RBGs

[Cherry 6]

Is there a source of RBG values of commercial underglazes? I found one site but it only had the Amaco Velvets.  I'm thinking that if I had program with these, I could scan a design into the computer and use "bucket fill" to see how the colors work together. 

[Bill Kielb 1,125]

Interesting in that the color of glazes changes significantly depending on application, the clay underneath as well as the firing ...... how about scan in some pictures of those that you like and use this as a source for your palette just to get an idea? 

[neilestrick 4,606]

Colors do not behave in the kiln as they do with paint pigments. It all depends on the makeup of the glaze, firing temperature, kiln atmosphere, type of clay, and firing schedule. The rules of color mixing that apply to paints do not apply to glazes. Even with underglazes, blending colors requires test firing to see what the actual fired color will be, since oxides vary in strength. I've done numerous underglaze blends, and what you see before firing is rarely what you see after firing. It will also vary from brand to brand. As with most things ceramic, test, test, test. Line blends are a great place to start.

[oldlady 2,804]

hmmm..................  RBG, what could that be?   robin bluebird, grackle, rice, butter, green beans, richard, betty, george, ruby, beryl, garnet, rose, bellflower, geranium, wonder what RBG could be?

[liambesaw 2,765]

23 minutes ago, oldlady said:

hmmm..................  RBG, what could that be?   robin bluebird, grackle, rice, butter, green beans, richard, betty, george, ruby, beryl, garnet, rose, bellflower, geranium, wonder what RBG could be?

I thought it was Ruth Bader Ginsburg but I think they mean RGB which is Red Green Blue values for computer colors.

[Cherry 6]

RBG refers to the proportion of red, blue and green that are combined to create a color. They're used mainly on computer monitors and the web, but like the effects of different clays on the same glaze, differently calibrated monitors can give different hues, depending on how they are calibrated. It still gives a level of consistency in the appearance of an image, regardless of  the maker of your monitor or your program. 

 

 

[Mark C. 4,863]

I think its close to a waste of time for the below reason Neil said

(Colors do not behave in the kiln as they do with paint pigments. It all depends on the makeup of the glaze, firing temperature, kiln atmosphere, type of clay, and firing schedule. The rules of color mixing that apply to paints do not apply to glazes. Even with underglazes, blending colors requires test firing to see what the actual fired color will be, since oxides vary in strength. I've done numerous underglaze blends, and what you see before firing is rarely what you see after firing. It will also vary from brand to brand. As with most things ceramic, test, test, test. Line blends are a great place to start.)

 

Paint color and glaze color are apples and oranges

[Min 3,436]

Quick example of what Bill, Neil and Mark are saying, both the pots below use exactly the same stain, different claybodies and glaze / no glaze.  Same deal with underglazes using stains as colourants.

[Callie Beller Diesel 2,555]

Also, different base glazes will alter the colour of some stains. There is, unfortunately, no getting away from testing.

 

[Bill Kielb 1,125]

2 hours ago, Cherry said:

RBG refers to the proportion of red, blue and green that are combined to create a color.

I think everyone has said this is difficult at best and hard to standardize. Part of the “art” in the art of glazing is knowing and or discovering the nuances of a particular glaze combination, clay, firing, etc.... so your concept might seem counter creative to those who have spent years learning the art. Glazes are more like  CMYK, basically similar to how your printer works. Funny, your RGB screen gets translated to CMYK.

I still think for mockup purposes you could capture a picture of a fired glaze result and layer mask it into you drawing for a sense of what combinations might look like.

[JohnnyK 688]

One thing I can say with reference to my recently posted mosaic is that the Amaco Velvet underglazes that I used held pretty true to the colors as printed in the Amaco catalog  for the cones they are fired to...in this case ^6...

[Cherry 6]

Bill's final sentence is what I'm aiming for.  I realize the differences that various clays and firings have on the end result and I'm not looking for a perfect replication of a color.  I too, have spent years on glaze testing and color theory.  I'm not trying to invalidate the years of work that potters have done, just move my own in a different direction.  

I've made a chart of the underglazes I have. I also have a lot of colored pencils. I match the nearest pencil I have to the underglaze, then color in the printed design to see how the colors work together. If they don't, I start over. Colored pencils don't erase well.  I'm was hoping to ease the process of designing using an image manipulation program.  I've learned that Microsoft's 3D Paint will identify the RBGs from my chart, but won't save a palette of more than 18 colors. Which is more than enough. I'm also, finally, taking the time to watch GIMP tutorials. 

[neilestrick 4,606]

@cherry Are you looking at how specific glaze colors look next to each other, or overlapped with each other?

[Cherry 6]

I want a coloring book on my computer that uses my own images for the pictures, and a palette of underglazes for the colors. 

 

[Bill Kielb 1,125]

19 minutes ago, Cherry said:

I want a coloring book on my computer t

Gimp is free and quite capable. Lots of tutorials out there.