Pour réaliser cet émail « liège », mon point de départ était mon émail blanc auquel j’ai ajouté du fer dans différentes proportions:
Samples 3 and 4 (red dot) catch my attention, so I keep these iron concentrations.
Tin oxide (part of my white glaze) is a rather expensive raw material. According to the literature, it is possible to use zirconium silicate as a substitute. So I replace the tin oxide by zirconium silicate. I use the 2 concentrations of iron selected above and vary the zirconium silicate in two different concentrations:
At the top, we find the low concentration of iron and at the bottom a slightly higher concentration. The lower tests give a brown color that I think is not very good, so I give up on that. On the other hand, the sample with less iron and more zirconium silicate gives me an interesting mottled glaze. I continue the tests from this sample (with the red dot).
I then proceed to a test on larger pieces to observe the rendering:
Here, I like the result! I decided to do a thickness test before adding it to my collection:
(link to build a small tool to measure the thickness of the enamel) :
Pour aboutir à cet émail « jaune de fer », je voulais en fait obtenir un « bleu de fer » (vous pouvez consulter l’article ici lien bleu de fer). J’ai effectué une recherche en triangle dans le diagramme 25 :
I take the sample 2nd line, first on the left (red dot), to do a search around an iron yellow :
I vary the iron oxide:
Taking the rightmost sample, I perform a search with the cross method:
I then select the sample on the left to perform a test on a larger piece:
Starting from the sample on the left, I try to add silica because the enamel is very runny:
The samples are then less flowing but not really usable, because the enamel is no longer fusible either.
I also test the thickness of the enamel, and it is, finally, this parameter that will solve the problems:
We notice that sample n° 2 does not sink and develops a nice yellow tressaillé.
I then carry out a test on a larger piece with a larger quantity of enamel preparation:
Le résultat obtenu me paraît intéressant, bien qu’il me reste à comprendre pourquoi le bleu et la cristallisation n’apparaissent pas partout ni lors de chaque essai. Je décide, comme pour le « bleu de fer », d’effectuer un nouvel essai avec tamisage et un autre sans tamisage, pour constater si ce paramètre peut avoir un effet :
In view of the result obtained, which can be considered as identical on the three samples, I decide to redo a thickness test:
(link to build a small tool to measure enamel thickness)
The test is more or less conclusive. We notice that the enamel must not be thick, otherwise it's a disaster!
This beautiful water green glaze was discovered by chance! That's the beauty of searching for new glazes! Sometimes you discover things (often not aesthetically pleasing) but you get nice surprises from time to time. You have to try to interpret what you see and do new tests to develop a new glaze.
This one was obtained while researching my lichen green enamel. Indeed, this one seemed to me too runny. In order to make it more viscous, I tried to vary the presence of silica and I obtained this:
The result obtained with the most silica (red dot) gives us a blue green that is unexpected but not less interesting!
I'm trying to apply it to a larger room:
The color appears but in a rather disparate way, probably due to the method of application (brush). Indeed, by applying the enamel with a brush, it is often difficult to obtain an identical thickness on the whole piece. Here the color appears on the areas where the enamel is the thickest.
In order to understand a little better this enamel, we proceed to a thickness test (You have a small description of the manufacture of the tool here ):
We can clearly see that the first 2 layers do not show the green water. Thickness n° 3 is the one to try to reproduce. From 4, the glaze becomes runny.
The water green glaze obtained here consists for a large part of oak ash!
For this glaze that I call oil blue, I started from my oil red glaze. I added cobalt oxide in different proportions:
Very little visible, but a green and bluish color appears on the 2nd and 3rd samples.
I decide to continue my research with the cobalt concentrations of the first 3 samples and by varying this time the iron oxide, top cobalt at 0.1%, middle 0.5% and bottom at 1%, and from left to right from 5 to 9% iron oxide.
Close-up of the three samples at the bottom left:
On the 1% cobalt samples, the green/blue tint appears more clearly but the whole thing remains quite dark. I thought that, by decreasing the concentration of iron oxide, this oil drop aspect would disappear but it is not the case!
