Two-Ink Poster Proof: Title Lost at Three Metres
A student design team is producing a 70×100 cm two-colour poster for a small Tehran gallery. The budget covers black plus one spot ink on uncoated stock; the printer warns of 18% dot gain at 60 lpi. The title, «سکوت در حرکت», must be readable at 3 m under mixed tungsten and daylight. In the current proof the title is 60% black on a 50% warm grey field, while a 2 mm vermilion rule runs across the lower third. At 3 m the title disappears, although the rule remains conspicuous. The gallery director wants the poster to feel 'quiet' and refuses a full black background. One student proposes reversing the title out of black and moving the red rule behind it. A second student argues the red rule should become the dominant element because red advances. The team has one proof cycle left and must decide the final hierarchy without adding a third ink.
1. Diagnose why the title fails at 3 m while the red rule succeeds. Refer to value contrast, simultaneous contrast, and chromatic versus achromatic contrast.
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The title fails because its legibility depends on luminance contrast, and that contrast has collapsed. A 60% black on a 50% warm grey is only about a 10–15% value step before printing. With 18% dot gain on uncoated stock, the grey darkens toward the black, so the printed step becomes even smaller. At 3 m the eye cannot resolve fine hue differences, so the title reads as a low-contrast texture rather than a word.
The red rule survives for a different reason. Vermilion has high chroma against a desaturated warm grey, and it also has a value difference from the grey. Simultaneous contrast makes the grey appear slightly cooler or greener next to the red, which increases the red's apparent saturation. The rule is therefore conspicuous not because it is 'more important' but because it has stronger chromatic contrast and a clean, continuous edge. A squint test confirms this: the rule remains visible while the title turns into a grey band.
2. Propose a revised hierarchy using only black and one spot red, keeping the director's 'quiet' requirement. Specify approximate ink percentages and placement.
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Keep the quiet effect through low chroma, generous negative space, and restrained red area-not through low title contrast.
- Lower the grey field from 50% to about 20–25% black. This survives dot gain better and stays visibly lighter than the title.
- Set the title in 100% black on that light grey, or reverse it out of a black band that sits behind the title only. A band is not a full black background, so it satisfies the director's constraint while giving maximum luminance contrast. Avoid 60% black type on mid-grey entirely.
- Reduce the red rule from 2 mm to about 0.5–0.8 mm and move it to the lower margin, or replace it with a small red square or short tick. Keep red area under roughly 2% of the sheet so it accents rather than competes.
- Make the title the largest element, with clear space around it. The reading order should be title, image, then red accent.
The proof should be checked at 3 m under both lighting conditions. If the red still reads before the title, reduce red area or move it farther from the title, not merely darken the title.
3. The second student argues the red rule should become the dominant element because red advances. Evaluate this claim and state a decision rule for the final proof.
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The claim confuses perceptual salience with hierarchy. Red does tend to advance and attract attention, especially against a desaturated grey, but dominance in a poster should follow information, not retinal pull. A 2 mm horizontal rule carries no title, date, or image information; making it dominant would send the eye across the sheet and away from the title. It would also make the poster feel louder, contradicting the director's 'quiet' brief.
Decision rule: at 3 m and in a squint test, the title must be the first element perceived, the image second, and the red accent third. Red may remain the most saturated element, but it must not be the most visually dominant. If the rule still wins the squint test, reduce its length or area, lower its chroma if the ink allows, or move it to the edge. Do not solve the problem by adding a third ink or by making the whole background black.