Archived posting to the Leica Users Group, 2012/08/13
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Mark Rabiner <mark at rabinergroup.com> wrote: >... in the last decades of darkroom work in the last half of the century the > toner which dominated was selenium... Light selenium toning was my standard also, and was the print tone I first tried to match with the digital B&W printing technology, in part, because I was hanging shows of mixed silver and inkjet pigment prints. >... > A serious print collector or gallery would expect this. Prints without a > hint of green in it. It was not optional. This issue -- avoiding a greenish tint -- is what caused me to pursue the 100% carbon pigment print technology. What we initially thought were top notch dedicated B&W "carbon" pigment prints were turning greenish (negative Lab A values) in only 3 years of commercial gallery level light (according to accelerated test data). The problem was (is) that the third party B&W inkset makers can't get the best color pigments. They can get excellent carbon. The third party players also have not carefully matched the fade rates of the cyan and magenta pigments. Typically, they use magenta and cyan to cool the warm carbon tone. The magenta fades more quickly, causing the stronger cyan to turn the prints greenish. Ultimately, all of even the best color pigments from the OEMs will fade faster than the carbon, causing "neutral" prints to warm. Thus, again, the 100% carbon pigment approach appears to be the best for those who want the very best B&W image stability. (It can also be very cheap.) On page 2 of http://www.paulroark.com/BW-Info/Eboni-6.pdf I summarize some of the data generated by http://www.aardenburg-imaging.com/ (the most thorough testing, in my view) to show some of the relative fade & (mostly) tone-shifting that is going on with different approaches. Paul www.PaulRoark.com