Wednesday, November 30, 2011

Elfshot Wants Back In

Maritime Archaic Ground Stone
Elfshot is creeping its way back into my routine.  I still have a lot of writing and analysis left from the summer so I can't afford more than a few hours in the evenings and weekends to work on artifact reproductions or jewelry, but hopefully early in the new year I'll be back in the workshop full time.  In March, I'll be returning to Alberta to help deliver the Archaeological Society of Alberta's flintknapping workshop in Calgary and do a presentation for the Society's Medicine Hat chapter.

Maritime Archaic Indian ground stone artifact reproductions. Gouge/Adze celt and hafted axe (argillite), Lance (slate), plummet (soapstone)
This past weekend I made a double-bitted Maritime Archaic Indian gouge/adze for a (very patient) customer, and the weekend before that I prepared a traveling ground slate kit for a kid's ulu-making workshop delivered by Labrador CURA researchers.  In the meantime, I've been filling Christmas jewelry requests as best I can and working on quotes for Spring 2012 work.  Its too early to go into detail, but I'm very excited to have some major projects in the works with national and international museums, universities, and parks.

Photo Credits: Tim Rast

Sunday, November 27, 2011

Modelling Artifacts in Autodesk 123D Catch Beta

Ground Stone Gouge Rendered in Autodesk 123D Catch Beta
One of the challenges of making a good artifact reproduction is coming up with good reference materials.  A photographic plate in a published report rarely has enough information for me to work from and its not always possible to have the actual artifacts on hand while I make a reproduction.

A dirty job
I usually need to see the object firsthand and take a set of photos and measurements, but there are always questions that come up as the work progresses.  When I heard about the free 3D photo editing software called Project PhotoFly a few weeks ago, I was eager to try it out on artifacts.  In theory, I'd be able to transform a set of 2D photos into a fully rendered 360 degree computer model  that I could then manipulate and view at home.  There needs to be separation between the dust of the workshop and the cleanliness of the lab and this could help bridge it.

The blue wireframes of Project PhotoFly are gone in 123D Catch
Project Photofly is now called 123D Catch Beta and there have been some minor changes in how it works, but its still free, fast, and powerful.  123D Catch Beta takes a folder of 40 or 50 photos and processes them into a 3D model.  It works with objects, room interiors, building exteriors and even people.  I want to use it to create free floating 3D models of artifacts from digital photos.  So far, I can do that, except for the free floating part.

Trimming leaves holes
In the models that I've been able to make, the objects stay fixed to the surface they were photographed on.  Its possible to trim around the artifact so that you don't see the table or pedestal that its sitting on, but that leaves a hole in the object where it made contact with the surface.

Fly-through animations of the model can be exported to youtube, like this one:

The model shows the camera's position for each reference photo
I thought that I'd be able to make a complete 3D object by moving the artifact around to take photos of it from all sides, but that doesn't work.  The program reads all of the information in the photo while assembling the 3D model and gets very confused if the object in the foreground changes, but the background stays the same.  The software is designed to work with fixed objects and a photographer moving around and taking many images of that stationary scene from multiple angles.  Perhaps a completely neutral background without any shadows could allow you to rotate the object and keep the camera in a fixed position, but I don't have the set-up to attempt that.

I had decent results on the weekend taking photos of a reproduction ground stone gouge in my living room.  I mounted the gouge on a glass candlestick so that I could get photos of its underside.  Making this model taught me how important the set up and initial photography is.  The software is capable of quickly and accurately rendering a detailed model from good photography, but I found making changes to that model after the initial rendering much slower and more limited.  The models, called "scenes" in 123D Catch, are created on a remote server and then downloaded to your computer.  On my machine, it takes about 10 minutes to go from a folder full of photos to a 3D scene.

Manual stitch gives the illusion of control to the user
The scene can be rotated, zoomed, cropped and exported as an animation.   Missing or poorly fit images can be manually stitched into the model and then re-submitted to the server and a new model with the new information will be rendered.  The manual stitch option is good to include, but it sucks up time and I found it was quicker and easier to just re-shoot the missing photos and try building the model from scratch again.  For practical purposes, the only post-rendering scene manipulation that the software offers is cropping.  If the shape of your model doesn't look right after the initial render its very difficult to improve it through editing.  And be careful with your cropping - there isn't an undo button.  Seriously, why isn't there an undo button?

As good as the photos you feed it
Autodesk 123D Catch Beta is powerful at rendering images into a 3D scene, but limited in its editing functions.  In order to make better models you need to set-up and take better photos and not count on being able to manipulate the scene within the program.  If the goal of the Beta version is to prove the concept and create a desire for a fully functional 3D photo editing suite, then I think 123D Catch performs perfectly.

Photo Credits: Tim Rast, screen captures from Autodesk 123D Cactch Beta and Project Photofly.

