offset on hdr images

hey all!

i took some xyz recordings recently of a venue i need to setup in
i dumped out from openni to aligned xyz/rgb pairs
with xyz stored in hdr, rgb stored in jpg

but when i got home i realised that for some reason hdr isn’t supporting negative values (i.e. anything left or down from the camera)
and all these values have 16 added to them
after some hacking around with some basic algorithms to fix it, it still seems the data is worthless

i’m wondering if i’m missing something somewhere? a flag that enables negative values
for the time being i’m just adding an offset of 16.0f to my xy values when they’re saved

other format suggestions for float images are also welcome
dds is pretty good but freeimage doesn’t support writing them
i’m a little shocked that a hdr image format doesn’t support negative values, but i guess it makes sense for conventional hdr imaging (as opposed to use of hdr in comp graphics)

hmm ok
.EXR seems fine
but the file sizes are 10x the size

i’m thinking it might actually be a little-endian error
as if you input a value of 16 and save, you get back a value of 32 (so not only a negative values issue)
whereas exr is fine, pointing to an issue within freeimage itself