Color Matching Research Articles

Robust Distribution‐Aware Color Correction for Single‐Shot Images

AbstractColor correction for photographed images is an ill‐posed problem. It is also a crucial initial step towards material acquisition for inverse rendering methods or pipelines. Several state‐of‐the‐art methods rely on reducing color differences for imaged reference color chart blocks of known color values to devise or optimize their solution. In this paper, we first establish through simulations the limitation of this minimality criteria which in principle results in overfitting. Next, we study and propose a few spatial distribution measures to augment the evaluation criteria. Thereafter, we propose a novel patch‐based, white‐point centric approach that processes luminance and chrominance information separately to improve on the color matching task. We compare our method qualitatively with several state‐of‐the art methods using our augmented evaluation criteria along with quantitative examinations. Finally, we perform rigorous experiments and demonstrate results to clearly establish the benefits of our proposed method.

Development of imine-azo-dyes derived from vanillin and salicylaldehyde for pH-sensing in smart packaging

Purpose This study aims to describe the design and synthesis of two novel azo and imine chromophores-based dyes derived from two different aldehydes with intramolecular colour matching that are pH sensitive. Design/methodology/approach The visible absorption wavelength (λmax) was extended when azo chromophore was included in imine-based systems. The dyed patterns created sophisticated colour-changing paper packaging sensors with pH-sensitive chromophores using alum as a mediator or mordant. Due to the tight adhesive bonding, the dyes on paper’s cellulose fibres could not be removed by ordinary water even at extremely high or low pH, which was confirmed by scanning electron microscopy analysis. The dyed patterns demonstrated an evident, sensitive and fast colour-changing mechanism with varying pH, from pale yellow to red for Dye-I and from pale yellow to brown-violet for Dye-II. Findings The λmax for colour changing was recorded from 400 to 490 nm for Dye-I, whereas from 400 to 520 for Dye-II. The freshness judgement of food was checked using actual experiments with cooked crab spoilage, where the cooked crab was incubated at 37 oC for 6 h to see the noticeable colour change from yellow to brown-violet with Dye-II. The colour-changing mechanism was studied with Fourier transform infrared (FTIR) spectra at different pH, and thin layer chromatography, nuclear magnetic resonance and FTIR spectroscopy studied the desired structure formation of the dyes. Potential uses for smart packaging sensors include quickly detecting food freshness during transportation or right before consumption. Originality/value 1. Two novel azo-imine dyes have been synthesized with a pH-responsive effect. 2. The pH-responsive mechanism was studied. 3. The study was supported by computational chemistry using density functional theory. 4. The obtained dyes were used to make pH-responsive sensors for seafood packaging to judge the freshness.

Versatile Double Bandgap Photonic Crystals of High Color Saturation.

Double bandgap photonic crystals (PCs) exhibit significant potential for applications in various color display-related fields. However, they show low color saturation and inadequate color modulation capabilities. This study presents a viable approach to the fabrication of double bandgap photonic inks diffracting typical secondary colors and other composite colors by simply mixing two photonic nanochains (PNCs) of different primary colors as pigments in an appropriate percentage following the conventional RGB color matching method. In this approach, the PNCs are magnetically responsive and display three primary colors that can be synthesized by combining hydrogen bond-guided and magnetic field (H)-assisted template polymerization. The as-prepared double bandgap photonic inks present high color saturation due to the fixed and narrow full-width at half-maxima of the parent PNCs with a suitable chain length. Furthermore, they can be used to easily produce a flexible double bandgap PC film by embedding the PNCs into a gel, such as polyacrylamide, facilitating fast steady display performance without the requirement of an external magnetic field. This research not only presents the unique advantages of PNCs in constructing multi-bandgap PCs but also establishes the feasibility of utilizing PNCs in practical applications within the fields of anti-counterfeiting and flexible wearable devices.

Optical transparent metamaterial with multi-band compatible camouflage based on inverse design.

