Sunday, September 4, 2011

Purple Patch! Rule Breaking!

Having previously discovered the dramatic effects of a reduction atmosphere on crystalline glazes containing titanium dioxide, I made a little kiln load of pots, glaze fired them, and then put them through another firing where I introduced cooking oil into the electric kiln at one drip per second as the kiln cooled from 800 to 620 Celsius (1472 - 1148 F).  The results were most interesting, especially so if you saw the pots before and after the reduction firing.  Let's do just that!

Here's a pot that has 6 percent titanium oxide in the glaze, giving white crystals on a white background.  The pot has its stand and glaze catching saucer still attached, all that has to be separated from the pot after the firing, and any runs and sharp bits of glaze that are still attached to the pot have to be carefully ground off.
Here is the same pot after the oil drip reduction firing, with white and green crystals on a purple background... amazing really!

Here is a friend for the pot above, same glaze.  In this one the glaze was a little thicker and the white was more "white" looking!  The puddles of glaze in the saucer show just how much glaze runs off these pots whilst they are at high temperature in the firing.  The glaze has to be runny when it is hot for the big crystals to grow.
More of the green, white, and purple... what fun!
This pot had a little change in the glaze recipe, notice the ivory colour, the "softer" looking crystals, and the strange greenish colour run off glaze in the catching saucer.  I replaced the titanium with rutile, which is a mineral that is rich in titanium, but is not as refined.  As is the case with people, some of the nicest people are not all that "refined" either, and the ups and downs that they have experienced in life add character.  With rutile there are traces of iron and other impurities that can make it a very useful glaze ingredient. 
You may notice a more ivory colour to the crystal margins, and the purple colour is deeper.  Rutile also has a greater fluxing effect, and the crystals tend to grow faster than in a base with Titanium dioxide.  For a more "perfect" outcome I would need to fire the two glazes separately, so as to enable me to juggle the temperatures for the optimal time for each glaze.  Ideally I would prefer there to be more of the purple on this pot and the crystals to be a little smaller.  I could also try to "tweak" the recipe to make it more compatible with the titanium variation.
Here is another pot from the firing, also with the rutile glaze variation.
Rules and Breaking Them!
The whole thing of what is "right" or "wrong" in the look of a crystalline glaze intrigues me.  After all, I am sure that the first crystalline glazes occurred as a frustrating glaze fault rather than as something intended, and yet it has not taken people long to make rules!  Some crystalline glazers would label a crystalline glaze, where most of the crystals touched, as being "over nucleated", and they might aim for between 3 and 5 large and spectacular crystals on their pots.  Others are happier with an even coverage of much smaller crystal formations.

I do think that there is still a great deal to be explored with crystalline glazes.  Crystalline glazes are runny by nature, and want to form waterfalls down the side of the pot when at high temperature!  Could this be used expressively instead of caught in a catcher and ground off?

Playing with glaze runs!
The texture of touching crystals is rather like lichen or a bacterial growth; again, could this be used expressively?

Crystals as texture.
Crystalline glazes are often shiny, but they can also be matt (UK English) or matte (American English)!  There are expressive possibilities here.

This little crystalline pot has a matt surface.
My feeling is.... that it is important to make things that obey the "rules", this can help with learning the craft and to master technique.  And.... it is equally important to also make things that deliberately break the rules!  Breaking the rules is all part of learning who we are. It is a bit like being a teenager!

Crystalline glaze with wood fired reduction and carbon trapping.
Several years ago, when I was teaching painting to groups of adults, I was often intrigued to observe how conservative amateur painters could be (and I am sure this is also true of photographers, writers, and musicians as well!).  It always seemed remarkable to me that people who did not have to depend on selling paintings in order to make their livelihood, and did not even have to exhibit them, were often the most reluctant of all people to take risks, to try new techniques, or to paint something that might challenge them!  It was like offering a child the whole contents of a lolly shop, and have the child refuse the "good stuff" and just select a single piece of plain chewing gum!  (If that image is offensive, due to its un-healthiness... and, it does occur to me that it might be, let's say that it is like taking a vegetarian into a marvellous vegetarian restaurant and them ordering tofu with nothing else to go with it!)

