# Offset and HyD Detectors? **URL:** \ **Category:** Software\ **Tags:** confocal\ **Created:** [June 12, 2021, 2:28am UTC](https://forum.microlist.org/t/offset-and-hyd-detectors/1435 "2021-06-12T02:28:28Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![phoTONIcs](https://avatars.discourse-cdn.com/v4/letter/p/45deac/32.png) [@phoTONIcs](https://forum.microlist.org/u/phoTONIcs)\ **Post date:** [June 12, 2021, 2:28am UTC](https://forum.microlist.org/t/offset-and-hyd-detectors/1435/1 "2021-06-12T02:28:28Z")
Probably a dumb question… but why is Smart Offset disabled for HyD detectors? If zero values are not good for PMTs, then why are they allowed for HyDs? ---
**Author:** ![oQQQQQ8](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.microlist.org/oqqqqq8/32/1030_2.png) [@oQQQQQ8](https://forum.microlist.org/u/oQQQQQ8)\ **Post date:** [June 17, 2021, 5:10am UTC](https://forum.microlist.org/t/offset-and-hyd-detectors/1435/2 "2021-06-17T05:10:05Z")
The bottom half of the HyD is solid state and does not leak current like a PMT circuit does. The need for PMT offset is to delete this current, so you only record signal changes due to the arrival of light. Since HyD detectors have a fixed and steady zero, no offset correction is needed. I must say that I would have preferred that HyD detectors started at 1 instead of zero, as the sea of green can be distracting compared to a black background, when using the QLUT feature. Leica could easily do this on all-HyD systems with a simple substitution of color palette. But in mixed systems, you need to see how much zero you are getting when tweaking the PMT offsets. ---
**Author:** ![phoTONIcs](https://avatars.discourse-cdn.com/v4/letter/p/45deac/32.png) [@phoTONIcs](https://forum.microlist.org/u/phoTONIcs)\ **Post date:** [June 18, 2021, 5:32pm UTC](https://forum.microlist.org/t/offset-and-hyd-detectors/1435/3 "2021-06-18T17:32:44Z")
Thanks for your reply!