Friday, November 25, 2011

Polar Bear Watch Scotch

Polar Bear Monitoring my Scotch
We had one polar bear hang around the camp towards the end of the season this summer.  It was a young, curious male, who kept wandering back around for another look and another sniff to see what we were up to.  On the first night that the bear showed up the camp manager instituted a 24 hour bear watch.  I was on the midnight to 3AM watch and two other archaeologists had the 3AM-6AM shift.  It was cold and dark and the three of us agreed to use our extra three hours worth of pay to buy a nice warm bottle of scotch.

This fellow swam up and hung around for a few days.

At least one of us got some rest.

Checking out his tracks
I picked up my bottle in Frankfurt at the airport's duty free shop on the way home from our Spain/France vacation.  I thought my 3 hour bonus would stretch a little farther than usual there and I picked up a bottle of 21 year old Ballantine's.  I haven't opened it yet, so I can't comment on the flavour, but I do enjoy the more affordable Ballantine's blend available at the NL Liquor stores.  Unless something else comes up, I'm thinking that I'll have my first taste to celebrate finishing the report.

Lori loves that our living room is turning into a den. 

Photo Credits: Tim Rast

Wednesday, November 23, 2011

I Don't Miss Mosquitoes

Our 2011 Christmas Card?
Every day I'm going through photos from the summer to illustrate the report and it's making me nostalgic for the field.  Unfortunately, there are many more dull, winter months ahead before summer rolls around again.  For the moment, I'm going to try to focus on one of the few negatives of doing fieldwork in the Arctic, to try to keep the itch away for as long as possible.  The fact of the matter is that the mosquitoes in Nunavut during July can make working outside miserable.

They're hard to escape.

I wanted to use this photo recently, but there's a bloody big mosquito obscuring part of the tent ring.
I recall feeling particularly crazy on this day.

On windy days, they might not be flying and biting, but they are there among the pebbles to photo-bomb your artifact shots.
Photo Credits: 
1: Derrick LeGrow or Corey Hutchings (sorry, I can't recall who took the pic for us)
2,3,5: Tim Rast
4: Lori White

Sunday, November 20, 2011

A Trip to Lascaux

Actually, its Lascaux II... the original cave has been closed to the public since 1963.  Over 11 years between 1972 and 1983 an exact replica of two of the main galleries of Lascaux was created a couple hundred metres away from the main cave.  Lascaux is one of the smaller caves containing paintings, but its one of the most spectacular.  Its one of very few caves that has polychromatic art, in fact, one of the figures uses 12 colours.  Again, photos aren't allowed inside Lascaux so I don't have photos of the cave are, but you can experience Lascaux's incredible virtual tour here.

The drive from Rouffignac Cave to Lascaux is beautiful. 

The site is on a wooded slope.  It reminded me of every Provincial campground I've ever visited.
The paintings in the cave are 17,000 years old.

Like all of the sites we visited, the interpreter was fantastic.  he didn't just have a few facts memorized, he was passionate about the site.  He stressed that the paintings at Lascaux were not left by cavemen, but by artists building on 15,000 years of artistic tradition and experience.

The entrance to the replica cave.  The million or so visitors to the actual cave between its discovery in 1940 and its closure in 1963 caused severe, although unintentional, environmental damage to the interior of the cave and the paintings.  The replica cave was a very good compromise.  The placement of the painted figures on the contours of the cave walls is a very important part of understanding and appreciating them.  Seeing them on a flat surface doesn't do them justice, they were meant to be experienced in three dimensions.
Coming out into the daylight again.

Most of the animals on my cave art tattoo are from Lascaux.  Here I am standing in front of a sign at the site.
Of course, I realized too late that its actually a sign to the Lascaux toilets.  What chance do I have of understanding Upper Paleolithic art?  I can't even  interpret pictographs from the past decade correctly.  Sigh.
 Photo Credits: 
1, 8, 9: Lori White
2-7: Tim Rast

Friday, November 18, 2011

How to cheer up a Sarlat wall dog

Photo Credits:
1: Lori White
2-6: Tim Rast

Wednesday, November 16, 2011

Working with Photos

4 pictures = 4000 words, right?
At work, I'm going through photos from the summer's archaeology field season and plugging them into the final report.  I need to review the photos, because there is still writing and analysis that needs to be done for most of the sites and the photographic record is an important part of understanding and reporting the sites.  While I'm doing that review, I figured I might as well pop some of the photos into the report at the same time. I like watching the page number go up on the report and this is one of the easier ways to make that happen.

Recording photos
Of the thousands of photos that I took this summer, about 725 made it into the official photolog.  In the field, the photolog was a little white survey book that we recorded the photo number, date, site, direction, camera used, photo description and photographer's initials.  On rain days that information was entered into a spreadsheet and all of the photos in the photolog were stored in a single folder (backed up in many locations, of course).  These photos are technical photos that show some aspect of the sites, features, or artifacts that we felt were important to record and preserve.

