Corrections on a copy lens: -3 ,-8 ,+4, +4, +12

[Embdude]

Can someone please explain the significance of the correction number on a copier lens?

As an example of what I am asking about there is an auction on ebay with a similar but not quite identical lens set...

"5 Bausch & Lomb (B&L) copy lens set with mount. They are all the same lens: 209mm F4.5 BUT they have different visual corrections. Corrections on the lens: -3 ,-8 ,+4, +4, +12"
https://www.ebay.com/itm/26500101100...rEeqDADhx1iSqY

Are these correction numbers common to copy lenses and what do they mean?

Thanks

[Bob Salomon]

Don’t you mean a copier lens?

[Embdude]

Don’t you mean a copier lens?

Probably. I do not know the proper terminology I'm afraid, but I'm willing to learn.
Copy camera, Process lens, Copier lens, Projection lens, Enlarging lens, are these describing specific designs or just describing the intended use, or both?

[Bob Salomon]

Probably. I do not know the proper terminology I'm afraid, but I'm willing to learn.
Copy camera, Process lens, Copier lens, Projection lens, Enlarging lens, are these describing specific designs or just describing the intended use, or both?

Specific lenses for specific uses.

[Embdude]

Thanks Bob. So the +/- corrections are these something specific to copier lenses or are would they also be used on process or other types of lenses?

[Bob Salomon]

Thanks Bob. So the +/- corrections are these something specific to copier lenses or are would they also be used on process or other types of lenses?

Probably a setting for technicians working on the copier.

[xkaes]

One more possibility -- I can't see the picture, EBAY can't find it -- Fujinon EFC lenses for photo processing machines (developing & printing) have similar number -- without the + / - , from 1 to 15, for example. They are not aperture settings. They are distance settings, perhaps for particular machines or film formats, etc.