Infrared (IR) thermal camouflage and management are deeply desirable in the field of military and astronomy. While IR compatible with laser camouflage technology is extensively studied to counter modern detection systems, most existing strategies for visible light camouflage focus on color matching, which is not suitable for scenarios requiring transparency. In this work, we propose an optically transparent metamaterial with multi-band compatible camouflage capability based on the inverse design. The metamaterial consists of Ag grating, Si3N4 dielectric spacer layer, Ag reflection layer, and Si3N4 anti-reflective layer. An ideal multi-band compatible spectrum is involved in the inverse design algorithm. Calculated results demonstrate high transmittance (T0.38-0.78µm = 0.70) in the visible region, low reflectance (R1.55µm = 0.01) in laser working wavelength, high reflectance (R3-5µm = 0.86 and R8-14µm = 0.92) in the dual-band atmospheric window, and high emissivity (ɛ5-8µm = 0.61) for the non-atmospheric window. The radiative heat flux in the detected band is 31W/m2 and 201W/m2 respectively. Furthermore, the incident and polarized insensitivity of the proposed metamaterial supports applicability for practical situations. This work, emphasizes an effective strategy for conducting optically transparent design with compatible IR-laser camouflage as well as radiative cooling properties by an automated design approach.

Conservation Treatment of Metallic Painted Plastic Sculpture: Color Matching Profiling

In the conservation treatment of modern and contemporary art, the color matching process is sometimes carried out by reflecting the artist information. In particular, in the case of artworks in which the artist survives, originality and authenticity are secured by referring to the artist information and intended appearance in consideration of the rights of integrity when processing irreversible work such as repainting. ‘Flowers of tomorrow’ by artist Jeong Hwa Choi is a sculpture with paint on the surface, and some of the structures were eliminated and cracked to reveal the inner base layer, so conservation treatment was carried out. Through the artist interview, it was confirmed that the paint used in the artwork was metallic corrosion paint, and the color change and chromaticity were measured according to the application time of the rust activator to quantify the appropriate color matching method for the artwork. Based on the results, conservation treatment was carried out stably and the appearance of the artwork was restored. This process will be recorded as a manual and used for color matching in conservation treatment of related artworks in the future.

Retrospective Clinical Evaluation of RMGIC/GIC Class V Restorations.

The aim of this retrospective study was to evaluate the clinical performance of glass-ionomer cement (GIC) and resin-modified glass-ionomer cement (RMGIC) materials in Class V carious cervical lesions restored by dental students. Ninety-six (96) restorations performed with either GIC (Fuji IX) (n = 39) or RMGIC (Fuji II LC) (n = 57) were evaluated using the modified USPHS criteria by two independent investigators at two follow-up evaluations (two years apart). The Fisher statistical test was used to compare USPHS criteria and examine significant differences, with a significance level set at p < 0.05. The Kaplan-Meier algorithm was used to calculate the survival probability. The overall success rate of Class V restorations was 72.9% at the second follow-up evaluation, with restorations ranging in age from 2.5 to 3.5 years. The RMGIC (Fuji II LC) restorations exhibited a significantly higher overall success rate compared to the GIC (Fuji IX) restorations (p = 0.0104). Significant differences were observed in retention (p = 0.0034) and color match (p = 0.0023).

Comparison of morbidity at the donor site and clinical efficacy at the recipient site between two different connective tissue graft harvesting techniques from the palate: A randomized clinical trial.

This study was conducted to compare the pain levels in patients and the clinical efficacy of grafts obtained using two techniques, namely de-epithelialized gingival graft (DGG) and subepithelial connective tissue graft (SCTG), in combination with coronally advanced flap (CAF) for the treatment of multiple adjacent gingival recessions. Twelve patients were treated using DGG+CAF on one side and SCTG+CAF on the other. The patients' pain levels at the surgical site, the number of analgesics taken on days 3 and 7, the mean root coverage (MRC), the percentage of complete root coverage (CRC), color match, and gingival thickness (GT) at the graft recipient site were evaluated 6 months after surgery. The total number of analgesics taken during the 7-day period after surgery and pain levels at the surgical site from day 3 to day 7 were significantly higher in the DGG+CAF group compared to the SCTG+CAF group (P=0.001). In the 6-month follow-up, color match and CRC were significantly higher in the SCTG+CAF group, while GT was significantly higher in the DGG+CAF group. There was no significant difference in MRC between the two groups. The pain and analgesic consumption levels were higher in the DGG+CAF group compared to the SCTG+CAF group, and the recipient site had a weaker color match. However, this technique can lead to a greater increase in the thickness of the grafted area.

Esthetical Properties of Single-Shade and Multishade Composites in Posterior Teeth.

