLEPCA Compare visible and PCA

RESEARCH & PROFESSIONAL NETWORK

Connected to European research and the conservation supply chain.

Profilocolore is an SME beneficiary of the UNVEIL Marie Skłodowska-Curie Actions Doctoral Network and an Assorestauro associate member in analysis, survey and diagnostics.

Pigment Identification & Mapping

A single point on the red balustrade is matched to cinnabar in our spectral pigment database. The same pigment is then mapped across the entire page.

Persian manuscript page, c. 1400: garden scene with figures and a red balustrade

Persian manuscript, c. 1400 · Musée du Louvre, Paris

Selected area

Close-up of the red balustrade with the measured point

CinnabarΔE 1.71

Cadmium redΔE 5.47

Cadmium red + whiteΔE 5.94

Identified:Cinnabar

Mapping cinnabar across the whole artwork

Black and white pigment map: in white, every area painted with cinnabar

Our pigment map:Cinnabar in white

Measurement confidence

Scientific measurements, not only diagnostic images.

Calibrated acquisition and processing deliver more than 98% accuracy and repeatability, turning each image into comparable colorimetric and spectral evidence.

Pixel by pixel

Measured evidence

CIELAB coordinates and reflectance spectra sampled in at least 13 bands remain tied to their exact position on the object.

Traceable

Controlled references

Absolute radiometric and colorimetric references connect field acquisition to laboratory measurement and international metrology standards.

In site

Non-invasive operation

Portable, battery-capable configurations support acquisition on site without contact with the surface.

START A CONVERSATION

Cultural Heritage & Conservation

Pigment differentiation

Beneath the surface

Pigment identification & mapping

Condition monitoring

Bologna Polyptych (Polittico di Giotto),

Region of interest

Colorimetric likelihood

Spectral likelihood

From the object to the decision

Capture the spectrum

Document true colour

Measure true scale

Analyse and reveal

Monitor over time