diff --git a/Photos-version-5-database.md b/Photos-version-5-database.md
index afd8754..794f364 100644
--- a/Photos-version-5-database.md
+++ b/Photos-version-5-database.md
@@ -106,6 +106,19 @@ ZINVITEEHASHEDPERSONID = ?
 LIMIT 1
 ```
 
+### Dates
+For photos, various dates can be found in the following columns:
+- `ZGENERICASSET.ZMODIFICATIONDATE`: on initial import = file modification date
+- `ZGENERICASSET.ZDATECREATED`: EXIF Create Date
+- `ZGENERICASSET.ZADJUSTMENTTIMESTAMP`: blank on import, even if EXIF Modify Date is set
+
+If adjustment made, `ZHASADJUSTMENTS` set to 1 and `ZADJUSTMENTTIMESTAMP` set to time of edit and `ZMODIFICATIONDATE` updated to a time close to, but not exactly the same as `ZADJUSTMENTTIMESTAMP` (in my tests, a few seconds after `ZADJUSTMENTTIMESTAMP`)
+
+Photos modifies `ZMODIFICATIONDATE` even for photos that have not been edited.  This may be the time any data about the Photo was modified by Photos or even photoanalysisd. 
+
+On export, Photos does not set the EXIF modify date.
+
+
 
 **TODO** Document the following