ORWO EU2 glass plates info?

Hello fellow creatures. I've come into possession of a pack of said glass plates and was wondering if you'd know the emulsion speed and suggest a developing time/chemical. There are only 12, so that's why I'm reluctant to go on an experimentation spree.

With a bit of google translate help I see only one reference to the speed. iso 5, and that was qualified "Technique - kodak bellows without the viewfinder of the early twentieth century glass plates 6x9cm + EU2 iso ORWO not know how much but I think the 5"
These were originally for an electron microscope so perhaps looking at how one would use them for their intended purpose would give you an idea of how to use them alternatively.

Orwo EU2 is a spectrally unsensibilized plate designed for electron-microphotography.

3-4min in MH 28 1+4
4-5min in A 71
1-2min in A 37

Unsensitized I guess means that it is blue and uv-sensitive, thus the slow speed?

Yes and no.
It means that it is basically only UV (to some extent) and blue sensitive.

The degree of spectral sensitization does not influence speed in first instance, though spectral sensitizing is used in some cases to crank up speed with a otherwise unchanged emulsion.

Orwo made several emulsions for electron microphotography including one fast one.

Yes, you are right AgX - I was typing too fast and thinking too slowly.