White Slip vs White Underglaze as a Base?

[Ben xyz]

Trying to get a shiny red textured/stamped circle floating on unglazed, very dark clay body at cone 5. Since the piece is leather hard, I have the following options to consider:

A. Paint a white slip circle, bisque fire, then paint a red underglaze circle over it and follow with clear. Fire at c5.

B. Let greenware dry, paint a white underglaze circle, bisque fire, paint a red underglaze circle (over the white circle), followed with clear. Fire c5.

C. Let greenware dry, paint a red underglaze circle, bisque fire, follow with clear. Fire at c5.

D. Paint white slip circle on greenware, bisque, then paint gloss red glaze circle on top of white one. Fire at c5.

Which would you say would yield the best result to achieve the shiny red circle on very dark clay (both underglaze and glaze would be from Amaco).  Thanks!

[Min]

I would go with E.

E - make a few test tiles and see which you prefer.

I would probably start with trying the white underglaze on greenware then  red underglaze on top of that then bisque then glaze. (make sure each layer is dry before putting on the next) Is the underglaze compatible with the clear glaze? At the same time I would try the other options and see what happens. I'ld wrap up the piece (or put it in a ziploc if it fits) and wait until your tests are done. I know it can be tempting to just go for it but test tiles really are a good idea.

[Ben xyz]

4 hours ago, Min said:

I would go with E.

E - make a few test tiles and see which you prefer.

I would probably start with trying the white underglaze on greenware then  red underglaze on top of that then bisque then glaze. (make sure each layer is dry before putting on the next) Is the underglaze compatible with the clear glaze? At the same time I would try the other options and see what happens. I'ld wrap up the piece (or put it in a ziploc if it fits) and wait until your tests are done. I know it can be tempting to just go for it but test tiles really are a good idea.

Thanks Min - I like your E. Will try that one first. With a lot of iron and manganese in the clay, wasn't sure which material would hold up; sounds like the underglaze might be more dependable than slip in this case on the greenware. It also gives me the option of adding more post-bisque if and when needed. 

 

[Callie Beller Diesel]

+1 for E. They should all work to some degree, it’s just a matter of which look you prefer. When working with dark clay, adding a layer of something white, whether it’s slip or underglaze, underneath a colour does make it pop significantly. 

[Min]

When my sister worked for Dupont in the paint research dept they actually used a gray primer under red to make the red pop more. 

Edited January 27, 2023 by Min

[Roberta12]

@Ben xyz ++ for test tiles.  That is truly the only way you will know which method gives you what you are looking for.  All of your suggested methods should work, but will they achieve your vision?  I have used all of your ideas on porcelain, buff, white stoneware and dark brown clay.  I have my preferences and you will have yours! 

Post some pics when you get things fired!  Inquiring minds want to see!

@Min I am going to try the grey under red!  great info.

Roberta