Fear is the enemy here.  The variety of fear that leads to rule making, the following of strange doctrines, intolerance, selfishness, and, ultimately, to ignorance!

Not sure why I went away on that tangent, put it down to too much coffee!  I have been firing a crystalline glaze firing overnight and made an early start today to watch temperatures as the kiln came up towards the peak of the firing.  It is nearing the middle of the day now and I will be able to shut off the kiln soon.  This load is mostly crystalline bowls.  I usually have a high failure rate with crystalline bowls (getting the glaze the right thickness is very important), and I need to do a lot of tests and firings in order to improve that.  If it was too easy, it would not be so fascinating!


Linda Starr said...

I absolutely love that first purple pot, how wonderful, and you know purple is supposedly the color of royalty. Great work Peter.

Peter said...

How lovely to hear from you Linda,
I always assume your half of the world to be fast asleep when I am doing a new post, I never do quite visualize the time zone thing all that well! If purple is the colour of royalty, I'll have to remember to be on my best behaviour when working on a purple pot!

Linda Starr said...

Hi Peter, it's only 9:30 pm here in Florida, not so late, but in my old(er) age I seem to be keeping different, more erratic hours than I used to. Ha.

gz said...

"rules" in this matter are guidance.
In art there is no "right and correct" way to do things, there are so many variables before you add in a person, let alone after

cookingwithgas said...

rules are for breaking!
Break away and don't listen to all the Blah-Blah-Blah!
Love the purple-lovely!

Judy Shreve said...

I love the purple - what a difficult color to achieve & yours are brilliant!

I wonder why some of us are risk takers and some of us are not -- I actually think if we could keep art an important part of education - we would learn to take risks in a 'safe' environment. Art offers challenges and requires (and teaches) critical thinking. Now you got me ranting lol.

Your work is just stunning and thanks for showing before & after photos.

Hannah said...

Blimey that purple is very exciting.Yes rules are guides in this sense as suggested above. great discover with the oil, do be careful though.

Angie said...

Love the effect from the oil reduction..deserves a 'WOW' for rules ...I do agree, one has to follow the rules when learning ...but is the breaking of rules that results in discovery ... and invention .xx

Peter said...

Hello Gwynneth, Meredith, Judy, Hannah, and Angie, Lovely to hear from you all. Sounds to me like there is a consensus regarding rules, the breaking of them, and the educational value of that! People who have artistic leanings would seem to be revolutionaries at heart!!

Thinking of Judy's comment, maybe it is a good thing that some take risks and some try not to, I guess it keeps things moving ahead, but with sane checks and balances. The "variable's" (that Gwynneth alludes to) of people are actually rather important!

I do think that a really great education system could be built around art. In my case, I have developed so much greater interest in the sciences, geography, and engineering since starting to play with clay.... I've even been known to get a bit philosophical!!

Rest assured Hannah, I still have both eyebrows in spite of my adventures with hot kilns and cooking oil (but I am very careful)!

Regarding purple, thanks for your "WOW"s and kind words. I'm finding the purple fairly easy to do, but getting a reliable copper red is much more difficult, so I'll really be dancing when that happens! A little too much reduction gives spectacular copper metal..., but not red, it is a question of just enough and no more! Good fun trying though!

gz said...

Geoff Swindell does much refiring, also sandblasting to reveal the different layers within glazes

acte gratuit said...

I wish you could come set up shop in San Diego so I could learn to do some of this stuff!!!
Beautiful pots as usual!!!

Peter said...

Hi Gwynneth,
Sandblasting has been interesting me a bit. I could imagine something could be done with the pots that I do the oil drip reduction with, as the reduced layer is just on the surface. Abrading it would reveal the oxidized colour underneath.

Hi Emily (acte gratuit),
Lovely to hear from you. Setting up shop in San Diego would make a fairly dramatic change for us, but I could just about be persuaded (especially today as another cold southerly comes up from Antarctica and reminds us that winter was not so very long ago!). If you ever want to ask questions about glazes and so on, please do... I know it is not the same as being just down the road, but I'm happy to help if I can.