# Chemistry and Imaging on MiniSeq
Two-channel SBS simplifies nucleotide detection by using two fluorescent dyes and two images to determine all four base calls.
Images are taken using red and green filter bands. Thymines are labeled with a green fluorophore, cytosines are labeled with a red fluorophore, and adenines are labeled with both red and green fluorophores. Guanines are permanently dark.
The MiniSeq, NextSeq 500/550, NextSeq 1000/2000, and NovaSeq 6000 Systems use two-channel chemistry.
For more information, see [SBS Technology Spotlight](https://www.illumina.com/content/dam/illumina-marketing/documents/products/techspotlights/cmos-tech-note-770-2013-054.pdf) and the Sequencing by Synthesis page [here](https://www.illumina.com/science/technology/next-generation-sequencing/sequencing-technology/2-channel-sbs.html).
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