Dropper Bot
Spectral paint recipe solver
Dropper Bot turns a target color into drop-count mixing recipes for single-pigment paint palettes. Pick a Citadel color, a hex value, or anything you can sample, and get the closest mixes your set can physically reach, graded honestly.
Hobby ranges name hundreds of colors, but underneath they're all built from the same small set of real-world pigments. Dropper Bot maps every paint back to that pigment layer, simulates how pigments actually mix, and searches every combination of your palette for the closest recipe.
A Citadel preset, a hex value, or a color you sampled from a photo. The target becomes a precise point in CIELAB color space.
Hundreds of pigment combinations from your chosen palette are mixed spectrally using Kubelka–Munk theory, the same physics paint manufacturers use to formulate color.
Up to three distinct drop-count recipes, each graded by ΔE accuracy. When your set can't reach a color, Dropper Bot says so and recommends the one pigment that would fill the gap.
Screens mix light additively: blue plus yellow averages to gray. Paint mixes subtractively, through absorption and scattering, which is why blue and yellow make green at the wet palette. Averaging hex codes gives answers that look plausible and mix wrong.
Dropper Bot represents every paint as a reflectance curve across the visible spectrum and mixes in Kubelka–Munk space, so predicted recipes behave like real pigment. It also tells the truth about limits: on-screen colors are often more saturated than physical pigment can reproduce, so some targets overstate the paint they represent. You'll see that as a Best Effort grade instead of a pretend match.
Four paint lines today, matched against the full Citadel range. Because every paint maps back to its underlying pigments, any single-pigment or mixing-oriented line can join the library.
The reference palette: one pristine pigment per bottle, mapped to Color Index data for the most physically grounded predictions.
View list →All single-pigment colors from Golden's SoFlat matte acrylic line, sold in bottles. The Core palette covers 95% of available gamut with 9 bottles — coverage data shows steps 10–24 add less than step 3 alone.
View list →A complete subtractive core from Golden's ink-like High Flow line: two yellows, orange, two reds, magenta, two blues, and green plus white and black. Every Golden acrylic line is made from the same pigments, so this one palette covers Golden Fluid Acrylics too — there's no need to add a separate set. High Flow is more dilute and dye-like, so tinting strength shifts slightly between the lines, but the pigment identities are identical.
View list →An artist's signature set from Rogue Hobbies plus Pro Acryl white and black: vivid, high-chroma colors. Unlike the other sets here, this one is not a true single-pigment palette and Monument doesn't publish pigment numbers for it, so the identities are inferred and predictions are less reliable.
Where's Monument Expert Acrylics? Sadly it is not a true single-pigment mixing set.
View list →The nine confirmed single-pigment tubes from Scale75's 48-tube Artist range. The remaining 39 tubes are pre-blended at undisclosed ratios, so they're excluded — the model needs known pigment makeup to predict mixes honestly.
View list →More ranges join the library over time. Hex values shown for trademarked paint names are screen approximations used for identification only.
Our efforts are funded by contributions from users like you, which keeps Dropper Bot independent and lets the community steer what gets added next.
☕ Contribute to ongoing work by buying us a pot!Dropper Bot predicts paint mixing with spectral simulation; predictions are estimates and real results vary with brand, batch, and surface.
Citadel and Citadel Colour are trademarks of Games Workshop Ltd. Kimera Kolors is a trademark of Pegaso Models. ScaleColor is a trademark of Scale75. Pro Acryl is a trademark of Monument Hobbies. Golden and SoFlat are trademarks of Golden Artist Colors. Dropper Bot is unaffiliated with these companies and uses paint names nominatively to identify products.