WG 4 – Objectives
Chromatic aberration refers to possible artifacts caused by the wavelength dependency of an imaging system’s optical properties, with the result that two colors arising from the same physical location within the sample appear separated in the image. Such artifacts result from the optical design of the system (e.g., well-corrected versus poorly corrected objective lenses), the manufacturing tolerances of the system components, and the alignment of the optical components.
Co-registration accuracy more generally refers to the system’s ability to co-localize dyes of different wavelengths emitting from the same object within a particular experimental set-up. This can be affected by both the experimental set-up and the system architecture. Working within the assumption that microscope users are ultimately interested in co-registration accuracy, WG4 aims to use sub-resolution and larger multi-colored bead preparations to measure co-registration accuracy. Alternative tools for performing these measurements will also be evaluated. WG4 will compare reproducibility across different laboratories to determine the best protocol.
WG 4 – Co-Chairs
Maria Azevedo
Co-Chair of WG 4 and WG 15
WG 4 - Latest News
Hans Fried1, Roland Nitschke2, Kees van der Oord3, Maria M. Azevedo4,51. CRFS – Light Microscope Facility, German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
2. Life Imaging Center and Signalling Research Centre CIBSS, University of Freiburg, Germany
3. Nikon Europe BV, Amstelveen, Netherlands
4. Advanced Light Microscopy Scientific Platform, i3S – Instituto de Investigação e Inovação em Saúde | Porto, Portugal
5. University of Porto
Accurate multi‑colour imaging requires that signals from the same physical location co‑localise across channels. Chromatic aberration is a major source of spatial error in multi‑colour fluorescence microscopy. Therefore, rigorous co‑registration is essential for reliable interpretation of spatial relationships in biological specimens.
In this workshop, we will briefly explain the key steps of preparing a bead sample for co-registration assessment, show the main considerations for image acquisition (1), and show you how to analyze the obtained images using Fiji/ImageJ (2). We will also demonstrate how specific objective‑related factors can influence co‑registration performance. Finally, we will share practical hints and tips to support routine co‑registration analysis.
(1) Dauphin A., Azevedo, M., et al. Protocols.io, Ensuring accurate co-registration measurement for quality control of Single Point Confocal Laser Scanning Microscopes – V1, dx.doi.org/10.17504/protocols.io.q26g7yrj8gwz/v1
(2) Faklaris, O. et al. Quality assessment in light microscopy for routine use through simple tools and robust metrics. J Cell Biol 221, doi:10.1083/jcb.202107093 (2022).
We are pleased to announce that the QUAREP-LiMi consortium will be presenting five specialized workshops at the upcoming European Light Microscopy Institute (ELMI) meeting. Our sessions are designed to provide researchers with frameworks for improving image quality, ensuring data reproducibility, and implementing rigorous quality control standards in microscopy. The workshops will cover five critical pillars of instrument characterization:
-
The QUAREP-LiMi Tool Kit (WGs 1 & 2):
Discover how to streamline periodic quality assessments. We will present the latest developments in the Tool Kit, including user-friendly software tools for illumination power and stability (compatible with Nikon and Zeiss), as well as its data browser for long-term performance monitoring. -
Detector Performance & Photon Characterization (WG2):
Learn how to transition from "arbitrary digital units" (ADU) to actual photon counts using the Photon Transfer Curve (PTC) method. We will demonstrate protocols for characterizing photon conversion factors, read noise, and dynamic range for both point and area detectors. -
Assessing the co-registration accuracy of a microscope (WG4):
Chromatic aberration is a major source of spatial error in multi‑colour fluorescence microscopy. This workshop will show practical hints and tips to perform routine co‑registration measurement and analysis. -
Point Spread Function (PSF) Analysis (WG5):
This workshop provides a practical guide to PSF measurement—from beads slide preparation and image acquisition to analysis using open-source tools and integration with OMERO for longitudinal monitoring. -
The Light-Microscopy Metadata Model (LiMi-Model, WG7):
In collaboration with BioImaging North America, 4D Nucleome, and OME, we will introduce the LiMi-Model. This framework aims to harmonize the description of hardware and acquisition settings to ensure datasets are FAIR (Findable, Accessible, Interoperable, and Reusable) by design.
We warmly welcome our first member from Nigeria, Dr Olubunmi Ayobami Balogun, from the University of Ibadan who just joined Working Group 1, 4 and 12.
Last meeting: 21st April 2026, 5:00 pm
54th meeting, 21st of April 2026
Meeting date
Meeting summary
53rd meeting, 17th of March 2026
Meeting date
Meeting summary
52nd meeting, 17th of February 2026
Meeting date
Meeting summary
49th meeting, 16th of September 2025
Meeting date
Meeting summary
48th meeting, 17h of June 2025
Meeting date
Meeting summary
46th meeting, 15th of April 2025
Meeting date
Meeting summary
Memberlist WG 4