algebra precalculus - Percent decrease in log space

I calculated the percent decrease of a value measured at two timepoints:

$\frac{t_1-t_2}{t_1} = d$

but I've now realized that the numbers I was given were log transformed, so it's not really correct to say, for example, that if $d = 0.6$ then the value decreased by 60%, since it's a 60% decrease in log space. I'm trying to figure out if there's a way to transform the $d$ I've already calculated into the correct value without recalculating using the untransformed $t_1$ and $t_2$. It seems like it should be fairly straightforward, but for some reason I'm having a hard time thinking about it. Maybe it's not as simple as I think. Is this an easy thing to do?