Archived posting to the Leica Users Group, 2004/08/02
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Adam- This may be late as a reply, but I'll give you the info I picked up over the years. As you know, film is predominately sensitive to blue light, so to make B&W film panchromatic, the manufacturers added a photoreative dye that absorbed the blue light, and allowed a more balanced sensitivity to the film overall. This dye is in a 'leuco' or colorless state until it is activated by some developers that have what are know as 'coupling' activity. There are several developers that can couple the leuco dyes- Para-aminophenol, the developing agent in Rodinal is one well known example- it couples the dye into a water soluable 'analone' (as opposed to an insoluable analine) dye, and the effluent from a development with Rodinal looks like grape Kool-Aid! The purple color is telling you that the dveloper is working! The results you seem to be getting is typical- some modern developers use phenylinediethalamine as a developing agent, and it too is a coupling agent, and may color the effluent- it is nothing to worry about- in fact, if I did a tank of film in Rodinal- which I like a lot, and didn't see the color purple when I dumped it, I would be very worried! Best of light to you1 Dan ----- Original Message ----- From: "Adam Bridge" <abridge@gmail.com> To: "Leica Users Group" <lug@leica-users.org> Sent: Sunday, August 01, 2004 3:36 PM Subject: [Leica] Attack of the purple chemistry: JOBO, T-MAX, and XTOL > I fired up the newly-acquired JOBO ATL-1000 yesterday, popped in a > roll of newly shot TMAX-100, loaded up the XTOL (a few months old but > stored in an air-free accordian bottle) and after figuring out how to > get something of about the right processing time I turned it loose. > > The results appear to be okay (I was using 1:1 XTOL and the Kodak > recommended times as a starting point) but the effluent chemistry was > a most definite PURPLE. Was the chemistry bad? I've had batches of > Tri-X that resulted in purple chemistry but not THIS purple. > > What gives? > > Adam > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information >