Hello,

I have no idea whether this will help; my skills with photo enhancement are quite basic.

I've picked out the date elements and reversed the images, which sometimes helps.  You can see it here:  https://1drv.ms/u/s!ArDsmPjxWZLFkleD6lyuhs8Xem3c

You can zoom in on the image.

You are definitely correct about the month being Sivan.  The date of the month looks to me like it could be kaf-daled, 24.

The year is definitely a challenge.  It appears to me that the 4th character is a glyph, a combination of lamed-fey-kuf, which stands for lifrat katan, and often follows the year (to show that the leading '5' is omitted).  This leaves 3 characters for the year, the first two of which appear to be taf-resh, putting the year into the 5600's.  The third character would therefore either have to be a low number, 1-9, or a number that is divisible by 10. 

I realize that this is only slightly helpful, and hope others will be more successful than I.