Duotone (.fduotone)
Portable printing inks, preview colours and coverage curves.
Reviewed against the application source on 5 October 2026. Focale is in active development; available commands and published packages may differ by build.
Use in the application
Image → Mode offers Load duotone options and Save duotone preset for a duotone document. Loading replaces the ink interpretation of the gray plate as one undoable change.
File structure
settings contains one to four inks in order. Each ink has a trimmed name, an opaque ARGB color and a Base64 curve of exactly 256 coverage bytes. Optional photoshopData retains the original Adobe payload. Resolved colour-book colours travel with the file.
| Field | Value |
|---|---|
| Extension | .fduotone |
| format | focale-duotone-preset |
| version | 1 |
| Photoshop | .ado |
{
"format": "focale-duotone-preset",
"version": 1,
"settings": {
"inks": [
{
"name": "Black",
"color": 4278190080,
"curve": "AAECAwQFBgcICQoLDA0ODxAREhMUFRYXGBkaGxwdHh8gISIjJCUmJygpKissLS4vMDEyMzQ1Njc4OTo7PD0+P0BBQkNERUZHSElKS0xNTk9QUVJTVFVWV1hZWltcXV5fYGFiY2RlZmdoaWprbG1ub3BxcnN0dXZ3eHl6e3x9fn+AgYKDhIWGh4iJiouMjY6PkJGSk5SVlpeYmZqbnJ2en6ChoqOkpaanqKmqq6ytrq+wsbKztLW2t7i5uru8vb6/wMHCw8TFxsfIycrLzM3Oz9DR0tPU1dbX2Nna29zd3t/g4eLj5OXm5+jp6uvs7e7v8PHy8/T19vf4+fr7/P3+/w=="
}
]
}
}Validation and limits
Maximum 128 KiB, one to four inks, 63 UTF-16 units per name, exactly 256 bytes per curve and at most 64 KiB of Adobe payload. Missing, unknown or invalid data rejects the whole file.
Photoshop interchange
ADO is import-only in the preset workflow. Matching-system inks need the corresponding imported ACB book to resolve their colours. Once saved as .fduotone, those resolved colours and native curves no longer require that book.
Complete format references
Download the full Markdown specifications in English, including schemas, validation rules and compatibility details.