Line drawings are the worst-case input for any style pass. A photograph has gradients and soft edges that a model can rebuild from; a clean ink drawing is almost nothing but edges, and edges are exactly what a style transfer tends to soften, redraw, or duplicate. If your finished passes keep coming back with doubled outlines or lines that went wobbly, the problem is the input, not the style you chose.
For quick experiments, the conversion tool on the homepage lets you run the same drawing through several settings and compare where the lines survive and where they break.
Scan at high resolution and keep the contrast clean
A style pass amplifies whatever is already in the file. Scan line art at 600 dpi if you can, and make sure the paper is genuinely white and the lines genuinely black rather than grey. A pencil drawing scanned at low contrast gives the model hazy edges to interpret, and it will interpret them differently in different parts of the image. Push the contrast so the line is unambiguous. This one step fixes a large share of "my outlines got fuzzy" complaints.
Decide up front whether you want the lines kept or rebuilt
There are two very different jobs and they need different settings. Keeping the original lines means the drawing's structure stays put and only the fill, color, or shading changes. Rebuilding means the model redraws the whole thing in a new style, and the lines are its own invention. Rebuilt lines look great for loose sketches and terrible for technical or architectural drawings, where a slightly different angle on a straight edge is instantly wrong. If your lines carry information, keep them. Only rebuild when the drawing is rough to begin with.
The doubling problem and how to avoid it
Doubled or ghosted outlines happen when the model draws its own edge close to but not exactly on the original one. Low-to-moderate strength settings reduce this a lot, because the model leans on the input instead of replacing it. Very high strength on line art is a reliable way to get that shadowed double-line look. If you need a strong new style on a detailed drawing, consider converting the drawing in sections so each pass has less structure to misread, then recombine the pieces.
Cross-hatching and fine texture
Dense hatching, stippling, and fine pencil shading are the hardest textures, because the pass sees thousands of tiny strokes and tries to interpret each one. The result is often a muddy texture where hatching used to be. Two options work. Keep conversion strength low so the hatching survives as-is, or flatten the shading to a simple grey before converting and let the new style supply its own texture. Trying to keep pencil shading and also apply a heavy new style fights itself, and the output looks it.
Flat color areas convert smoothly
The parts of a line drawing that are easy are the flat color regions between the lines. A solid fill, a sky, a plain shirt, or a block of background color will take a new style without any trouble, because there is nothing delicate to preserve. If your drawing is mostly line with small color areas, expect the color to convert beautifully and the lines to be the fragile part. Knowing which half of your image carries the risk lets you pick a strength setting that protects the lines even if it means a gentler style on the color. The reverse gamble, pushing strength for a bolder style at the cost of the lines, almost never looks right on a drawing.
Testing before committing
Before you run a finished drawing through a heavy pass, test the settings on a small crop that contains your tightest detail: a face, a fine hatch, a repeated pattern. A one-inch crop converts in seconds and tells you exactly how the pass treats your hardest area. If the crop survives, the full drawing will. If it does not, no amount of tinkering on the full image will rescue it, and you have saved yourself a long wait and a disappointing result. This is the single most useful habit for anyone converting line work regularly.
When redrawing beats converting
If the drawing is a clean technical plan, a logo, or anything where the exact geometry matters, a style pass is the wrong tool. Converted straight lines bow, right angles soften, and repeated elements drift out of alignment. For those, use the pass only on flat color and keep the original line layer on top in a normal editing program. The conversion gives you the fill and the mood; the original drawing gives you the geometry. That combination holds up far better than trying to make one pass do both jobs.
The honest summary is that line work rewards restraint. Clean input, moderate strength, and a clear decision about whether you are preserving or rebuilding will keep drawings from turning to mush. Run your worst drawing through the tool at two strengths, compare the edges at the size you plan to use, and you will see the pattern quickly.