GUEST: So this is an Escher print that my grandfather had bought, and uh, gifted to my parents when they lived in Holland before they moved to the States and where I was born. It's a signed and numbered print which includes a letter that is, uh, written by Escher addressed to my grandfather.

APPRAISER: Yes. Th-this is really unusual for us to have an accompanying letter signed by the artist. It's dated 1953.

GUEST: Right.

APPRAISER: And he completed this print in 1951; so shortly thereafter. It's on his letterhead. We're also fortunate to have a friend who spoke a little Dutch tell us that this last line refers to having met your grandfather at an exhibition. A wonderful provenance.

GUEST: Yeah.

APPRAISER: That your grandfather met the artist, enjoyed his work at the show, was able to acquire work at a time when Escher was becoming known in Holland, but was not known so much internationally. And this print is instantly recognizable, of course, as Escher. It's typical Escher, but it's also a little unusual, which makes it special. Usually in Escher, you have the repeating forms of the same object. So a-a fish will interlock with another fish and a repeating pattern.

GUEST: Right.

APPRAISER: Here we have this wonderful menagerie of creatures. But what's unusual is it's not the same repeated pattern.

GUEST: Right.

APPRAISER: And Escher was actually experimenting here because he really wanted to try to do one of his forms with different objects, different shapes that would interlock. And there's six different forms on each side. So you have 36 different pieces.

GUEST: Hm. Okay. That-that explains the name of the piece, too. I know it's called "Filled Plane II," so.

APPRAISER: Yes. Well, he did do two versions of Plane Fill, but we also know from this letter that he refers to it as a-a mezzotint.

GUEST: Yeah.

APPRAISER: And I can also tell that this is a mezzotint by the structure of the print. So mezzotint is an ancient printmaking technique developed in the late Renaissance, where the copper plate was burnished so it would print completely black. A mezzotint rocker would mark up the plate with little pits that would collect the ink.

GUEST: Okay.

APPRAISER: And then the artist would burnish away and create the positive form, so from black to white. In the 1950s, Escher started experimenting with mezzotint. It's dated at the top, March 1951. And that tells us that this is not number two, but number one. Number one is the first print he made of this composition. And that is the mezzotint. Number two was the lithograph he did a couple years later. So we know this is Plane Filling I, by MC Escher, Maurits Escher, and we can see that here it is signed and numbered "Escher" and "37 of 50." And these mezzotints are highly desirable from collectors.

GUEST: Hm. Oh.

APPRAISER: We were hoping to see maybe some indication in your grandfather's letter of how much he might have spent to purchase this print.

GUEST: I do not know, it's, um, the handwriting is, uh, old-fashioned enough (chuckling): that I can't read it.

APPRAISER: Yes, and-and we couldn't see any numbers. And so at auction today, with a conservative estimate, I would put this at $20,000 to $30,000.

GUEST: Wow. That's, that's impressive.

APPRAISER: And I would put the letter at about $400 to $600.

GUEST: All right.

APPRAISER: Just, just for the Escher collectors.

GUEST: Sure.

APPRAISER: But I'm sure it's not going to be separated from this print.

GUEST: Yeah.

APPRAISER: It's been with your family now for three generations.

GUEST: And we plan for the fourth.

APPRAISER: Yeah. Absolutely, that's amazing.