This study aimed to compare the aesthetic properties of posterior composite restorations made with a multishade (MS) or single-shade (SS) material. For that, 23 extracted human molars were used. The shade determination was performed, and the occlusal anatomy was registered by a custom-made stamp. Then, class I preparations were made, and each tooth was restored twice, using two different composites of MS/opacity layering material (Admira Fusion-Voco) and an SS/opacity bulk-fill composite (Admira Fusion X-tra-Voco). After finishing the first restoration with the MS material, a standardized picture was taken, and the restoration was removed. Then, the preparation was restored again with the other composite, obtaining a new picture. The pictures were randomly analyzed by 10 calibrated evaluators regarding color match using the FDI criteria. The evaluators were blinded to the restorative material used. Data were analyzed using an unpaired t-test and Wilcoxon test. The significance level adopted in the study was 5%. As a result, there were nonsignificant differences between the composites evaluated for color match, as well nonsignificant differences were obtained related to which restorative technique produced the best aesthetic results. Only for darker shades (A4, B4, and C4), most of the evaluators considered the restorations made with the MS material more aesthetic than with the SS, while for the other shades, nonsignificant differences were observed. Therefore, the choice of the SS and the MS/opacity composites does not influence the aesthetic outcome of posterior restorations for the lighter shades. However, the use of bulk fill material for dark shades is less favorable than the MS layering ones.

Reconstruction of Full-Thickness Helical Defects Using a Superior Auricular Artery-Based Postauricular Chondrocutaneous Flap.

The helix is the most common localization of auricular defects. Various techniques have been successfully used for the reconstruction of helical defects. However, redistributing the remaining auricular tissue to supply an ideal reconstruction base provides the best possible esthetic outcomes. The aim of this study is to present a new design for a postauricular chondrocutaneous flap to reconstruct the 3-dimensional curve and the folded structures in full-thickness helical defects. Nineteen patients with full-thickness helical defects were treated with the superior pedicle chondrocutaneous flap based on the superior auricular artery. The flap was designed on the postauricular area and comprised 3 sections, namely, deepithelialized, chondrocutaneous, and cutaneous sections (proximal to distal). Levels of patient's satisfaction on the final shape and auricular symmetry, and tissue compatibility between the flap and surrounding tissues were evaluated by the patients and objective observers. The overall dimensions, projections, and curved structures of the defective helix maintained a smooth and contiguous appearance without asymmetry, notching, or trap-door deformities. The color, texture, and thickness of the flaps matched well with the adjacent auricles, and there was a moderate positive correlation between patient (9.47 ± 0.51) and observer (8.68 ± 0.63) correlation scores (r = 0.7485). The vast majority of the patients were very satisfied with the surgical outcome, and there was a statistically significant improvement in patient satisfaction (mean preoperative score, 1.26 ± 0.45; mean 12-month score, 4.79 ± 0.42; P < 0.00001). Reconstruction of full-thickness helical defects requires "like tissue" characteristics and 3-dimensional cartilage support to avoid depression and notch deformities. The postauricular chondrocutaneous flap based on the superior auricular artery was shown to preserve the helical curve and folded sulcus, retain the size and subunits of the auricle, and ensure a color, texture, and thickness match between the flap and the adjacent tissues.

Reconstruction of Upper Third Defect of the Auricle by Conchal Cartilage Graft and Coverage by Postauricular Flap.

The defects of the upper third of the auricle are considered significant reconstructive challenges, as they require frequent operations with a high risk of morbidity at the donor site and result in unacceptable cosmetic abnormalities. Is to perform the reconstruction of a full-thickness auricular defect located in the upper third of the ear using a conchal cartilage graft with postauricular flap coverage, aiming to minimize both donor and recipient morbidity. The current study included 20 patients with unilateral upper-third auricular defects. The repair involved 2 components: a cartilage graft from the concha to provide structural support and a flap for coverage. Follow-up was conducted for 6 months after the operation. Successful outcomes were achieved in both subjective and doctors' assessments. Regarding subjective outcomes, 85% of the patients reported high satisfaction (P < .001). In terms of doctors' subjective assessment, 90% of the patients had excellent results (P < .001). Mild early and postoperative complications, if encountered, resolved spontaneously. The use of a combined conchal cartilage graft and postauricular flap in treating a full-thickness upper third auricular defect is safe and effective, with no major complications. The technique preserves the cosmetic and functional outcomes of the auricle, providing an excellent color match and minimal donor-site morbidity.

