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Forensic colour assessment · on-device

Colorime3ka: the colour of a skin finding, measured, not guessed

Two doctors describe the same bruise in two different colours. Colorime3ka measures the colour of a finding from a photo or the live camera, names it, and tells you which substance causes it: melanin, haemoglobin, dried blood, or none.

Download on the App Store Manual and support ›
CIELAB · ΔE (CIEDE2000) Atlas of 68 findings LiDAR scale Forensic and dermatological modes No network · no account iPhone · iPad

What decides is the chromophore, not the colour

Not the colour itself, but which substance causes it. Melanin darkens the whole area and keeps a yellow-brown hue. Haemoglobin adds colour but barely darkens the skin, because the blood lies beneath an intact epidermis. Dried blood has a very dark red-brown core. A scar is recognised by what it lacks, no dark component, no skin markings.

Colorime3ka measures the robust colour of the area (median of channels), converts it to CIELAB and names it by ΔE (CIEDE2000). It adds uniformity, sharpness of the margin, surface roughness, outline and the hue gradient from centre to edge. The reticle also frames the surrounding skin the finding is compared with.

Calibration

A grey card removes the colour cast of the lighting; a 24-patch colour chart gives a correction matrix for comparable series. The printed T2/T3 target from the aPrehliadky project is found in the photo automatically.

Millimetre scale

Two taps on a ruler, the target's millimetre fiducials, or on iPhone Pro straight from LiDAR · no ruler needed. The LiDAR scale is not provided when zoomed in: a silently wrong scale is worse than none.

Atlas of 68 findings

Bilingual, with original schematic drawings: mechanical, thermal and electrical injuries, healing, pigmented lesions, efflorescences, post-mortem changes, and findings regularly mistaken for abuse.

Postoperative wound (3.1)

With the context "surgery" and the date of the operation, the app stops guessing what the finding is and describes healing on the Southampton score and the CDC/NHSN definition of infection. Never above grade II from colour: pus and dehiscence are never claimed from a photo.

Reference fingerprints

Recognition thresholds are measured on verified clinical photographs. Expert mode stores a measurement as a further reference: twelve numbers and a note, never a photo; colleagues exchange them as .ch3lab files, and received fingerprints wait in quarantine.

From photo to record

Photo or live camera

Photograph the finding or measure it directly in the camera; an adjustable measurement area with a reticle.

Calibration and scale

Grey card, 24-patch chart or T2/T3 target; scale from a ruler, the target or LiDAR. Length and width can also be entered by hand, in mm, cm or inches.

Clinical context

A photo does not carry what most often decides. The app asks: state of the subject, trauma or surgery in the history, duration, body region, broken skin, blanching under pressure. Impossible combinations are excluded, with the reason stated.

Assessment in two modes

Forensic (bruise, abrasion, wounds, crusts and scars, erythema, vitality) and dermatological (pigmented lesions and ABCDE, efflorescences, inflammatory and vascular changes). Percentages express agreement with features; the ceiling is 85 %.

Record and export

A record that states the source of the scale, and CSV export of every measured quantity with the conditions under which it was obtained: for documentation and research.

What the app does not do

Colorime3ka gives no diagnosis and is not a medical device. It does not date a bruise from its colour, and says so openly: colour charts assigning a number of days have not held up in newer studies, and only the yellow component has support in the literature: it is not seen in bruises younger than about 18 hours. The ABCDE criteria appear as published educational criteria for a clinician; the app never states whether a lesion is malignant. A 12-page professional manual in Slovak, English and German comes with the app; since version 3.3 the whole app is also available in German.

PlatformiPhone, iPad (iOS/iPadOS 17+); LiDAR scale on iPhone Pro
MeasurementCIELAB, ΔE (CIEDE2000), tonal components, texture, outline
Atlas68 findings with original drawings, SK/EN/DE
ExportCSV (every quantity), .ch3lab (reference fingerprints)
Priceone-time purchase on the App Store, no subscription

Privacy first

Colorime3ka is a research and decision-support tool for qualified professionals: not a medical device, and it does not provide a diagnosis; the final assessment always belongs to the physician. Created by Ján Šikuta, MD, PhD, forensic pathologist.

Frequently asked questions

Can Colorime3ka tell the age of a bruise?

No. Colour charts assigning a number of days have not held up in newer studies; only the yellow component has support in the literature, and it is not seen in bruises younger than about 18 hours. The app says so openly instead of estimating an age.

Do I need a calibration card?

It is not required, but it helps a lot. A grey card removes the colour cast of the lighting, a 24-patch chart gives a correction matrix for comparable series, and the printed T2/T3 target is found in the photo automatically.

Can I measure the size of a finding without a ruler?

On iPhone Pro, yes: LiDAR measures the distance to the measured point and turns it into a millimetre scale. Otherwise two taps on a ruler or the target's millimetre fiducials are enough; length and width can also be entered by hand.

Are photos sent to a server?

No. The app has no networking layer, collects no data, and photos and measurements stay on the device unless you export them yourself.

Is Colorime3ka a medical device or a melanoma detector?

No. Percentages express the agreement of measured features with reference criteria, not diagnostic certainty, and the ceiling is 85 %. The ABCDE criteria are shown as educational criteria; the decision always belongs to the physician.