adding standard metadata with xattr

I was wondering why I could not add common metadata with xattr after losing metadata processing pictures with sips

tell application "Finder" to set sel to item 1 of (get the selection) as text
set {pxH, pxW, getDpi} to get_pictprops(sel)

return do shell script "mdls '" & POSIX path of sel & "'"
#do shell script "xattr -w com.apple.metadata:_kMDItemUserTags '(\"orange\\n6\",\"test\")' " & a
do shell script "xattr -w com.apple.metadata:kMDItemPixelHeight '" & pxH & "'" & quoted form of POSIX path of sel
do shell script "xattr -w com.apple.metadata:kMDItemPixelWidth '" & pxW & "'" & quoted form of POSIX path of sel
do shell script "xattr -w com.apple.metadata:kMDItemResolutionHeightDPI '" & getDpi & "'" & quoted form of POSIX path of sel
do shell script "xattr -w com.apple.metadata:kMDItemResolutionWidthDPI '" & getDpi & "'" & quoted form of POSIX path of sel

on get_pictprops(getFile)
	#get measures for single images
	set px to POSIX path of (getFile as text)
	set get_pp to paragraphs -2 thru -1 of (do shell script "sips -g pixelHeight -g pixelWidth '" & POSIX path of getFile & "'")
	set {pxH, pxW} to {word -1 of item 1 of get_pp, word -1 of item 2 of get_pp}
	
	set getDpi to (word -1 of (do shell script "sips -g dpiHeight '" & px & "'") as integer) div 1000
	return {pxH, pxW, getDpi}
end get_pictprops

(*
kMDItemPixelHeight                 = 2000
kMDItemPixelWidth                  = 1815
kMDItemProfileName                 = \"sRGB IEC61966-2.1\""
kMDItemResolutionHeightDPI         = 300
kMDItemResolutionWidthDPI          = 3
*)

Unless it’s an odd image format, I suspect the Spotlight filter reads most, if not all, of those values by inspecting the image itself, without any recourse to xattr files. Have you tried simply reindexing?

Indeed, I confirm. Spotlight isn’t able to read Metadata of freshly created files, mdworker doesn’t work that fast

After awhile Metadata becomes available for spotlight