# Issues with OD/temp measurements **URL:** \ **Category:** Experiments\ **Created:** [August 20, 2019, 3:44pm UTC](https://www.evolver.bio/t/issues-with-od-temp-measurements/129 "2019-08-20T15:44:52Z")\ **Posts on this page:** 1\ **Showing post:** 21
**Author:** ![bgwong](https://yyz1.discourse-cdn.com/flex035/user_avatar/www.evolver.bio/bgwong/32/262_2.png) [@bgwong](https://www.evolver.bio/u/bgwong)\ **Post date:** [October 10, 2019, 7:12pm UTC](https://www.evolver.bio/t/issues-with-od-temp-measurements/129/21 "2019-10-10T19:12:15Z")
The signal increases up to a certain extent, and then it decreases after the culture gets too dense and starts to decrease in value. Here is an older post that gives more information: > [@OD measurements with two photodiodes?](https://www.evolver.bio/t/od-measurements-with-two-photodiodes/99): > > Summary I’m looking for some advice on how to properly do calibrations with two variables. Background I’m trying to integrate hardware configuration for OD measurements to improve the consistency and dynamic range of the sensors. I figured adding a different sensor at a different LED-diode offset would do the trick. I did a simple, rough experiment and collected measurements off of 90 degree and 135 degree offsets with increasing amount of milk (to approximate scattering from cells). Heres t… --- _[View the full topic](https://www.evolver.bio/t/issues-with-od-temp-measurements/129)._