> For the complete documentation index, see [llms.txt](https://knowledge.illumina.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://knowledge.illumina.com/instrumentation/novaseq-x-x-plus/instrumentation-novaseq-x-x-plus-reference_material-list/000007970.md).
# Chemistry and Imaging on the NovaSeq X Series Instruments
**Background**
The NovaSeq X Series is powered by XLEAP-SBS chemistry, a faster, higher quality, and more robust update to proven Illumina sequencing by synthesis (SBS) chemistry.
**Chemistry**The NovaSeq X Series uses two-color chemistry, which allows for very fast imaging of the flow cell using blue and green channels at every sequencing cycle.
* Clusters with intensity in **green** only: **T**
* Clusters with intensity in **blue** only: **A**
* Clusters with intensity in both channels: **C**
* Clusters with no intensity/dark: **G**
Please note the following differences between the NovaSeq X Series and other two-channel Illumina platforms:
* The NovaSeq 6000, NextSeq 500/550, and MiniSeq: A channel uses combined Red and Green, and the C channel uses Red only.
* The NextSeq 1000/2000 (Standard Reagents): A channel uses combined Blue and Green, and the C channel uses Blue only.
* The NextSeq 1000/2000 (XLEAP Reagents): C channel uses combined Blue and Green, and the A channel uses Blue only.
**1.5B Flow Cell Layout**
There are 2 swaths per surface (2 top and 2 bottom), 2 surfaces per lane, and 70 tiles per swath for a total of 560 tiles imaged.
**5B Flow Cell Layout**
There are2 swaths, 1 surface per lane, and 98 tiles per swath for a total of 1568 tiles imaged.
**10B Flow Cell Layout**\
There are2 swaths per each surface (2 top and 2 bottom), 2 surfaces per lane, and 98 tiles per swath for a total of 3136 tiles imaged.
**25B Flow Cell Layout**
There are 4 swaths per each surface (4 top and 4 bottom), 2 surfaces per lane, and 98 tiles per swath for a total of 6272 tiles imaged.
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| *For any feedback or questions regarding this article (Illumina Knowledge Article #7970), contact Illumina Technical Support* [*techsupport@illumina.com*](mailto:techsupport@illumina.com?subject=Question%2FFeedback%20Regarding%20Illumina%20Knowledge%20Article%20#000007970%20-%20Instrumentation%20\&body=Dear%20Illumina%20Technical%20Support,%0D%0A%0D%0A)*.* |
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