A cel does not exist independently of its storage environment. Acid generated within the sheet must move through the cel, cross its surface, and enter the surrounding environment. What happens from there determines whether that environment continues to accept acid — or increasingly resists its removal.
The first three steps run identically in every enclosure. Only the fourth differs, and it is the one a collector controls. In all three animations below the cel generates acid the same way; the only thing that changes is the boundary condition outside it.
The default. A sealed sleeve, a tight portfolio, a conventional frame with the mat pressed against the glazing — anywhere the air next to the cel does not move and nothing removes what arrives there.
Watch the interior, not the air. As acid builds up outside, the difference driving outward transport shrinks, net emission slows, and newly generated acid stays in the sheet — where it accelerates the reaction that produced it. Note the generation multiplier climbing as that happens.
Move the air and the local concentration stays low. The difference driving outward transport stays large, and the cel keeps unloading indefinitely.
Ventilation has no capacity limit, which is its advantage. It also captures nothing — the acid is relocated into the room, which is only acceptable if the room can take it.
A scavenger holds the acid out of the air without moving the air. For as long as it has capacity, it does the same job ventilation does.
Note where this one ends. A saturated scavenger is not a weak scavenger — it is stagnation with extra steps. Capacity, not chemistry, is what sets a replacement interval.
Ventilation and absorption are not two different mechanisms. Both work by keeping the concentration at the cel surface low, and both fail the same way when they stop doing so. Stagnation is what the other two are measured against.
Which reframes the question worth asking about any storage method: not whether it has vent holes or absorbent board in it, but what boundary condition it creates at the cel surface — and whether it can hold that condition for as long as the cel keeps generating acid.
The same component at data-variant="preview", for the homepage row. Set data-href to make the whole card a link.