Identify internal door as Veneer or Foil

The internal doors I have are from the 80's when house was built, been told they are Danish doors as the handles, locks and hinges are danish.

How do I define if they are veneer or foil etc. I can see they have a typical wooden frame not mdf etc. Also I can see the skin being approx 3mm ply/hardboard looking at the top or bottom of the door with a pine look finish.

So how can I define which they are.

As an alternative can these doors be machine sanded using a random orbital sander to re-varnish.

thanks

Not my area of knowledge but maybe if they are foil (might be metallic) running a pipe finder over the door might register metal, it works that way on foil backed plasterboard.

I thought foil (printed paper with a thin clear plastic layer bonded onto it) came in a bit later than that as it requires vacuum pressing to schieve it. I doubt that it matters much as the finish veneers being used on lower priced doors by the 1970s were down at the 0.3 to 0.4mm thickness range which is damned nigh impossible to sand without going through. Fire doors generally have a thicker veneer facing and are not normally foil wrapped

Are the doors hollow core or solid core? Either way the door will normally ccomprissa core ("eggbox" or chipboard) with lock and hinge blocks in solid material (if hollow core) and a softwood edging around that. To either face of that is bonded a plywood, hardboard, MDF facing which is veneered or foil wrapped on the outer face it may or may not have a hardwood lipping applied to the two vertical edges or possibly all 4 edges. So.any chance of a photo showing the lock edge of tbe door together with the top edge of tbe door? Looking to sre how the door edge detail is done

Another clue might be found if you take one handle and escutcheon off. Where the door has been drilled it might be possible to ascertain the surface type - veneers, even thin ones, have a more ragged edge where they have been drilled than paper

Are there such things asd foil wrapped internal doors, other than those hanging on kitchen units?

Yes. They were generally hollow core. You don't see them these days.