GUEST: I actually got this in the San Francisco Bay Area when I was 16 years old.

I was what they called a weekend hippie... (laughs) ...and would go over there on the weekends.

I just started collecting posters and put 'em up in my bedroom, and I still have 'em.

I pa, packed 'em away and just kind of forgot about 'em.

APPRAISER: When I first saw this poster, it immediately caught my eye, because it's quite an unusual poster for the period.

It's a Janis Joplin poster.

APPRAISER: It was for a concert that she performed in in Sacramento on the 27th of March in 1969.

GUEST: Okay.

APPRAISER: Which is only just a few months before she famously appeared at Woodstock, in August.

She's an iconic star in that she really came to the forefront in the late '60s.

She was in a band called Big Brother and the Holding Company.

GUEST: Right, yeah.

APPRAISER: And then she went out on her own.

And that's when she really became hugely successful.

But what really struck me about this poster is that it's a photographic poster.

The posters from this period, the psychedelic posters that came out of the Bay Area in the late '60s...

GUEST: Mm-hmm.

APPRAISER: ...are predominantly graphic, illustrated posters, whereas this is quite unusual.

It's a photograph by Thomas Weir.

It's a great photograph of her.

GUEST: Uh-huh.

APPRAISER: And the other thing that really caught my eye is that I hadn't seen one in person ever before.

It's an extremely rare poster.

There was only one that I could find that has ever sold at auction.

So it really is an unusual piece.

APPRAISER: And I think it really appeals to collectors to have something with a photograph of her on, because she had a very short life.

GUEST: She did, yeah.

APPRAISER: She, she tragically died at only 27 years old.

APPRAISER: So anything of hers, memorabilia of hers, is very sought-after because of that.

APPRAISER: Yours, I've noticed, does have a few tears.

It's got some pinholes.

GUEST: Okay.

APPRAISER: Um, there's a few dings.

APPRAISER: So that does affect the value a little bit.

But because it's such an unusual poster, it, it doesn't make a huge difference to the value.

And I think collectors are quite forgiving of the condition because it's so rare.

GUEST: Uh-huh.

APPRIASER: Do you remember how much you paid for it at the time?

GUEST: For this one, I think I paid a top dollar of about $3.25.

(both laughing) APPRAISER: That's amazing.

GUEST: Yeah.

APPRAISER: Which is pretty in line with, actually, what you would have paid here.

Because it's so rare, you'd probably be looking around $2,000 to $4,000 at auction.

It's a very nice poster.

GUEST: Oh!

APPRAISER: It's a very nice poster, indeed.

GUEST: Wow!

APPRAISER: Um, I'm so happy that you brought it in, because, as I said...

GUEST: Thank you.

APPRAISER: ...I've never seen one before.

GUEST: Thank you-- I'm, I'm glad I was able to bring it in and have you take a look at it.

It's amazing, huh?

APPRAISER: Yeah.

GUEST: $3.25?

APPRAISER: Uh-huh.

I know.

GUEST: Oh, my goodness.

(both laughing) GUEST: That's unbelievable.