A Color Matching Method for Mosaic HY-1 Satellite Images in Antarctica

Antarctic mapping with satellite images is an important basic task for polar environmental monitoring. Since the first Chinese marine satellite was launched in 2002, China has formed three series of more than 10 marine satellites in orbit. As global operational monitoring satellites of ocean color series, HY-1C and HY-1D have good coverage characteristics and imaging performance in polar regions, and they provide an effective tool for Antarctic monitoring and mapping. In this paper, Antarctic images acquired by the HY-1 satellite Coastal Zone Imager (CZI) sensor were used to study color matching in the mosaic process. According to the CZI characteristics for Antarctic imaging, experiments were carried out on the illuminance nonuniformity of a single image and color registration of multiple images. A gray-level segmentation color-matching method is proposed to solve the problem of image overstretching in the Antarctic image color-matching process. The results and statistical analysis show that the proposed method can effectively eliminate the color deviation between HY-1 Antarctic images, and the mosaic results have a good effect.

Visual and Instrumental Color Match Evaluation of Single Shade Composites before and after Bleaching Procedures: A Pilot Study

Background: One of the major challenges in restorative dentistry is to obtain an adequate color match between composite restorations and the surrounding tooth. This match depends on several chromatic variables related to the composite itself but also to the teeth. Bleaching procedures are not to be able to modify the shade of composite restorations to a lighter color as it does on natural teeth. Objective: The objective of this study is to evaluate the visual and instrumental color match of two single-shade resin-based composites in human-extracted teeth before and after bleaching treatment. Methods: Six extracted human posterior sound teeth were used. Round-shaped V-class cavities (2x2x4mm) were prepared buccally 2mm away from the CEJ. Two single-shade resin composites (OM-Omnichroma and VE-Venus Diamond One) were used for the restorations. Tooth color was measured using an intraoral spectrophotometer. Visual analysis was carried out by 16 calibrated observers, and the differences were graded from 0 (excellent match) to 4 (huge mismatch). Teeth were then bleached using 40% H 2O2 (Opalescence Boost PF, Ultradent), and visual and instrumental evaluations were performed after 24 hours. Results: Before bleaching, visual analysis showed a mean value of 0.16 for OM and 0.24 for VE. After bleaching, the color match showed a mean value of 0.14 for OM and 0.22 for VE. Regarding the instrumental analysis, each restoration matched the tooth VITA scale grade before bleaching and followed the natural tooth VITA scale grade after bleaching procedures. Conclusion: Within the limits of this pilot study, both composites seem to have excellent color-match properties with the surrounding tooth structure.

A 32-month evaluation of lithium disilicate cantilever resin-bonded fixed dental prostheses to replace a missing maxillary incisor

The absence of a tooth in the esthetic zone can cause emotional and social distress. The use of minimally invasive and visually pleasing lithium disilicate resin-bonded fixed dental prostheses (RBFDPs) may be a suitable option for replacing a missing maxillary incisor. However, the available literature on lithium disilicate cantilever RBFDPs is limited. This retrospective multicenter study assessed the survival and success rates of lithium disilicate anterior cantilever RBFDPs with an average follow-up period of 3 years up to 9 years. RBFDPs delivered by 3 operators were clinically assessed for survival using a modified United States Public Health Service criteria list. The incidence density was determined for each criterion and operator. The standard error and 95% confidence interval were calculated for each incidence density difference (α=.05 for all analyses). A total of 108 RBFDPs were evaluated after a mean period of 32.45 months, ranging from 14 days to 111 months. None of the restorations exhibited failure, carious lesions, or fractures during the follow-up period. The primary reasons for reduced success rates were inflammation of the surrounding soft tissues and discoloration, with incidence densities of 0.074 and 0.057 per year, respectively. Significant differences were observed among RBFDPs from different operators for criteria that included adaptation, color match, marginal adaptation, polishability, surface staining, gingival health, and antagonist wear. Cantilever lithium disilicate RBFDPs appear to be suitable for short-term restoration. RBFDPs exhibited visible changes after short-term follow-up. However, these changes did not result in failure.

Poster Session: Lexical effects on 3D color matches in short- and long-term memory.

