# LabProbe

> Status: Available. LabProbe by GCRflow is a bilingual browser application for CIELAB comparison, device-calibrated CMYK inverse guidance, and multi-round digital-proof color tracking.

Accuracy notice: Delta E calculation requires comparable measurement conditions. CMYK inverse guidance uses the selected device template or the system digital-proof default. Accuracy depends on the actual device, media, RIP, and measurement workflow; final proof measurements remain required.

Canonical application: https://lab.gcrflow.com/
Full factual product description: https://lab.gcrflow.com/about.html

## Intended users

Prepress operators, pressroom teams, and color technicians who need to compare measured and target colors, estimate a CMYK file-percentage adjustment, and retain a traceable job history.

## Verified capabilities

- Inputs: current CMYK percentages, measured CIELAB L*a*b*, and target CIELAB L*a*b*.
- Color difference: CIEDE2000, CMC 2:1, CIE76, and CIE94.
- Workflow choices: unlaminated, gloss laminate, and matte laminate.
- CMYK inverse output: percentage deltas, proposed CMYK values, model-estimated Delta E 2000, K-range status, and total-area-coverage context, using the selected device template or system digital-proof default.
- Digital-proof calibration lab: authenticated users can upload CGATS, TI3, IT8, TXT, CSV, or TSV measurements containing Lab or XYZ. The service auto-detects TC1617 and P2P51, supported portrait/landscape target layouts, and common i1 or Barbieri/Gateway patch mappings; it fills CMYK only when identifiers or reference data prove the mapping, combines up to three repeated scans, and stores merged numeric samples plus source hashes.
- Target separation: TC1617 / IT8.7/5 builds the complete four-channel local-response baseline. When a complete baseline is available, P2P51 measurements can fit a three-dimensional Lab affine maintenance layer over shared CMYK patches and produce an activatable 1,617-patch derived template. P2P51 alone remains a G7/NPDC/drift-verification record and is not represented as full characterization.
- Control: independent C, M, Y, and K channel locks.
- Preview: connected measured/target sRGB screen previews derived from Lab values.
- GCR: a four-channel gray-replacement advisory and ink-saving context when applicable.
- OCR: photo-based recognition of L*, a*, b* from an instrument LCD. OCR runs on the device; the OCR image is not uploaded.
- Records: accounts, press profiles, job numbers, round-by-round saving, closed-loop continuation, final verification, and private cloud history.
- Mobile: installable PWA interface designed for phone use. The cached shell can open offline; solving and cloud synchronization require the service and a network connection.
- Preferences and support: theme, default Delta E formula, service diagnostics, feedback, cache controls, and protected history deletion.
- Languages: Chinese for a Chinese primary browser language; English for every other primary language; manual switching is remembered locally.

## Important limitations

LabProbe is color-workflow decision-support software. It is not a spectrophotometer, a color-measuring instrument, or an automatic press controller. A TC1617 user template supplies a device-specific local response model, but structural validation is not an accuracy certification. The software does not replace calibrated measurement, proofing, pressroom judgment, or final production verification. CMYK and GCR outputs must be validated for the actual substrate, ink, press condition, RIP, and production constraints.

The current system-wide digital-proof default is based on a historical M1 TC1617 data set and is a starting point, not a current-device certification. A TC1617 template or matched P2P51 maintenance template marked ready has passed structural checks only; the status is not an accuracy certification. Independent proof measurements and closed-loop validation remain required.

## 中文摘要

LabProbe 是面向印前和数码样追色的双语浏览器工具，可比较实测 Lab 与目标 Lab、计算色差、按设备模板进行 CMYK 文件反求，并记录多轮追色、最终验收和工单历史。设置页的数码样设备校准可识别包含 Lab 或 XYZ 的 CGATS/TI3/IT8/TXT/CSV/TSV，自动匹配 TC1617、P2P51、横竖版以及支持的 i1 与 Barbieri/Gateway 色块顺序。TC1617 建完整四通道基础；已有完整基础时，P2P51 可生成设备状态维护层，单独上传则只作 G7/NPDC 与漂移复核。当前系统默认来自历史 M1 TC1617 数据，可作为没有个人模板时的起点；最终准确度仍需独立复测与闭环工单验收。