Archive for March, 2016

  • Photos

    Smartphone Microscopy

    Last year I purchased a USB microscope (see article).  It’s pretty fun, but ultimately I was really disappointed by the quality of the images.  The 5MP sensor seems pretty cheap and images have a lot of artifacts.  Furthermore I was never satisfied with the color.

    The best choice would probably be a “real” microscope with a camera adapter.  However, this little hobby of mine doesn’t justify spending a lot of cash.

    There are a few tutorials online for creating your own phone microscope using the lens of a laser pointer.  (I tried this and it worked pretty well, but I never found a way to conveniently attach the lens to the camera.)  Wired’s article Turn Your Cellphone Into a High-Powered Scientific Microscope has a good tutorial as well as background on the scientists who are using cellphones as biomedical devices.

    Fortunately there are now multiple products for sale that make it easier to attach a lens to the phone.

    There’s a former Kickstarter project that looks promising and is shipping, the 15x Micro Phone Lens and 150x Micro Phone Lens. (See my November 2016 update, below.)  In China there are a number of cheap alternatives.

     

    Supereyes Smartphone Microscope (Not recommended)

    I purchased the Supereyes Smartphone Microscope for about $7USD.  The images below were taken with this lens.  Unfortunately the top of the plastic lens is not protected and I scratched it after playing with it for less than an hour.

    The images from the iPhone with attached lens look much better than my USB microscope.  The photos below were taken in natural light.

    The lens attached to the iPhone. On top is a plastic cover which is easily scratched. I removed it with a Dremel.

    View of ruler through attached iPhone lens

    After zooming in with fingers (digital zoom)

    Qing Dynasty Guan glaze

    Qing Dynasty Guan glaze

    A Wanli dish shard

    Blue & White birds in the Wanli shard

    Teadust Glaze

    Iron Red (Kaki) Glaze

    A celadon glaze I'm working on

    Eyeskey 12x Micro Lens

    It was only after using the Supereyes lens that I realized it’s horrible design (does not fit on camera lens, slides off the camera lens, plastic cover easily scratched, etc.) that I bought another cheap microscope lens, the Eyeskey 12x Micro Lens (also about $7USD).

    The Eyeskey model is designed much better.  An adapter slides perfectly over the phone and the lens is screwed into the adapter.  The plastic tube that is visible using the Supereyes lens is not a problem here.  The magnification is also greater than the Supereyes lens.

    (Unfortunately I could not find this model for sale in the West.  However, I think the 15x Micro Phone Lens might be even better.)

    The Eyeskey lens with phone adapter. Much better design than the Supereyes.

    Viewed using the Eyeskey lens. Notice that there is no circular tube visible.

    Zooming in with fingers (digital zoom). Magnification is higher than the Supereyes model.

    Another Iron Red glaze

    Strange rivulets and eyes in a Tenmoku glaze containing Rice Straw Ash

    A Jun celadon glaze on black stoneware

    Porcelain stone and wood ash with carbon trapping and iron spots

    Coleman Kaki on porcelain, cone 9

    Comparison of Supereyes and Eyeskey Lenses

    Supereyes lens

    Eyeskey lens

    Supereyes lens digital zoom

    Eyeskey lens digital zoom

    Microphonelens 8x Macro & 15x Micro Lens

    On a recent trip to the US I ordered the Microphonelens 8x Macro lens and 15x Micro lens.  These lenses are different than others- they simply stick to the phone’s camera lens and have no outer support column.

    In use, I found it more difficult than the other lenses because I could not directly rest the lens at the correct distance against the viewed object, resulting in more blurry photos due to camera shake.  Also, while the micro lens is designed to stick on the phone lens it falls off if touched and gets dirty in the process of handling.

    These drawbacks are forgivable, though, as the quality of the images seems superior to either of the other lenses I tested.  Also, the lens cleans up easily with just a bit of pure or soapy water.  The soft material also scratches less easily than hard plastic lenses.

    For viewing glazes, both the 8x and 15x lenses are useful.  I would recommend the 15x (although of course it has a narrower depth of field).

    The microphonelens case with lenses

    The 15x microphonelens lens on an iPhone

    8x microphonelens macro lens

    8x microphonelens macro lens

    15x microphonelens micro lens

    15x microphonelens micro lens

    Blurred image, lens just needs cleaning in a bit of water.

