Jump to content
Sign in to follow this  
Gabby

Underglaze color

Recommended Posts

I know most people here mix their own glazes and underglazes, but I hope someone can give me advice on how to mix a color I don't see out of commercially available underglaze  colors.

I do not need precision- just approximation.

There is a sort of auburn color, ubiquitous in the animal kingdom. An orangutan is this color, a red panda,  the red river hog, various setter dogs and other "red" dogs, fox...

I want that color when I fire at cone 5 with clear over it.

Thank you for your help.

 

Share this post


Link to post
Share on other sites

When you say "Mixing" do you mean from the raw materials?  I haven't heard of many potters, that make their own underglaze, because they are a bit of a hassle, compared to making your own glaze.

Now, if you mean "Mixing" by taking two already made, commercial underglazes, and mix them like paint to make a new color, that is easy enough to do.  For an auburn color, I would start with a red orange (Or just orange, then add some red as a pre-mixed red orange, might now be available).  Then add brown in small increments until you reach your desired color.  Keep in mind, the underglaze will change slightly, in the kiln, and will be more vibrant with a clear over top.

Share this post


Link to post
Share on other sites

Nice colours!

...idk, but had fun lookin' at pics of the critters you mentioned.

Aardvark's srf clay is close to that.

The local JC's cone 5 red glaze is close as well (let me know if you'd like pics and/or recipe).

Speedball orange underglaze in reduction is close...

 

 

reds.jpg

Edited by Hulk
crop pic

Share this post


Link to post
Share on other sites

Thank you, Benzine and Hulk.

Benzine, I meant just what you wrote, how to mix together commercial underglazes. I tried this using Amaco underglazes, starting with their terracotta and thought I had it for a sculpture of my deceased English Bulldog.  It looked good in the bisque fire, and then coming out of cone 5 it was more like molasses brown. a real disappointment.

Hulk, thanks for putting up the photos. I hesitate to put up photos, because I don't know how to resize things and the couple of times I have put up photos, they have been huge.

Yes it is a beautiful color. The reason it is so common in the wild is that the way the tropical sun gives color to the moss and leaves on trees makes the foliage in their habitats look this color, or like a combination of this color and dark green. As striking as these animals are, so that when we look at them we ask, "How could that color provide good camouflage?" these animals, even the bulky orangutan, are invisible up in the canopy, the red panda in crooks of trees, and the red fox on the forest floor.

Share this post


Link to post
Share on other sites

A triaxial or line blend study of different commercial produced underglazes might lead you to your desired results faster than mixing your own from raw materials. John britt has a great video snippet online doing a triaxial blend if youve never done or heard of one. Line blend is basically two colors in gradated portions mixed together; 90/10, 80/20, 70/30....you can get more specific or more broad with your ratios (on a 5% increase, 10% increase, 20% increase). A triaxial blend is the same idea, just three colors instead of one.

Do some tests, and fire them to your desired temps. Make your test tile from a slab, and mark off the portions with an underglaze pencil so you can have a "grayscale/colorscale" to look at when you are surfacing. A hole in the corner is wonderfully helpful to hang it out of the way when not in use.

Share this post


Link to post
Share on other sites

The clear glaze chemistry can play into how the colour of the underglaze turns out. If you look at the reference chart that Mason supplies you can see that all the orangey/browns have the same reference notes, temperature wise you are fine at cone 5, but it also says can be used with/without a glaze containing zinc but it does better with a zinc glaze. Calcium can change the colour of iron also, all of Mason's browns contain iron. I would assume that the stains used in the underglaze will more than likely use the same structure of stains.

Re mixing underglazes/stains, sometimes this works but if the crystal structure the stain is based on is not the same one with both stains used in the underglaze then the blended colours might not be as predictable as blending 2 or more stains/underglazes that have the same crystal structure.  

Share this post


Link to post
Share on other sites

I would just do some tests.  Mix up a couple different potential colors, keeping track of how much of each you used.  Fire them, both with and without clear glaze, and see which one works the best.

Documentation will be key.  Nothing would be worse than finding a color that is perfect, only to not know, how exactly you made it.

Share this post


Link to post
Share on other sites

gabby,  if you are using a white clay, try adding a little red iron oxide to your throwing slurry and painting it on the form.  start as suggested with a little and add some more RIO until you get to the color you want.  if you use a different color clay, maybe that will work as well.  if it has a lot of grog, screen it out to make it paint more easily.

Share this post


Link to post
Share on other sites


Long ago I in my color class, the assignment was to create a grid of our required paints, which were white, black, cobalt blue, a red, and a yellow.   the rows and columns were for the pure paints. 
first grid was for a ratio of 1/9 of the column to the row. 
the second grid was for a ratio 2/8 of column to row 
the third grid was a 3/7 ratio
the forth grid was 4/6 ratio
and the fifth grid  was 5/5 ratio
These gave us a data base from which we could make nearly any color with our five tubes of color. 

I have used that grid scheme to test mixing glazes, clay bodies, root beers, ...  

If you did some grids with commercial underglazes on a slab of clay and fired it you would no longer have to speculate what happens if the underglazes are mixed.  


