DS07 — The Facsimile procedure: positioned graphic in the PDF layer

Trigger S4

The FES signature is to be visible — as with DocuSign: A positioned graphic on the signature line, at the right place, in the right size. E1 has generated three graphic variants (opaque PNG, transparent PNG, vectorized SVG) and asks: How does the right variant get to the right place?

The three graphic variants

All variants are located in the PII directory (Elektronische Unterschrift E1/, gitignored — never in Git) and are SHA-256-anchored for permanent use:

File	Format	Background	SHA-256	guid stamp
`E1.Signature.FES.png`	PNG 543×156	Gray (opaque)	`288bb187…428a5`	`01a09b48-4580-761f-…`
`E1.Signature.transparent.FES.png`	PNG 543×156 RGBA	Transparent	`d330348e…81fef`	`01a09b48-4580-7607-…`
`E1.Signature.transparent.FES.svg`	SVG (vectorized)	Transparent	`8fcffe0b…1006`	`01a09b48-4580-76f9-…`

Selection rule (from SIGNATURE_BLOCK.md):

Default: SVG — infinitely scalable, small (8 kB), ideal for positioned PDF layers.
Transparent PNG — if the renderer does not support SVG (some PDF generators, email clients).
Opaque PNG — only if the target format does not support transparency (the gray area would be visible).

Display sizes

The facsimile graphic in example E1 is a 543×156 px asset (aspect ~3.48:1):

height	Size @96 dpi	Usage
`40`	~10.6 mm high, ~36.7 mm wide	Standard for signature lines
`24`	~6.4 mm high	Compact variant (tight layouts)
`300`	~79 mm high	Full-format view only — not for signature lines

The target size for the PDF layer is 35–45 × 9–12 mm — handwritten standard size. The SVG supports this size without pixel loss; the PNGs support print up to ~45 mm width @300 dpi.

HTML embedding

In the Markdown doc (Typora-compatible, template SIGNATURE_BLOCK.md):

<div style="text-align:left">
    <img
        src="file:///mnt/vm1/data/org-partner/pii/signature-ad/E1.Signature.transparent.FES.svg"
        alt="Unterschrift/Signature Erich Mustermann (E1)"
        height="40" />
</div>

The signature line (________) comes before the graphic, with name and function below it — exactly like a handwritten signature.

PDF layer: positioned graphic (DocuSign-style)

In a PDF, the graphic is absolutely positioned — via a signature appearance layer (PAdES):

%%{init: {'theme':'base','themeVariables':{'primaryColor':'#FBFAF7','primaryTextColor':'#0F1B33','primaryBorderColor':'#6B7280','lineColor':'#6B7280'}}}%% flowchart TB A["PDF-Dokument
(FES-Verfahren)"] --> B["Seite n
Signaturbereich"] B --> C["Signaturplatte
(DS08: Zertifikat, Hash, Zeitstempel)"] B --> D["Positionierte Grafik
Facsimile SVG/PNG, 35-45 x 9-12 mm"] C --> E["PAdES-Signatur
(kryptographisch gebunden)"] D --> E

The graphic is the visible feature; the cryptographic binding (signature plate, DS08) is the proof mechanism. DocuSign combines both — the graphic above the signature line, the cryptographic signature in the PDF structure.

Coordinate principle

Positioning follows the DocuSign principle: The signature container (in the PDF: signature field) has fixed coordinates (x, y, width, height); the graphic is positioned within the field:

Element	Position	Size
Signature field	x, y (page n)	~50 × 20 mm
Facsimile graphic	Field + inner padding	35–45 × 9–12 mm
Signature line	Field base	Field width
Name/function	below the line	8–9 pt
Signature plate (DS08)	beside/below the graphic	8 pt

The graphic is the visible feature — not the proof

Important for saga quality (and a common misunderstanding):

The facsimile graphic alone is a simple eS. It "proves" nothing — it shows the signature. The proof lies in (a) the text-form chain (Part I: signature doc + events + SHA-256) and (b) the cryptographic binding (Part II: PAdES, DS08).

Therefore the labeling rule applies: embed the facsimile only if the doc is marked as "digitally signed" — otherwise the graphic suggests a legal validity that the chain does not (yet) carry.

Verification before every embedding

sha256sum E1.Signature.transparent.FES.svg
# → muss übereinstimmen mit:
#   - SIGNATURE_BLOCK.md (Tabelle, 8fcffe0b…1006)
#   - Sidecar .v7g.md (gleiche SHA)
#   - evidence.facsimile_ref.sha256 im Signatur-Doc

Deviation = wrong version/tampering → do not use, check back with E1. The SHA-256 is the proof of originality (identification always and everywhere — even when the graphic moves); the guid stamp is only a deterministically reproducible reference feature (gc-v7guid gen-doc).

Summary

Three graphic variants (opaque/transparent/SVG) with a fixed selection rule; the default is the scalable SVG.
Signature lines: height="40" (~10.6 mm); target size for the PDF layer 35–45 × 9–12 mm.
The graphic is the visible feature; the proof lies in the chain (Part I) + cryptographic binding (DS08).
Next article (DS08): the signature plate — certificate, hash, timestamp.

Created: 260913 | Part II, article DS07 | Series: digital-signage