I may have covered this previously, but if you noticed a different tonal color to the prints, it has to do with bleaching. A bleached print will be more cooler toned, while a non bleached print will have a very warm color to it. You'll notice that these two that I picked for this blog post are very warm toned. They were not bleached at all.
|Fabriano Acquarello Cold Press|
|Fabriano Acquarello Hot Press|