How do you get the stencil ink to blend smoothly without lines?

The band usually happens because you're butting the colors up against each other instead of overlapping them. With an ombre like yours, blend from both ends: start your pink at the top and come down about a third, then start your purple from the bottom and come up, and keep working each color into the overlap zone until there's no seam. The middle third is where both brushes meet and the colors mix themselves. If you only ever apply each color in its own zone, you'll always get that hard line right at the border.

Two brushes is honestly workable if you're disciplined about it. Use one for the warm end (pinks, corals) and one for the cool end (blues, teals, purples), and give them a swipe on scrap paper between colors so you're not dragging leftover pink into your teal. Cross-contamination makes colors go muddy more than it makes bands, but a dirty brush definitely doesn't help. A third brush or even just a couple of cheap finger daubers for the in-between shades would give you more freedom, but don't feel you need a full set.

Paper does matter some. Basic white cardstock works fine, but a smoother, slightly heavier one takes blended ink better and shows fewer blotchy patches. If your current stock is very absorbent, the ink soaks in fast and dries before you can soften the seam, which makes the band worse. Nothing fancy needed, just something with a smoother finish if you can grab it.

Five colors can absolutely work, just order them so neighbors are related. Pink into purple into blue into teal reads as a smooth shift. If you jumped from pink straight to teal you'd fight a battle no brush technique can fix. And work light to dark on the page, since the darker shades cover better and you can nudge the light ones back with less muddying.

One last trick: once both colors are down in the overlap area, go back over that zone with the lighter color's brush only, almost no ink on it, small circles. It knocks down the transition line surprisingly well.

I had the same problem when I tried a sunset thing on a bookmark and it turned out the brushes were way too loaded. I kept going back over the seam with fresh ink and making it worse. Now I tap most of it off first and build up relly slow, like barely any color at a time. It feels silly but the bands got way softer. Do you wait for each color to dry a bit before starting the next one, or keep going while it's wet?

Been doing ombre panels since back when we all used cut-up kitchen sponges and those old foam stipple brushes, and one trick from those days still works better than anything. Make the middle shade yourself. Scribble a little of each neighboring ink onto an acrylic block or a plastic lid, pick it up with a nearly dry brush, and tap that blend color straight into the seam zone. Two 'official' inks plus a hand-mixed go-between hides a world of sins. I still do that on big background stencils even now. Also try rotating your card 180 degrees halfway through the overlap and working from the other side, it evens things out more than you'd think.

One thing that finally fixed it for me was doing a full pass with a neutral first. I stencil the whole shape in the palest shade, like the lightest pink, before touching any other color. Gives every other color something to grab onto so nothing sits on bare paper, and the transitions stop fighting each other. Also, I stopped trying to blend through the stencil and took it off before softening anything. Blending on the open card with a clean dry brush lets you see the actual seam instead of guessing through the cutout. Took me way too long to figure that part out.

This is kind of reassuring to read as someone who mostly does gradient backgrounds on canvas totes instead of cards. Fabric seems way more forgiving than cardstock, or maybe I've just been lucky. One thing I noticed though, my stencil openings are pretty small so there's barely any room to work the colors together inside the letter shapes. Does anyone find that tiny stencil windows basicly force a hard line no matter what you do? Wondering if I should cut a bigger opening myself or just accept it. Also still figuring out which brushes to even buy, there are so many kinds and I don't want to waste money on the wrong ones.