THE BLOTTER BARN: San Francisco’s Hidden LSD Museum

3466 20th St, San Francisco, CA 94110

San Francisco is a town that's lost its freak flag in recent years, but that message certainly didn't reach Mark McCloud and his glorious collection of 30k hits of acid. You see, in a City well-known to have forgotten its past in order to build a brighter (but lamer) future, Mr. McCloud has found a unique way to fully preserve the glory days of the hippy era and he's creating some pretty gnarly art out of it.

And it all lies here, at 3466 20th St, in a decrepit Victorian mansion in SF's Mission district. Passerbys have no idea what goodness lies behind these hollow walls; they wander by, sipping their lattes en route to visit the 'Full House' house, thinking "Therein probably lies another tech douche bag" but in reality, they have no clue what illegal artistry lies within...lots and lots of LSD!

And before you dive down the rabbit hole, I must add that this is one of those "you're going to their house" kind of excursions. There's no sign, no proper entrance, no ticket taker and no regular hours. This isn't a public museum by any means, it's simply one man's decades-old collection of drugs, displayed all over the first floor of his home. The un-adventurous need not apply in these parts.

If you're lucky enough to connect with Mark for a visit, ring the doorbell and prepare yourself to party like it's 1974 all over again. The inside is an incredible time capsule dedicated to all things LSD. In fact, everywhere you look you're reminded that one lick in the wrong place will send you to wacky town. Also, this is the part where you meet Mark, which is where the fun really starts.

A colorful character, to say the least, he's exactly what I wanted to experience from a guy who's been collecting acid tabs for decades and making trippy art out of them. 

A real warm gentleman, with an infectious laugh and wild stories for ages, Mark is a guy who's hung out with the likes of Timothy Leary, Abbie Hoffman and almost every radical from back in the day. A one-time producer and enormous advocate of the positive effects LSD, he's actually evaded serious trouble with the law (he cops to having "a great, and busy, lawyer") serval times over the last few years. Plus, he's walked the walk and has claimed to have tripped thousands of times, a feat which I 100% believe after spending some time with him. Dude is something special, but you'll need to keep up with him.

Now, let's get to his art. It's glorious, fascinating and very unique to the eye.

What aligns Mark's walls are a couple hundred amazing pieces of acid art. What is acid art, you ask? Well, it's simply intricate designs and cool patterns made entirely from acid tablets.

They look basic from afar, but if you get up close/personal, you can see all of the meticulous tablets welded together to make each design. There are some really unique pieces here, many which were numerically labeled by the DA's office to indicate how many tabs make up each.

And each piece has its own flavor and style, which helps Mark distinguish the dealer origin/era which it was created. So with him as your trusty guide, the best thing to do is just gawk, find hidden things and ask lots of questions.

Mark MIGHT have an answer.

You'll also come across some amazing artifacts from his life and times, which include: an awesome photo of Mark with Timothy Leary, some family portraits from the early 20th century, his acid making kits, and all kinds of cool artifacts from the Sunshine era.

And once you're done snooping around, you'll sadly leave your makeshift 1974 and re-enter a San Francisco that has no time or place for this kind of thing anymore. For shame, SF!

In all, this is an incredible experience; a magical journey and a total throwback to a simpler time. Props to Mark for keeping this gem alive and being the character that he is. What a trip.


From what I can piece together chatting with Mark, he's been making blotter art for over 30 years and his work has been featured in galleries all over the US.

Born in Detroit, but raised in Buenos Aires, Mark spent his formative years at a boarding School in Claremont CA. After trying the "sunshine" at age 13, Mark finally realized there was a "higher calling" in life and started collecting the stuff for cataloguing. Once acid imagery became a thing in the late 60s, Mark was open for business.

After almost dying during an accident while on LSD in 1971, Mark really got finally got really serious about his work, ultimatley moving into the home you see today (which he purchased in the early 80s, smart real eastate move...) and curating the largest collections of acid art in the World

The reason for turning this hobby into a full fledged life business? I think McCloud's interview with VICE sums it up perfectly:

At first I was keeping them in the freezer, which was a problem because I kept eating them. But then the Albert Hofmann acid came out, and then I thought, Fuck, I’m framing this. That’s when I realized, Hey, if I try to swallow this I’ll choke on the frame.”