Re: using a scanner as a densitometer?

Hi Jack,

> How do we go about it on this list? <
It is basic densitometry, so I´d propose not to blow up the list with stuff that every reprography specialist has learned 100 years ago (and those gals ´n guys were damn good). There are lot of books about professional reprography and the first time you read them it´s a real eye opener.

The problem making density measurements with a scanner from alt-prints is that the prints have a very strange metamerism. That´s why several artists have shown their prints under changing ligthing conditions at e.g. Paris Photo -- it gives proper made metamerising alt-prints a 3D or moving look. It´ll be of my next very pleasurable tasks to make exactly this kind of prints and I´ll be more than glad to offer something such wonderful to someone who only knows "flat" silver gelatine or inkjet prints. This phenomenon is absolutely fascinating and it is one of my favorite projects.

But it´s also THE cause why making density measurements with a scanner is very critical. Basically: forget fletbed with fluorescent lighting for scanning alt. If you´re working with platinum you may be fine. If you work with cyanotpe you´l have a whole lot of problems. And if you work with something like cyanotype made for metamerising then definitely: forget it.

The fluorescent light of a scanner allows no proper density reading, esp. if the print was made for a metamerism trick. A drum scanner with a Halogen light source is good, with a special light source it can be very good.

The easies and cheapest way to get a halfway exact digital picture of an alt print is still (thougt this is common knowledge) to make a repro shots with a professional digital camera under so called "daylight conditions" paying attention to all repro basics. The light source used maybe special "daylight fluorescent bulbs" or (much better) special Halogen bulbs manufactured for repro/exhibition/museums.

All the best
  Kai

-------------- Jack Fulton schrieb: ---------------------------

> Say . . this is a fascinating topic that I'd like to learn more about.
> How do we go about it on this list?
> Jack Fulton
>
Received on Wed Feb 22 21:32:04 2006