    Stitching photos

    I tried the iPhone’s panorama feature but it did not work.  The iPhone panorama gets confused.  However, you can take multiple photos (moving the camera slightly each shot) and then stitch the photos together using software.  Adobe Lightroom (Photo Merge->Panorama) and Photoshop (Automate->Photomerge) have this feature , however it takes a lot of time and seems limited to 100 or so photos.  I tried a free program called AutoStitch that worked pretty well.

     

    AutoStitch image stitch of Iron Red (Kaki) glaze. Autostitch options: Multiband->Blending Bands = 2 (default). You can see a lot of ghosting where images weren't aligned properly. Photos from Supereyes lens.

    AutoStitch image stitch of Iron Red (Kaki) glaze. Autostitch options: Multiband->Blending Bands = 10 (needed over an hour to process 78 photos). Photos from Eyeskey lens.

    AutoStitch image stitch of crazy Tenmoku iron glaze by Kimura Moriyasu. Photos from Eyeskey lens.

    Photoshop photo merge of Song dynasty saggar with natural wood ashes. Photos from Eyeskey lens. Photoshop seems to do a better job than AutoStitch (in default mode).

  • Family

    Yangchow Internment Camp

    These are some of my great-aunt’s photos of Yangchow camp.

    She notes the duration of internment as starting on 13 March 1943 and lasting until 6 October 1945.  She was housed in Yangchow Camp “C”.

    An interesting history of the camp can be found on Frank Waller’s website at http://www.haikufrank.co.uk/memories_of_yangchow.html

    Some of these photos and more can be found on the Australian War Memorial website.

    If you have information regarding these photos or would like high-resolution versions, please contact me.

    As captioned by Frank Waller, House no. 2 (Government house) and house no. 3

    Hospital, House #1, Camp C

    House #2, Camp C

    Possibly House #3, Camp C

    As captioned by Frank Waller, House #4, reserved for families.

    Internees at Yangchow Internment Camp

    The Belgian Group

    The Hospital

    The Wash House

    The Bakery

    The Goatery

    The Hospital & Kitchen

    Captioned End of War in my great-aunt's photo album. Relief supplies parachuted into Yangchow camp at the end of World War II. In the background is Yangchow's city wall. Frank Waller's article suggests these drops began around mid-September of 1945.

    Main Gate of the Yangchow Camp. Possibly after VJ Day.

    Sometime after VJ Day, the raising of the Allied flags over Yangchow Camp.

    A gathering of the internees, possibly after VJ Day.

  • Glazes

    Spraying Glaze

    Spraying glaze is a fairly complicated process.  There are craftspeople in Jingdezhen whose only job is going from workshop to workshop spraying glaze.  There are so many factors involved with spraying (the type of work, thickness of work, type of glaze, glaze consistency, air pressure, spray head type, even weather) that it requires years of experience to be able to master the art.

    I hope to slowly add to this article in the future.  For now I will just lay out the basics of how I spray glaze.

    The Spraying Booth

    My spray booth is made locally in Jingdezhen.  It’s a simple stainless steel frame with glass.  A large fan is attached to the back, sucking out particles.  Water is pumped from a bucket through a hose that leads to the top of the booth interior.  The water is channelled along the top of the glass and then exits through small holes, forcing the water to run down the glass, washing away glaze.  The water finally exits through a hole in the bottom of the spray booth, pouring back into the water bucket.

    A typical Jingdezhen spray booth

    A gap between glass and stainless steel reservoir evenly distributes water down the glass.

    The fan at the back of the spray booth blows out particles.

    Detail of the fan label

    The pump sucks water from a bucket and up through the spray booth.

    Detail of the water pump

    Inside the booth I place a large plastic basin for collecting glaze. Inside the basin is a turntable.

    On top of the turntable I place a plaster disk. The added weight results in more even turning, while the plaster absorbs glaze. A notch in the plaster helps with counting revolutions. After spraying, glaze can be scraped off and collected.

    The Air Compressor

    I have an old, noisy air-tank compressor that I rarely use.  I much prefer the Jingdezhen method- a cheap magnetic air compressor used in fish tanks.  I’ve used my current compressor for six years and it still runs great, with no need to worry about adding oil or filtering the outgoing air.

    I’ve found that a 520W compressor is ideal.  In the past I had a smaller compressor that didn’t spray as well.