The notes that go in the photo log are invaluable.  Without the notes, would I remember that this pile of rocks is a cache and that this is the view of them facing northwest?  Probably not.

Digging through the photolog
Now I'm going through the photolog and winnowing it down again to find the photos that best illustrate the sites for the final report.  These photos, along with maps, tables and text will be the record of the sites.  For newly discovered sites, they will be useful in relocating the sites in future years and in the case of mitigated sites, they are the final record of how the sites appeared before, during, and after excavation.  Archaeological excavation is a destructive process so its important to keep good records as you work.

Photo Credits: Tim Rast

Sunday, November 13, 2011

Bringing Home Rouffignac Cave Art

Rouffignac Mammoth (copper etching)
On our trip to France, we visited Rouffignac Cave to see the 13,000 year old cave paintings.  This was the first time I'd been in a cave or seen Palaeolithic art with my own eyes.  It was an incredible experience.  We had a few upper palaeolithic sites on our agenda and we thought we might get "caved-out" at some point and want to move on to something else.  I don't think that can happen.  Once you see one cave, you want to see them all.

Me and my Rouffignac Mammoth
The paintings and etchings in Rouffignac are known especially for their depictions of mammoths.  According to the visitor's guide to the cave; of the 254 works in the cave, 157 (or 61.8%) of them are of mammoths.  I was especially interested in seeing them, because I used one of the mammoths from Rouffignac as the model for a tattoo of a mammoth that I have inside my right arm. Its part of a band of cave art that goes around my arm, and includes a wooly rhino from Rouffignac as well.

Copper etching of the Three Rhinoceros Frieze, Rouffignac. Atelier Tara.

Print Shopping in the gift shop
Photos aren't allowed inside the deepest part of the cave, where the paintings are located, but the gift shop and information desk are located inside the mouth of the cave and photos are allowed there.  I don't have any shots of the actual paintings,but you can see some images on the official website.  The depictions of Rouffignac art illustrating this blog are from prints that we purchased in the gift shop.

Glass mammoth skull and tusks by Jean-Paul Raymond

Glass axe, even the lashings are glass
While we were visiting, there was an exhibition of blown glass objects by Jean-Paul Raymond called Fragments de Temps inside the cave.  The glass was worked into horns, wood, bones, and stone objects from the Upper Palaeolithic. Visitors pass Raymond's intricate and accurate reproductions as they walk deeper into the cave.

Glass spear head in foreshaft.  Notice the flint nodules poking through the chalky walls around it.

Everything is hollow glass

The deepest paintings in the cave that are accessible to the public are a kilometre from the entrance, so the tours are done by train.  Much of the trip is in the pitch black darkness of the cave.  The tour guide has a small flashlight and will turn on lamps at specific stops along the way.  The art is either etched into the wall or painted on in black manganese.  Some of the wall surfaces are so soft, that the etchings were done by fingertip, perhaps even by children. We saw the caves with a trainload of kids - perhaps that's the way they were always meant to be visited.

The Ten Mammoth Frieze.  The original painting, inside Rouffignac, is 29 feet long and each mammoth is about 3 feet long.  The colours shown in the copper etching are also seen in the cave.  A band of white calcite has formed over the lower half of the wall, covering and obscuring the legs of the two groups of mammoths, meeting face to face in the middle.  The band of calcite, is one of the clues that helped establish the authenticity of the cave - it obviously formed slowly, over time after the paintings were put on the walls.  Copper Etching from Atelier Tara.

Approaching the train
The cave itself is a long narrow tunnel formed by water action over the past 70 million years.  In parts of the cave the floor has been dug out to accommodate the train tracks, but for the most part the passages are very uniform.  You can see the walls on either side and it feels like you are travelling down a long dark tunnel with chalk and flint walls.  Descending into the cave there are cave bear claw marks on the walls and several hundred metres of bear lairs; hundreds of giant nests scratched and wallowed into the clay floor.  Many of the paintings are located on the far side of these bear lairs.  The painters (and their kids!?) would have had to crawl through these still warm bear beds on their knees and bellies to reach the galleries in the deepest reaches of the caves.

This is a section of the Great Ceiling, located a kilometre deep in the cave.  The painters would have lain on their backs and painted the ceiling above them by lamp light.  (Copper Etching from Atelier Tara)

Cave Art Prints, Rouffignac and Pech Merle
On the way out we stopped in the gift shop and loaded up with books, photos, and craft documenting the cave, including the copper etchings that have illustrated this post.  The four prints came from the Atelier Tara, a workshop in southern France.  Having just gone through the cave, we were impressed by how accurately the prints captured the 13,000 year old artwork and now that they are framed and hanging in our stairwell, it feels like we have a little bit of Rouffignac here with us.

Photo Credits:
1, 3-8, 10-13: Tim Rast
2: Lori White
9: Rouffignac Interpreter (Sorry, I didn't get your name, but you did an awesome job! Thanks.)

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