From: bjs@uts.amdahl.com (Barry Sherman)
Newsgroups: rec.photo
Subject: Re: Use Velvia at 32 or 40? (Was: Re: Fuji Sli
Date: 2 Sep 92 19:44:28 GMT
Followup-To: rec.photo
Organization: Amdahl Corporation, Sunnyvale CA

Jay Ts writes:

>konkkola@jyu.fi (Markku Konkkola) writes:
>: If you process Fuji Velvia according to Fuji standards then you should
>: expose it as 50 ISO-film. But if you process it according to Kodak 
>: standards (as we usually do) you should expose it as 40
>: 
>: E6-process standards are different: Fuji makes more shakes.
>
>Can you please elaborate on that?  Do you mean that Fuji specifies greater
>agitation?  If so, that would explain a lot...

I recently used the Kodak 6-step E-6 kit for the first time.  I was interested
in two points:

*  Kodak says to dilute the Reversal Bath concentrate 60% rather than using
   the entire amount of concentrate to make one gallon.  In reading the
   JOBO literature (their compendium of articles from their house-organ
   _Journal of Rotary Processing_) they stated that one should do this
   dilution *when processing Ektachrome films* and should not do so when
   processing Agfa and Fuji films.  I.e.  for Agfa and Fuji films one 
   should use the entire amount of concentrate to make one gallon.

   I followed JOBO's instructions and was quite pleased with my results.  Since
   I understand the chemical reversal step to go to completion, I suspect that
   this might not make much difference but it *does* appear to be a difference
   between "Kodak spec" and "Fuji spec".

   I also noticed that the title of the Kodak instruction sheet is "Instructions
   for developing Ektachrome films ...", making their instructions quite
   specific to Kodak emulsions.

*  Kodak, in their instructions, suggests a rather wide range of 1st developer
   times/temperatures when one is using a rotary processor.  Something like 
   "between 6 and 8 minutes at between 93 and 104 F".  In essence, they
   suggest some experimentation to determine what one's personal time/temp.
   should be.  

   JOBO recommended 6.5 minutes at 38C for the 1st developer.  Now, I had 40
   sheets of 4x5 E-6 (Velvia and 50D) and 8 rolls of 35mm (Velvia).  (Fairly
   productive vacation.)  The "serious" stuff was on 4x5 and the 35mm was 
   mainly snapshots and I really wanted the 4x5 to be as good as possible.  So 
   I tried developing one of the 35mm rolls first using the 6.5 minutes/38C 
   time/temp for the 1st developer.  I thought that they were just slightly 
   dark so I increased the time to 7 minutes and was pleased with the results 
   on the remainder of the film.  

   I noted that the Kodak instruction sheet recommended, if my memory serves 
   me, a two minuted extension of development time to push the film by 1 stop.
   So my 30 second increase would seem to have "pushed" the film by ~1/4 stop.
   This is really in the ballpark of shooting the film at 40 (I actually used
   50).

   An increase in development time would also correspond to an increase in 
   agitation, of course.

 Barry

 BTW - just last night I took a picture of a MacBeth Color Checker (on Fuji
	   50D) and developed it in the Kodak 6-step.  Color rendition seems
	   very good.  There is a very, very slightly pinkish cast to the 
	   two lightest (white) gray-scale squares of the color checker.  I
	   compared them with the lightest CC gel that I have - 2.5CC magenta -
	   and I'd estimate that the cast can be no greater than 1CC.  
	   This seems quite good to me and I'd expect that it's within the
	   realm of film variation even for a pro film.  I.e.  I doubt that 
	   the E-6 kit could do much better in producing accurate color.


-- 


|----------------------------------------------------------------------------|
| Barry Sherman, Amdahl Corp.       | "Any fool can face a crisis - it's     | 
| bjs@ruts.ccc.amdahl.com           |  this day-to-day living that wears you |
|                                   |  out." - Anton Chekhov                 |
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| Amdahl, being a corporation, is a legal fiction.  Therefore it is incapable|
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