Finally finished my first marbled bowl and it looks nothing like my sketch

I got hooked on marbled clay last winter after seeing a nerikomi demo, and my first few attempts had the same thing happen where the pattern I pictured never showed up on the surface. What surprised me was learning to judge the piece by the trimmed edges instead. If I cut a slice off the wall after trimming and the bands looked good there, I just accepted that the outside was going to do its own swirly thing. Some of my favorite mugs came out of exactly that kind of accident.

On the cracking, that's usually the two colors shrinking at slightly diffrent rates, or just uneven moisture between the layers. I started wrapping mine loosely in a grocery bag for the whole first week of drying and it made a real difference. Slow is the whole trick. I also try to join the colored sections at similar wetness, since one drier lump next to a softer one seems to invite cracks at the seam. One thing that helped my pattern survive was rolling the colored lump into a loaf first, then slicing off working pieces instead of repeatedly wedging the whole batch. Every handling smears the design, so I try to touch it as little as posible before throwing. Your plan for a whole set is a good one, beacuse each lump comes out different and the variety is half the charm.

I went through this exact cycle with agateware a couple years back and ended up switching methods entirely. Wheel throwing kept smearing my patterns no matter how softly I centered, so I started making thin colored slabs instead, layering them and pressing them together, then cutting forms from the laminate. You get way more control over where the bands end up, and you can build the pattern deliberately into the wall rather than hoping the wheel cooperates.

The drying cracks were my downfall too. My fix was covering the piece loosely with plastic for days longer than felt necessery, like a full week under an old towel in a plastic bin, before letting it finish in the open air. Since then I have only lost one piece out of maybe twenty to slow-dry cracking.

One thing that bit me later: colored slip bodies and plain stoneware shrink at slightly different rates, so a piece that survives the bisque can still check at glaze firing. I started using the same base clay body for both colors, just tinted with Mason stains, and the problem mostly went away. As for the muddled overwedge lump, I keep those around. Some of my favorite spoons and tester dishes came from exactly that kind of mud-colored mistake.

I'm more of a handbuilder so I don't know how much this transfers, but I did a similar thing with colored paperclay pressed into plaster molds. Same story where the surface got muddy looking but the cut edges were the best part. One thing I'm curious about since I've never thrown colored clay, does a clear glaze wash the pattern out at all? I've had thin slips go almost invisible under glaze before, so now I test every combo on a little tile first. Probably overcautious but tiles are cheap.

Fun how the cross-section ends up being the real payoff with this stuff. I had a similar thing with a spiral vase last fall. Outside was basially noise, but I shaved the foot ring down and the spiral curled through the bottom edge so neatly I left the base unglazed just to show it off. Might be worth planning a bare strip somewhere on yours for exactly that reason. Also curious what your two slips shrink to after bisque, mine always come out a couple shades duller than they look wet.