We report a comprehensive within-subjects study of color memory, using 22 colors widely spaced in 3D color space. 10 observers made isomeric color matches on iPads (method of adjustment, 3D CIELAB-based color palette) when the test color was simultaneously present or after delays = 10 or 300 sec (random block design). To test for lexical effects on color memory, the same observers grouped 1625 Munsell samples before the memory experiment and provided focal colors and unconstrained color terms for the groups. They also named the remembered color after each 300-sec trial. Delay affected every measure of matching performance. Matches were more variable for 10-sec delays than in the simultaneous condition. Simultaneous matches were near the test colors (∆E=2.8), but the distance from the test color (bias) increased for 10-sec delays, generally in the direction of increased saturation, with variation across test colors. These measures increased little between 10 and 300 sec. To test for lexical effects, an "attraction score" measured how much matches were biased by the observers' unique focal colors. Attraction scores for simultaneous matches were near zero, but some colors showed substantial attraction to the focal colors at 10- and 300-sec delays. The 300-sec matches were highly significantly attracted to the focal colors of names provided after each trial. Observers' color idiolect complexity and test color codability were not impressively related to performance at any delay.

Spectral Energy Distributions of Southern Binary X-Ray Sources

The rapid variability of X-ray binaries (XRBs) produces a wide range of X-ray states that are linked to activity across the electromagnetic spectrum. It is particularly challenging to study a sample of sources large enough to include all types in their various states, and to cover the full range of frequencies that show flux density variations. Simultaneous observations with many telescopes are necessary. In this project, we monitor 48 XRBs with seven telescopes across the electromagnetic spectrum from 5 × 109 to 1019 Hz, including ground-based radio, IR, and optical observatories, and five instruments on two spacecraft over a 1 week period. We construct spectral energy distributions and matching X-ray color–intensity diagrams for 20 sources that have the most extensive detections. Our observations are consistent with several models of expected behavior proposed for the different classes: we detect no significant radio emission from pulsars or atoll sources, but we do detect radio emission from Z sources in the normal or horizontal branch, and from black holes in the high/soft, low/hard, and quiescent states. The survey data provide useful constraints for more detailed models predicting behavior from the different classes of sources.

Poster Session: A Simple Method for the Measurement of the Color Matching Functions.

It is well known that colorimetric matching of colors on different media does not ensure that their appearance is the same for everyone. One of the reasons is that there are variations in the color matching functions (CMFs) between observers, and that individual CMFs are different from that of the standard observer defined in CIE. If CMFs can be measured easily for each observer, customized color management will be possible. Traditional methods require the adjustment of the intensities of three primary lamps (R, G, B) which is not easy for naïve observers. A simple method is proposed in this research, in which observers select the closest color from multiple candidates to a reference. The candidate colors are composed of 5 x 5 x 5 lattice, whose center is the expected matching color. The average and standard deviation of the CMFs were calculated based on the CMFs of 11 observers. For each CMF, 5 candidate values were produced: average, average +/- 1/2 SD, average +/- SD. In the experiment, the observers were allowed to choose one for each CMF of RGB among 5 candidates to make a best match. Five observers whose CMFs were measured with the adjustment method participated in the experiment. The results of two methods showed good consistencies for the G and R CMFs, while some discrepancies were observed for the B CMFs. The total time of the experiment was reduced to 1/4 to 1/3, and it was also easy for the naïve subjects, which indicate that our method is an effective one.

Illuminant metamerism between natural teeth and zirconia restorations evaluated with a chromatic adaptation transform

Little is known about the effect of illuminant metamerism between natural teeth and zirconia restorations, despite their increasing clinical popularity. The purpose of this in vitro study was to compare illuminant metamerism between pairs of natural teeth and layered zirconia restorations and pairs of natural teeth and monolithic zirconia restorations under 10 different illuminants and analyze their metameric potential. Spectral reflectance factors were obtained from 10 pairs of extracted natural teeth and layered zirconia restorations and 28 pairs of extracted natural teeth and monolithic multilayer zirconia restorations. Each pair showed a color match that was within the visual threshold for clinical acceptability (CIEDE2000≤1.8). A special index of metamerism for the change of illuminant (Milm) was calculated from the CIEDE2000 color difference equation. Descriptive statistics and the one-sample t test were used to analyze the results for the Milm and for both groups of layered and monolithic zirconia restorations (α=.05). Layered zirconia restorations reached a mean ±standard deviation value for Milm=0.3 ±0.2 and Milm=0.5 ±0.4 for monolithic zirconia restorations (P<.01). The effect of illuminant metamerism between natural teeth and zirconia crowns was weak and generally within the clinical acceptability limit.

Clinical Tooth Color Matching: In Vivo Comparisons of Digital Photocolorimetric and Spectrophotometric Analyses.

