Slips are always dull after glazing

[Crowknows]

Hi. I use shop bought slips then transparent glaze but they never come out as bright or full as the images on the sellers website. The reds are always pinky and black is grey. I've tried several different shop bought glazes and slips at earthenware and stoneware temps in my electric kiln, usually on terracotta earthstone clay. Is it just shop bought slips and glazes that are inferior? Any advice would be appreciated. Thank you.

[neilestrick]

Most manufacturers use white clay for their samples, as the colors will be the brightest and most colorful that way. Slips, glazes, and underglazes will come out darker in high iron clays.

[Crowknows]

Thank you. I'll try other clays

[Callie Beller Diesel]

If you like working with your earthenware, you can also try covering it with a layer of white slip before you apply the colourful ones. The background can help them pop better.

[Jeff Longtin]

I've had similar experience.  I've tried all the clays. (Slip cast anyway.) I find cone 6 porcelain to be the best foundations for color. 

It also depends upon thickness. To get a good strong opaque color you need to apply three coats of color.

Almost the opposite with the glaze. As thin as you can is best.  Clear/transparent glazes never seem to be crystal clear. (In my experience anyway.) I found dipping to be the best for clarity. Rubbing out any drips is also necessary.

As far as the colors themselves, I stayed with Amaco Velvet Underglazes, but even then I found that I had to do lots of testing.