Hi sretodd,
Dunlop and Talalay aren’t directly comparable in terms of firmness using only ILD numbers because there are several factors that can affect how soft or firm a mattress (or an individual layer) feels besides just the ILD of the material (see post #4 here) and Dunlop and Talalay that are the same thickness and ILD won’t feel the same in terms of their firmness for most people because they have a different response curve and compression modulus (how quickly a material becomes firmer as you sink into it more deeply). There is more about the difference between Dunlop and Talalay in post #7 here.
Generally speaking, if a piece of Dunlop and Talalay were both rated at a 19 ILD, the Talalay would feel softer by comparison.
Phoenix