LT

Edited by Magnolia Mud Research
add conclusion

Share this post


Link to post
Share on other sites

The key to mixing underglazes is to ignore what you see while mixing. The fired sample is the only important thing, and it's often far from the raw color. I do some underglaze mixing, and it's always surprising how things come out. You an easily tint colors toward another color, but regular color theory doesn't apply. I've got a yellow that I make a little less intense by adding some orange in a a 6-1 ratio. I've got a cranberry red that is equal parts yellow-orange and burgundy, plus a little white. Some colors don't behave well with others, and it's easy to end up with a muddy mess. Some colors are also much stronger than others, so that a 50/50 blend ends up looking like a 90/10 mix after firing. The only thing to do is test, test, test. I do all my mixing by weight, because mixing by volume is very inaccurate when dealing with thick underglazes. Plus you can do very small test batches by weight. I also fire all of my tests with the clear glaze I plan on using on my work. I've just finished making a brown that is my cranberry red mix plus a little bit of black. You would expect it to be dark red, but for whatever reason the colorants decided to make brown instead.

As for the color you're trying to get, there's an Amaco Velvet called terra Cotta that would be a good place to start. Mixed with some orange it might get you close. I'm betting the Terra Cotta will be much stronger than the orange. A line blend would be a good starting point. If you're using Speedball underglazes, I start with an orange-brown-red mix, or orange-black-red. It only takes a tiny bit of black to have a big effect. Once you get the color you want, you can lighten it up with white.

Share this post


Link to post
Share on other sites
4 hours ago, neilestrick said:

 

As for the color you're trying to get, there's an Amaco Velvet called terra Cotta that would be a good place to start. Mixed with some orange it might get you close. I'm betting the Terra Cotta will be much stronger than the orange. A line blend would be a good starting point. If you're using Speedball underglazes, I start with an orange-brown-red mix, or orange-black-red. It only takes a tiny bit of black to have a big effect. Once you get the color you want, you can lighten it up with white.

Thanks. I have noticed the colors do not mix at all like acrylics and oil paints. I have tried the terracotta and know it will go straight to brown at cone 5. 

As I have the terracotta, I will get some orange and try different amounts of orange.  Wild guessing it, how many parts orange to one part terracotta to start? 

Does a line blend mean I increase whatever I am adding by linear increments? So I start with, say, x of terracotta and first I add y of the orange. Then the next sample is x of terracotta plus 2y of orange and so forth?

Share this post


Link to post
Share on other sites
10 hours ago, Gabby said:

Thanks. I have noticed the colors do not mix at all like acrylics and oil paints. I have tried the terracotta and know it will go straight to brown at cone 5. 

As I have the terracotta, I will get some orange and try different amounts of orange.  Wild guessing it, how many parts orange to one part terracotta to start? 

Does a line blend mean I increase whatever I am adding by linear increments? So I start with, say, x of terracotta and first I add y of the orange. Then the next sample is x of terracotta plus 2y of orange and so forth?

Line blends are usually done in 10% increments, so 90A/10B, 80A/20B, 70A/30B, 60A/40B, etc. With a little pocket scale you can do 20 gram tests, so you don't waste a lot of product. I use small plastic cups. Put the cup on the scale zero it out, weigh out the first underglaze color, zero it out, weigh out the second color. Just make sure you do't overshoot the second color or it can be tough to get it out without getting some of  the first color. If you weigh the lesser amount first it helps. The other option is to use a lid from a pint jar or mayonnaise jar and weight them out side by side, then mix.

Share this post


Link to post
Share on other sites

What about starting with red and yellow and getting the orange that way...or yellow red and your terra cotta. 

The grid by MMR is used to mix glazes and also cokorant and some random beautuful glazes can be foubd 

Greg Daly book Glazes and Glazing techniques"  ISBN 0-86-417502-7 goes into this in detail

Share this post


Link to post
Share on other sites

Hi gabby , something I’ve just recently learned is that some underglaze colours can’t be mixed and orange is one of them . I’ve recently purchased a lovely foxy orange colour underglaze but can’t remember the name , I’ll add the brand and colour for you next time I’m at our pottery shed . 

Share this post


Link to post
Share on other sites
7 hours ago, Carrick said:

Hi gabby , something I’ve just recently learned is that some underglaze colours can’t be mixed and orange is one of them . I’ve recently purchased a lovely foxy orange colour underglaze but can’t remember the name , I’ll add the brand and colour for you next time I’m at our pottery shed . 

I mix orange without any problems. What is the supposed reason for not being able to mix orange?

Share this post


Link to post
Share on other sites

Have you tried straight Red Art used like a watercolour? While you’re doing your line blends with your underglazes, try a little red art on a tile, both glazed and unglazed. I used to use it in small does when I worked cone 10, and it gets pretty smooth and glossy with nothing over it. If applied thinly, the end result was pretty close to the colour you want. 

Share this post


Link to post
Share on other sites
12 minutes ago, Callie Beller Diesel said:

Have you tried straight Red Art used like a watercolour? While you’re doing your line blends with your underglazes, try a little red art on a tile, both glazed and unglazed. I used to use it in small does when I worked cone 10, and it gets pretty smooth and glossy with nothing over it. If applied thinly, the end result was pretty close to the colour you want. 

I have never used Red Art. I will try to get some today. I use red clay, which I think you do also.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Sign in to follow this  

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.