How to Use This Tool
Validate CSS hex colors and create a deterministic proof-sheet manifest. Validate named hex colors, arrange a printable swatch grid, show RGB labels and screen-to-print limitations, then export a reusable proof manifest.
The work this page finishes
A palette on screen does not create a labeled physical proof; printers and brand teams need repeatable placement plus exact source RGB values beside each patch. For Color Swatch Sheet, the row-preserving workspace makes a correction repeatable without rebuilding a prompt or transmitting the source file.
Deterministic workflow
Accept only six-digit CSS hexadecimal colors, derive their three sRGB byte values and assign each valid swatch to a deterministic row and column of the selected physical size. For Color Swatch Sheet, this page accepts at most 5,000 records and 2 MB of text; rejected items retain their row references while valid items remain available.
Why a dedicated interface helps
Print the browser sheet at 100% scale and compare it under the intended conditions; the manifest preserves source values when printer profiles or stock change. For Color Swatch Sheet, immediate recalculation and a stable export are useful when the same rule must be applied consistently across a list instead of explained one item at a time.
Assumptions
- Six-digit hex is the authoritative input notation.
- Browser print scaling is set to 100%.
- Physical color approval requires a managed print workflow.
For Color Swatch Sheet, retain the original source until the destination accepts the result; processing stays in this tab, although the device and installed extensions remain part of the user's security boundary.
Limitations and review boundary
CSS colors are screen sRGB instructions, not measured CMYK or spot-color proofs; browsers, printers, profiles, ink, paper and scaling can change appearance. For Color Swatch Sheet, no supplied URL is requested and no pasted markup or code is executed; output is inserted through text-only DOM operations.
Verification and provenance
The implementation was checked against W3C CSS Color Module Level 4 on 2026-08-26, with fixtures for a known answer, an invalid input and a batch-specific edge condition. Four valid example colors at two columns produce two labeled grid rows with exact hexadecimal and RGB values.
Sources & assumptions
Tool Spec v2 · verified 2026-08-26. Platform rules and fees can change; the editable inputs remain authoritative for your account.
Official references
- W3C CSS Color Module Level 4 (checked 2026-08-26)
Model assumptions
- Six-digit hex is the authoritative input notation.
- Browser print scaling is set to 100%.
- Physical color approval requires a managed print workflow.
- CSS colors are screen sRGB instructions, not measured CMYK or spot-color proofs; browsers, printers, profiles, ink, paper and scaling can change appearance.
