Slip Colorant Percentages

[sheppard.lin]

Hi clay folks! I'm a technician at my local studio and we want to switch to a new colored slip pallette for some of our lessons. We currently work with a 3-5% mason stain addition. I want to make a navy blue, forest green, dark red, and mustard yellow. If you've made these colors, which mason stains (#s) work well, and what percentages do you use them at to get a vibrant color? 

I'll totally play with  line blends too, just thought I'd check if anyone has a good starting point! 

 

Lindsey 

[Rebekah Krieger]

Mason stains tend to be true to color. (Except for red, so getting an encapsulated red helps) 

i would recommend testing percentages maybe 3%, 5% 7% to see how it looks for intensity. 

[tinbucket]

One thing to note about colored slips - the more vitrified the slip is the more vibrant the color will be compare to a less vitreous slip with an equal percentage of stain. But the more vitreous your slip is the more problems you may encounter when matching shrinkage etc to your clay body. Green and blue are easy/cheap, I have used up to 20% stain to color a clay body. I would suggest doing a test of 5, 10, 15, and 20% stain additions to weight of dry material then narrowing it down from there. Red encapsulated stain is much more expensive and it might be wiser to use red underglaze instead of red slip or use the red slip sparingly. Below are some tests that some fine people have done adding stains to clay. Keep in mind their base is most likely very white and vitreous, which maximizes the potential of the stain addition. 
 

https://www.jakecorboy.com/colored-porcelain

https://glazy.org/u/derekau?base_type=400&analysisName=umfAnalysis