I start 2 tests in parallel: a cross method from the sample with 5% iron oxide:
... and I continue to lower the concentration of iron oxide:
The cross method does not bring us much, we notice that the tests remain very dark. On the other hand, the decrease of the iron oxide concentration makes this blue appear even more!
I then decided to test the 2 samples on the left on larger pieces to see the result:
I proceed to another test by lowering (again) the iron ox (sample):
Here, it is no longer what I am looking for, namely the oil drop phenomenon.
I take my formulas above and make a test by playing with the thickness (see here for the explanation of the construction of the tool):
In the middle I find the right thickness to show the stains due to the presence of red iron oxide ( see the article on oil red ). After testing this enamel with this thickness I get:
I specify that this enamel is all the more enigmatic because it is very difficult to take a picture. Indeed, in daylight it always appears much bluer than on the photos, I have tried many settings, point of view, camera ... it is very complicated to find the color of this enamel on the photos.
If we go back to the thickness test, I also find the enamel very interesting when it is applied thick! Unfortunately it is not topped. I could certainly increase my end of firing level but it would also impact my other glazes. That's why I prefer to keep the firing curve the same and work on the glaze composition. I am continuing my research and varying each of the components separately to see what can make the glaze a little less viscous in order to have a topping.
This test is very interesting, we see according to the raw material that we vary the impact of it. Here at the top, we find our control sample. On the second line on the right it is the sample with a little more Nephline Syenite. On the third line on the left, it is the sample with a little less kaolin. These are the 2 samples that appear as good as the control sample.
I decide to test these 2 on larger pieces to see if it's worth going further or if I stay on my control sample.
the test with more Nephline Syenite:
We notice that this test gives very similar results to what I had obtained initially.
The test with less kaolin:
By adding kaolin, we can see that the oil drop phenomenon appears much better. So this is the solution I will choose!
To obtain this lichen green glaze, my starting point was my first research with oak ash, thanks to which I obtained a transparent glaze. I decided to keep this same base and to add metallic copper oxides in different proportions:
We find the obtained tressaillage and we obtain moreover a green color. We can notice however a very runny glaze. To make the enamel less runny, I increase the ash content (top), then I increase the nepheline syenite content (bottom). The result is confusing:
There seems to be no difference between these tests... So I give up on changing the glaze constitution. Using my middle recipe, I try to apply this glaze on a larger piece:
The positive side is that I find the color and the braiding. The negative side is that the glaze is very runny and looks very impacted by the thickness since we can see unglazed areas at the top of the piece. The enameling of this piece was done with a brush, hence the important differences on the piece.
It is important to test the thickness of this enamel (link to build a small tool to measure the thickness of the enamel):
We can observe, as with my transparent tressaillé glaze, a flowing glaze when it is laid thick. The ideal sample is between sample 2 and 3.
As for the transparent version of this glaze, we can further highlight the cracks due to the braiding. For this, we proceed to the addition of Indian ink that will seep into the cracks.
Pour réaliser cet émail « bleu Majorelle » (bleu que l’on trouve partout lorsqu’on visite le fameux jardin de Majorelle à Marrakech), mon point de départ était mon émail blanc auquel j’ai ajouté du cobalt dans différentes proportions:
Sample 4 (red dot) holds my interest, I keep this cobalt concentration and I vary the tin oxide used, in principle, to mattify the enamel:
The impact of the tin on this glaze is clearly visible. The glaze becomes more viscous (less flowing) when tin is added.
Tin oxide is a rather expensive raw material. According to the literature, it is possible to use zirconium silicate as a substitute. I replace the tin oxide with zirconium silicate and vary the proportions in order to compare the matting power of each oxide:
Indeed, after comparing the results, zirconium silicate brings a similar effect to tin oxide. So I choose this option. I select the second to last sample (red dot) and test it on slightly larger pieces:
I'm happy with the result! This enamel joins my collection!