This study aimed to compare the tooth color matching of two dental colorimetric methods: the spectrophotometric analysis (SPM) and the standardized digital photocolorimetric analysis (DPC). The color of 60 maxillary central incisors of 30 volunteers (22.5 ± 7.6 years) was analyzed. In the DPC method, tooth photographs were standardized with the eLABor_aid protocol, processed with Adobe Photoshop Lightroom software, and the values of L*, a*, and b* were obtained with a Digital Color Meter software. For the SPM, L*, a*, and b* were measured directly with a handheld spectrophotometer. Data were submitted to paired t-test and Pearson correlation test (α=0.05). Mean color difference between the two methods was calculated with CIELAB formula. All color coordinates revealed different values when comparing DPC to SPM in the same tooth (p<0.0001). Mean color difference (ΔEab) between SPM and DPC was 11.5 ±3.1. A positive correlation was observed for L* (R2=0.73,p<0.0001), a* (R2=0.31, p=0.017), and b* (R2=0.83, p<0.0001). Even though the color coordinate values were different in both methods, they were correlated, revealing that the DPC is a viable alternative to determine the tooth color matching.

Multicolor-tunable biomass thermochromic dyes utilizing tea polyphenols color developer for temperature-controlled linen fabric

Linen, an important industrial crop, is commonly used in the textile field. The development of temperature-controlled linen fabrics is important for the high-value utilization of cellulose-based industrial products. The linen fabrics with color and performance changes controlled by temperature are prepared via the vacuum impregnation process utilizing biomass three-component thermochromic dyes. Currently, three-component thermochromic dyes based on the bisphenol A (BPA) color developer have received special attention due to high saturation color and reversible color-changing performance. However, the toxicity and carcinogenicity of BPA limit its applications in security inks, decorative coatings, plastics, etc. Exploiting excellent and safe biomass color developers for three-component thermochromic dyes remains a challenge. Tea polyphenols (TP) are proposed as alternatives to BPA to prepare the blue, red, yellow, and green three-component thermochromic dyes. According to the laws of subtractive color mixing, multicolor-tunable thermochromic dyes are obtained by color matching of red, yellow, and blue dyes to span multiple shades. Biomass thermochromic dyes are adopted to fabricate temperature-controlled linen fabrics by the vacuum impregnation process. Temperature-controlled linen fabrics can change color reversibly between the original color and achromatic color. The color-changing occurs due to the ring opening and closing of leuco dyes triggered by the solid-to-liquid transition of solvent. The phase transition temperature of the thermochromic dyes absorbed on the linen fabric is 46 ℃. As the temperature increases, the contact angle of temperature-controlled linen fabrics decreases from 129° to 29°, resulting in a change from hydrophobic to hydrophilic with 49 J g−1 of thermal energy stored. The linen fabrics exhibit temperature-controlled changes in color, surface wettability, strength, and thermal insulation. This eco-friendly method with biomass thermochromic dyes for the preparation of color-changing linen fabrics provides a new approach, which is contributing to the development of cellulose-based smart color-changing textiles.

Scanning macro x‐ray fluorescence spectroscopy maps for matching 17th century paintings color areas to different earth pigments uses and for investigating attribution issues

AbstractFe and/or Mn‐containing yellow ochre, red ochre, and umber earth pigments are omnipresent in 17th century paintings. Less common in the materials used in historical paintings of this period is the Fe and Mn‐rich earth pigment sienna. Different uses of historical pigments in one painting by Georg Flegel (1566–1638) and another version of the same painting but of disputed attribution were recently uncovered by means of macro‐x‐ray fluorescence (MA‐XRF) scanning and other non‐invasive analytical techniques. In this paper, an approach solely based upon the correlation of Fe and Mn MA‐XRF maps with the optical image of the painting is compared to the use of Mn/Fe correlation plots. The identification of clusters within a plot of the Fe counts vs. the Mn counts can aid to infer whether an area with a certain color matches with the use of the earth pigments found in the two paintings and to ultimately shed light on the different usage of these pigments. The analytical thresholds found in the Mn/Fe correlation plots allowed to identify clusters differing in composition, which matched an area of a certain color with the earth pigments used therein. This highlighted the differences and similarities between the two paintings, ultimately ascertaining the lower value of the painting of disputed attribution. The analysis of single‐pixel spectra allowed refining the interpretation of specific Mn/Fe correlation plots. The purpose of these data evaluation steps is presented and the limitations of the proposed methodology are also discussed.