1-bit is right for coloring pages. It stores exactly 2 values per pixel — black and white — so a press prints solid lines with no in-between gray to screen into dots. Grayscale (8-bit, 256 levels) exists for photos and shaded artwork, where those in-between values carry real information; a coloring page's lines don't have shading, so grayscale only adds room for unintended gray edge pixels to survive.
What the two formats actually store
| 1-bit | Grayscale (8-bit) | |
|---|---|---|
| Values per pixel | 2 (black, white) | 256 (black to white) |
| Right for | Line art, no shading | Photos, shaded or airbrushed art |
| Edge pixels | Forced to pure black or pure white | Can sit anywhere in between |
| File size | Smallest | Larger for the same page |
The names describe how many bits of information each pixel carries — 1-bit meaning a single yes/no value, 8-bit grayscale meaning 256 possible shades. A coloring page's lines are drawn with intent to be either "line" or "not line," which is exactly what 1-bit represents; grayscale represents a spectrum the page was never designed to use.
Why grayscale line art still looks soft in print
An image can be saved as grayscale and still contain only near-black and near-white pixels almost everywhere — but "almost" is the problem. Anti-aliasing and export compression both introduce a scattering of true gray pixels along every edge (see the gray-pixel guide for why), and grayscale format has no mechanism to prevent that: any of its 256 values is valid, including the soft in-between ones a press screens into a visible dot pattern instead of a clean line edge. 1-bit removes the possibility entirely — a pixel is either fully black or fully white, so there is no gray value left for a printing press to reproduce as blur.
Why this isn't just a resolution fix
Increasing DPI does not fix a grayscale file's gray edges — a higher-resolution grayscale image still has gray pixels, just more of them along a longer edge. Resolution and color depth are independent settings. A coloring page needs both: enough pixels for the print size (300 DPI) and only two possible values per pixel (1-bit). Fixing one without the other still fails in print.
Order matters: threshold after resizing, not before
Converting an image to 1-bit and then resizing it reintroduces the exact problem 1-bit was meant to solve — standard image resizing blends neighboring pixels, which turns a clean black/white edge back into a blend of grays at the new size. The reliable order is: get the image to its final pixel dimensions first, then threshold to 1-bit last, so the two-value guarantee survives to the finished file. CrayonMill's cleaning pipeline treats this as a hard rule — gray-value pixels are never carried past the point where a page is thresholded to 1-bit.
Sources
Last verified 2026-09-04. Updated 2026-09-04.