Greetings from Philadelphia

[Heidi Maiers]

Ah, no wonder it looked so full and wonderful. Well, it still looks great after firing while there is a noticeable hardness now. The only way to retain that fullness is to cast a water based clay piece and take the mold while the clay is still wet (leather hard).

Children are the most difficult - their features are all hidden beneath layers of baby fat with only a few indications of bony structure. You have nailed it though no doubt due to years of keen observation in your painting practices.

About clays - just because it is a cone 6 or 10 clay doesn't mean you have to fire it to that temperature. I use cone 5 or 10 clays and rarely ever go over cone 02. I usually fire them nearly solid to cone 06 so you are right on. That is plenty hot for vitrification and the piece will only shrink about 5%. Also, any patina that you apply to a piece that has not been fired to maturity will adhere much better.

I love the lighting of your original photograph. What are you using for a backdrop? I know I need to find a good photography background as I have been using sheets and then smudging out any wrinkles in Photoshop that are noticeable in the final photos (can you say big waste of time there?) The grayscale is also very effective in showing off the forms.

You'll have to let me know how you like the Nikon D70. I've been wanting to buy a nice digital camera for quite some time now to upgrade from my old 2 megapixel. I was thinking about the new Nikon Coolpix 8700 would probably be plenty of camera for my needs. I can see where a painter would need to be more concerned about color quality.

Anyway, you came to the right place for boat loads of good information and you obviously have a lot to contribute yourself. Hope to see lots of your work here.

[Garth Herrick]

Thanks, Heidi:

Looking at clay samples fired at various cones, I asked for cone 4 and got cone 6+++++. The kiln was computer controlled, like just set it and forget it. I think the computer was wrong. The piece came out way more golden yellow than any of the pinkish-beige samples, and as I posted earlier, the square base actually became partly glass at the bottom. Ouch!

I think making a mold and casting is the right approach. At least there's the opportunity to do it again, not to mention perhaps a small edition.

As for lighting the photo, for the background, I used a *2-ply archival matteboard off of a roll, which is really the equivalent of a very heavy sheet of drawing paper, about 40" square. For the light, I have a Lowel Tota-Lite on top an 8 foot light stand, with a 30" white photo umbrella attached in front of the Tota-Lite. This made for extremely soft lighting that complimented the the softly rendered features of the sculpture modelling.

I don't have the new Nikon D70, but rather the Nikon D100, it's pricier predecessor. It has been an all round worthwhile camera. I think the D70 should be a good candidate for a new digital camera. Especially for those who like using a conventional SLR.

Heidi, do what I suggested for Marvin on page 2 of this thread, to compare cameras on display in a store. Good luck!

Garth

[Celeste McCall]

Dear Garth,

Welcome, and your work is absolutely wonderful. This is absolutely unbelievable work! Just fantastic. I don't have enough words to describe how impressed that I am with it.

[Heidi Maiers]

It definitely sounds like it got too hot. Did you invest in a computerized kiln, or did you have someone else fire it that has one of those?

A full size computerized kiln is another item on my long wish list, but now I wonder how reliable they are. My old pyrometric cone style one has never let me down and is still going strong after 16 years. Its size is a restriction though (18") which is why I want to go bigger.

Thanks much for the lighting tips - I'll give that a try.

[Garth Herrick]

Thanks, Celeste and Heidi:

Dear Celeste, Thankyou, I feel the same about your work. Actually I feel at a loss of words to express how high in caliber so much of the works are by forum artists.

Heidi,

I don't have a kiln. This piece was fired by the retail ceramic supply store where I had bought all my clay and tools. They have two kilns running on a reservation schedule for customers. I opted for the whole kiln, and not just a shelf, for peace of mind.

When the technician notified me that the firing was done, he exclaimed about the beautiful bright golden yellow color he has never seen from this clay before. I immediately knew something was wrong. I have long wondered if the technician wrongfully set the computer for cone 11, and the covered his tracks by resetting it later to cone 6. We had a written contract for cone 4 which he denied, saying I last said 6. Anyway it looks like the firing went way beyond 6. The computer had on record a maximum temperature reading that was definitly within the upper limit of cone 6. So would this be a human blunder and cover-up, or a computer sensor failure?