In order to obtain this transparent glaze with braiding, I started a research around oak ash, mixing, in equal proportions, oak ash and Nepheline Syenite, while adding silica in different proportions:
The sample on the bottom left contains the least amount of silica. I decide to continue to lower this rate and then, when it is zero (top right sample), I proceed to an addition of alumina through kaolin to observe the reaction:
I select the sample (top left) where we can see a beautiful crackling (crackling of the enamel due to a difference in expansion between the enamel and the shard).
This enamel seems satisfactory, I decide to try this enamel on a more important piece:
I then get a nice tressaillage. I will continue my research by adding metallic oxides to this glaze which you can follow in other articles. I will also do a thickness test (see here for the explanation of the tool construction): with this transparent enamel:
We can see that the glaze is very runny if placed thick. The second sample corresponds to the thickness that we will try to reproduce. This is to obtain a nice braid without too much flow.
And one last little trick to bring out the tremor on the piece: we add Indian ink to the brush on the piece. The ink will seep into the cracks. Once the ink is dry, simply clean the ink from the surface of the enamel. And you get a great effect. I have done the operation on the back of the sample 2 above:
Here are some examples of achievements with this enamel:
ref 60028 & 50028ref 70 007ref 40 016
Pour cet émail que je nomme « peau de crocodile », mon point de départ était mon émail rouge d’huile, auquel j’ai ajouté de l’oxyde de cobalt en différentes proportions. Voici le résultat:
It is very little visible, but a green and bluish color appears on the 2nd and 3rd samples.
I decide to continue the research with the cobalt concentrations of the first 3 samples and by varying this time the iron oxide, top cobalt at 0.1%, middle 0.5% and bottom at 1%, and from left to right from 5 to 9% iron oxide.
The middle line shows a drop of oil with an orange/brown tint on a green background. I find the effect interesting.
I select the leftmost sample on the middle row and decide to test it on a small piece:
As the result was very disappointing in my opinion, I was about to throw in the towel with this enamel. Instead of throwing away the excess enamel, I decided to apply it on a piece to finish it. Unfortunately, or rather fortunately, I had a little more left over than I expected. I had to apply it quite thickly to finish it.
And here is the result!
I tell myself that, in the end, it's still worth it!
So I decided to test it with different thicknesses:
On s’aperçoit encore une fois l’importance de l’épaisseur de l’émail (lien pour construire un petit outil pour mesurer l’épaisseur de l’émail) avec cet émail « peau de crocodile »!
J’ai nommé cet émail nuit étoilée. Je souhaitais obtenir un émail « kaki » en utilisant comme point de départ le diagramme 48 de Daniel de Montmollin, avec un taux d’oxyde de fer de 25%. Je fais une petite série à l’aide d’un triangle:
The point A0 (close-up) that I select to continue my research:
I add bone ash at different concentrations:
... and I get, for the highest concentration, on a particular area of the test, a rather intense glittery red that intrigues me!
I then choose to think further and do a search with the cross method:
I find my intense red glitter and some details that make me think of crystallization! It turns out that the result is quite different from the previous result. This should not be the case. It is only when I go back to my tests several months later that I discover my mistake. The concentration of iron oxides is 2.5 times lower between the sample in the close-up and the one in the middle of the picture above.
I decided to test the top sample on a larger piece:
This glaze is very interesting; I decide to make a larger quantity. Once prepared, I test it on a larger piece:
The result is just as interesting although different, probably due to the thickness of the enamel. This test made me think of a starry night, hence the name of the enamel.
The importance of the enamel thickness can be seen. On the left, we obtain a brown color without much interest. In position 2, the thickness is ideal to see the nucleations appear and, from the 3rd sample, the enamel flows. It will be necessary to be careful when applying this glaze. I lost a big bonsai pot by using it too early (before this thickness test), failure due to big drips.
To make this metallic eggplant glaze, along with my oil drop research, I make a triangle with a higher iron concentration than my oil drop glaze in diagram 48. I make a small series using a triangle:
I retain sample B0 (2nd from the bottom left):
Then I perform a search with the cross method, varying SiO2 and Al2O3:
I then get, in the center of the cross, a metallic purple black that is close to the color of eggplant:
