# Changes in how background subtraction is done

**URL:** <https://www.rubin.community/t/changes-in-how-background-subtraction-is-done/756>\
**Category:** DM Notifications\
**Tags:** dm-dev\
**Created:** [May 5, 2016, 12:10am UTC](https://www.rubin.community/t/changes-in-how-background-subtraction-is-done/756 "2016-05-05T00:10:57Z")\
**Posts on this page:** 1\
**Showing post:** 3

<div class="post-metadata">

**Author:** ![rowen](https://sea2.discourse-cdn.com/flex002/user_avatar/www.rubin.community/rowen/32/52_2.png) [@rowen](https://www.rubin.community/u/rowen)\
**Post date:** [May 5, 2016, 3:35pm UTC](https://www.rubin.community/t/changes-in-how-background-subtraction-is-done/756/3 "2016-05-05T15:35:58Z")

</div>

I don’t think it was a particularly good feature; this value is passed to C++ code, which expects string values (of which “NONE” is one supported and documented value).

Furthermore, as the reviewer @price pointed out, the substitution was made in the `validate` method, which should not change values. If we are going to restore it, it should be restored in some other way.

---

_[View the full topic](https://www.rubin.community/t/changes-in-how-background-subtraction-is-done/756)._