Free collection of downloadable images to validate colocalization

Dear Colleagues,

We created a collection of images to test and validate the degree of colocalization of markers in fluorescence microscopy studies.

The Colocalization Benchmark Source (CBS) is a free collection of downloadable images. It consists of computer-simulated images with exactly known (pre-defined) values of colocalization ranging from 0% to 90%. They can be downloaded as sets as well as separately.

The database is available at:

These benchmark images can be used as reference points when quantifying colocalization in dual color fluorescence microscopy studies. The use of CBS will help to obtain more accurate and reliable information in quantitative colocalization experiments and, ultimately, improve understanding of the biological applicability of colocalization observations.

When you employed CBS images for reference in your publication(s), please let us know about it so that we can provide links to your paper(s) and results.

We are working on extending this database and its examples and we encourage fellow scientists to submit examples of their own images when CBS was used to validate colocalization. Please make sure to contribute to CBS by submitting your images at:

If you have any questions, do not hesitate to ask.

Best wishes,

Vadim Zinchuk