Garth

[Heidi Maiers]

Garth,
Hard to say if it was human or mechanical error. If it is a cone 6 clay, it should never have gone beyond its maximum temperature of 2232 degrees (F) or it will literally melt to glass. If it is a cone 10 clay that was fired at that temp, it should still be OK. If a cone 10 clay is fired at cone 11, that will cause the same problems. The cone number signifies the absolute maximum temperature that is reached, not a degree more, and the kiln should automatically shut off at that point to keep the temperature from raising any more.

Was the base actually glass - like, or could it be that the piece was set on a dirty shelf that had residue of melted glazes off of other fired pieces and only the very bottom was glassy?
What did you use to smoothe your surface? If it was just a sponge and water, that wouldn't change the color - but any other substance might.

[Garth Herrick]

Heidi,

There was about a one inch radius semi-circular glass surface on the front face of the square base rising from the bottom center. It had almost a bottle gray green color. 2232F is the temperature, that was registred, and all at the store agreed this clay body should have been perfectly stable at cone 6

To smoothe the surfaces, I tried not to overuse water, because it would subtly erode the surface and expose too much grog, for my liking. I did a lot of tooling with wooden tools and used my fingers a lot. I suppose the natural oils in my skin had some effect. There was quite a motttled range of surface color, which I did not mind. I just did not expect the overall yellow cast that had no relationship with the store samples. Also my sculpture was far less porous and absorbent of water than the cone 6 sample, which also suggests a temperature discrepancy.

I asked the clay manufacturer how a specified shrinkage rate of 12 1/2 % could become a documented 18% in my case. They offered no clue, saying they never test their clays beyond their design limits, and did not want to jeopardize their relationship with the store that serviced me. The store sent them a sample from my firing for scientific analysis, but there was never any findings response.

Thanks for your input, Heidi!

Garth

[Heidi Maiers]

That is strange indeed. What I would want to find out then, is if the clay that you used was actually the clay that you thought you were using. As in a packaging error at the factory and the wrong clay was put in the box you bought. If it was actually a cone 5 clay, that would explain 2232 being too hot for it and also the fact that the color outcome was not even in the range listed for that clay - not to mention the excessive shrinkage, and the too high density. If you bought a 50 pound box, the two bags may or may not be the same, but to be safe, like you say, the next one I would definitely have fired in the 06 range. I have fired as low as cone 018 with great results on a cone 10 clay.

I agree with you about the grog issue - it is easy to overwork the surface with water and bring out too much grog. This is something I've been trying to work on myself since I use a high grog content clay so I can fire them without having to hollow them out.

At any rate, I'm sure you've learned a lot with your first ceramic piece and the next one will be much less frustrating and even more beautiful - if that is even possible.

[Garth Herrick]

Heidi,

I forgot my own method of smoothing. Now I remember: I made a grog free slip from some of the clay and carefully painted it on layer by layer with my best sable oil painting brushes. This I tooled and rubbed with some water until some grog began to surface. Then I would let it set up and dry more and repeat the process until it all looked sufficiently cohesive. I spent a lot of time doing this. The more I refined, the more I found that needed further refinement.

I'm a painter, so naturally I found a painting approach to sculpting. I used all types of paint brushes and found brushing around the clay to be very effective for rapidly cleaning up rough modelling. This was especially true for the ears, nose, and mouth, etc. The ears just appeared like magic, just as if I were modelling paint on a canvas portrait.

Finally the deadline came up, and I had to keep it in a toasty warm place to fully dry for several days. It was at that time when the brown clay fully dried to a light gray, that I took all the photographs. It was fired the next day.

Garth

[Heidi Maiers]

Garth,
That's a very innovative and logical approach - one I would almost expect from such a refined painter. While refinement can become an addiction with sculpture, your piece does not look overworked at all - in fact, your method of adding slip definitely helps the skin look more lifelike and fleshy. I would almost worry about the slip sealing the "pores" where the gases escape through the grog. When you say there was some cracking, was this limited to just the surface, or did the cracks run deeper? I am assuming the cracking occured during the firing and not before while it was drying. There doesn't appear to be any blistering between the slip and the main body, so you did a great job addressing the cohesion issue.

About that strange variegated yellow color - could it be that the brushes you used to mix and apply your slip still contained a touch of paint pigment? If so, that would explain it.