Acid transport from a cel surface to a scavenging board. Pick a frame and a strip level to see where concentration builds and whether the board can keep up.
Pick a common cel size or enter your own, then describe the stack.
No spacer and the top mat lies on the glazing: its band has no gas over it and stops being a sink.
One window size per stack. Three sheets cut to the same opening is one entry, not three. The bottom mat sets the rear gas gap: its total thickness is the space the cel sits above the backing board.
Thickness is estimated as ply ÷ 64 in per sheet — the trade nominal. Real board runs a few percent either side of that depending on maker, so if you have measured your stack, choose Custom and enter it.
Hydrolysis speeds up with heat and moisture, so the source is scaled from the conditions the cel was measured at to the conditions it will be stored in. Activation energy 95 kJ/mol gives roughly 2.1× per 10 °F. Both that and the RH exponent are literature values, not measured here. The reference defaults to 72 °F and 50% RH, the conditions the CelNexus jar testing was run at.
The source is taken as measured. The derating factor is applied to the board, because that is where the uncertainty is.
Deposition velocity is not measured. Compare configurations against each other with confidence; treat absolute values as provisional.
Pass and fail are measured against a build that has kept level-1 cels without incident. That single observation covers the board’s capacity AND its surface kinetics, which is why neither φ nor v_d appears in any verdict below. Change these only if you have a different build you trust more.
Tick it for ArtCare, MicroChamber or any equivalent acid-absorbing board. Leave it unticked for ordinary matboard, which is treated as doing nothing.
A background covers the board behind the cel, so acid has to travel out to the window edge instead of straight down. It is the costliest choice on this card.
From CelNexus jar testing at 72 °F / 50% RH. A 24 h jar measures the pool already in the film, so treat these as upper bounds on sustained emission.
These explain the verdict above rather than adding to it. Nothing here passes or fails on its own.
The only check that can rule out a steady state. If the cel emits faster than the reachable board can take at its ceiling, no finite concentration exists and nothing downstream matters.
Only meaningful once Gate 1 passes. Colour is absolute and keyed to the allowable, so the same shade means the same thing on both maps and between any two enclosures.
vd is the least certain input in the model. This sweeps it and shows whether the board band is sized by the absorption length λ or by the physical band. Where λ binds, a slower board simply reaches further and recruits more area; where the band binds, that compensation is unavailable and results degrade in full proportion.
Gas entering the board band is absorbed over a length λ = √(D·gap/vd). Band beyond about 2λ adds capacity but not speed.