    The sprayer does a great job of mimicking traditional Jingdezhen glaze spraying using just the breath.  A normal air compressor using a paint sprayer head will give you a finely atomized cloud of glaze resulting in a powdery glaze application.  But a traditional mouth sprayer connected to the fish tank compressor will give you relatively large glaze droplets that soak into the clay, leaving a more compact glaze application.

    The fish tank compressor method also sprays less glaze into the air.  I often just run the water pump and leave the booth fan off (but of course I wear a good respirator).

    Note that this type of spraying results in more water being absorbed into the ware.  Especially for thin pieces, care needs to be taken not to overload the ware with water.  I usually spray the outsides one day and the insides the next, giving the ware sufficient drying time in-between sprays.

    If while spraying you notice the glaze stays wet and shiny on the surface it means you are either spraying too close or have already reached saturation.  This is bad.  There’s a good chance that the entire glaze layer will separate from the ware.

    My air compressor is actually just a cheap fish tank pump. It's much quieter than normal air-tank compressors.

    Detail of the 520W fish tank magnetic air pump, rated at 0.04MPa (approx 6PSI)

    The spray canister is attached via rubber hose. A shut-off valve to controls air flow.

    Mouth sprayers

    The glaze sprayers widely used in Jingdezhen were originally meant to be sprayed using only one’s mouth.  Since then, the mouth stem has been modified from conical (larger end towards mouth) to tapered at both ends for a tight fit into an air compressor hose.

    Making these sprayers is a specialized craft.  The sprayers come in dozens of different configurations.  The sizes of the container, nozzle, and mouth stem as well as the distances between these parts, all determine the characteristics of the spray pattern.  In general, larger containers are used for larger work (e.g. sculpture), while the smallest containers are used for spraying underglazes and details.

    The parts that make up a glaze canister.

    Some of my locally made glaze spraying canisters

    Comparing spray patterns. On the left, Paasche L Sprayer #4 attached to air-tank compressor, approximately 30-40 psi. On the right, Jingdezhen glaze canister with fish-tank magnetic air compressor.

    The Paasche L Sprayer #4

    The Paasche L Sprayer #4

    Like Jingdezhen glaze canisters, the Paasche allows you to make fine adjustments in distance between the nozzle and container tube.  Along with adjusting air pressure and glaze thickness, a number of different spray patterns can be achieved.

    Spraying

    It’s difficult to write about actually spraying glaze, because each session is different.  The basic process is:

    • Spray outsides.  Do not rest ware directly on turntable or plaster disc, but rather elevate it with a stable item such as a smaller plaster column.  If the inside is already glazed, on top of the support you can add a sponge disk.
    • After spraying the bottom, you can scrape glaze off of the feet.
    • Ideally, wait one day while the bottoms dry completely.  If in a rush, blow air over the ware with a fan.
    • Spray insides.  Take care that feet are not resting on a surface that will become wet during glazing.  The dry plaster turntable disk helps with this issue.
    • Clean glaze off the feet by trimming or with a sponge.

    To spray:

    • Using a notch in the turntable disk as a guide, keep a mental note of how many revolutions you make and the resulting thickness of the glaze (checked by scraping).  The number of revolutions will vary each glaze session, and is influenced by the glaze canister, air pressure, glaze consistency, size of ware, etc.
    • Keep the glaze canister in constant, steady motion- up & down, side to side, or circular.  You may need to vary the motion to get consistent application.

    Using a toilet brush for mixing up the glaze each time I fill the canister

    It's difficult to see in this photo, but the center of this dish was trimmed thin, and the sprayed glaze has saturated the ware. The surface of the glaze is no longer powdery. Stop spraying.

    I've found no consistent way to check glaze depth other than scraping with a knife.

    After spraying the bottom, glaze can be scraped off with a box cutter blade or metal rib. Take care not to scratch the ware.

    After spraying the bottom, a board is placed on the foot, then flipped over and placed on a ware board.

    A large circular piece of foam is used to flip over glazed ware, protecting the insides.

    Ware is placed on a damp, firm foam pad and rotated using even pressure, resulting in a clean glaze line.

    Foam after cleaning a bottom. Foam firmness and hand pressure determines glaze line height.

    Another method for creating a clean glaze line- using a notched rib.