1. Historical Context: Why Fogra 39 Had to Evolve
Fogra 39 (characterization data FOGRA39, commonly distributed as the profile ISO Coated v2 (ECI)) was published in 2004 under ISO 12647-2:2004. At that time, commercial printing papers contained little to no optical brightening agents (OBAs).
Over the next decade, paper mills drastically modernized their production recipes. Modern commercial stocks became significantly brighter, whiter, and bluer due to the heavy inclusion of fluorescent optical brighteners. As a result, prepress operators encountered a severe problem:
The Visual Metamerism Dilemma:
A hardcopy proof made on traditional OBA-free proofing paper matched the spectrophotometer readings under classic D50 viewing booths, but side-by-side with the final production run on modern bright paper under ambient daylight or LED lighting, the colors looked completely mismatched.
In 2013 (with characterization data finalized in 2015), the European Color Initiative (ECI), Fogra, and BVDM released FOGRA51 (PSO Coated v3) alongside its uncoated companion FOGRA52 (PSO Uncoated v3) to accurately model modern substrates.
2. Technical Comparison Matrix: Fogra 39 vs Fogra 51
| Property | Fogra 39 (ISO Coated v2) | Fogra 51 (PSO Coated v3) |
|---|---|---|
| Underlying ISO Standard | ISO 12647-2:2004 | ISO 12647-2:2013 |
| Substrate Category | Paper Types 1 & 2 (Gloss & Matte Coated) | Premium Coated (PS1 - Coated Paper) |
| Paper White Point (L*a*b*) | L*: 95, a*: 0, b*: -2 (Warm/Neutral) | L*: 95, a*: 1.5, b*: -6 (Bluer/OBA-rich) |
| Measurement Lighting | M0 (Standard Illuminant A, unpolarized) | M1 (D50 with defined UV component) |
| TAC / Total Ink Limit | 300% (330% in original FOGRA39 dataset) | 300% (Strictly standardized) |
| Tone Value Increase (TVI) | Curve A (14% at 50% dot) | Equalized Curves (16% at 50% across CMY) |
3. The TAC Limit Reality: 300% vs 330%
One of the most consequential operational differences between the profiles lies in ink density management.
While the official ECI profile ISO Coated v2 300% (ECI) clamped coverage to 300%, many legacy installations ran the original ISO Coated v2 profile which allowed up to 330% TAC. Under modern high-speed presses with speeds of 15,000–18,000 sheets/hour, 330% ink coverage creates immense risk:
- Excessive Anti-Set-Off Powder: Press operators are forced to spray thick starch powders to keep sheets separated in the delivery pile, leaving a sandpaper-like gritty texture on the printed piece.
- Lamination Failure: Over-powdered or overly wet inks prevent thermal and OPP film laminates from adhering, leading to bubbling and edge peel.
Fogra 51 strictly enforces 300% maximum TAC. This guarantees clean drying, eliminates set-off risks, and minimizes pigment consumption without sacrificing black saturation.
4. What About Uncoated Paper: Fogra 47 vs Fogra 52
When migrating from Fogra 39 to Fogra 51, you must also update your uncoated standard:
- Legacy Uncoated:
FOGRA47 (PSO Uncoated ISO12647). Often suffered from weak black rendering and severe color shift when proofed on modern bright papers. - Modern Uncoated:
FOGRA52 (PSO Uncoated v3). White point is tuned toL*: 93, a*: 2.5, b*: -10with a strict 280% TAC limit.
5. How to Safely Convert Artwork from Fogra 39 to Fogra 51
Never blindly apply Edit > Assign Profile in Photoshop! Assigning a profile keeps raw CMYK numbers unchanged and shifts all printed colors toward yellow/green.
Instead, follow standard prepress color conversion:
Method A: DeviceLink Profile Conversion
Use an official Fogra 39 to Fogra 51 DeviceLink profile. DeviceLink conversion protects pure Black (K) text channels (preventing 100% K body copy from turning into 4-color mud) while re-separating rich colors to comply with the 300% TAC ceiling.
Method B: InkCheckHero 1-Click Preflight & Auto-Fix
Inside Adobe Photoshop or Illustrator, select the Fogra 51 preset (300% TAC) in the InkCheckHero plugin. The engine mathematically inspects every pixel, highlights overflows, and automatically extracts excess CMY into a non-destructive correction layer.