[pure-silver] Re: Phototec vs. Digital Truth

Thank you for taking the time to reply so thoughtfully to this thread.
I found this chart 
http://www.maco-photo.de/files/images/Development_Chart_161007.pdf , which 
credits you, with the suspect information on Rollei Retro 400 in D76. I've 
written to maco to point out the problem.

I will try 12 minutes as a starting poing with my 400 instead of 9.

Elias


 -------------- Original message ----------------------
From: Digitaltruth Photo <photosource@xxxxxxxxxxxxxxxx>
> The times listed in the Massive Dev Chart are a mixture of published  
> data and user contributions. There is information about the way that  
> conflicting information is resolved in the User's Guide which can be  
> accessed via the menu on the left. In  all cases the film  
> manufacturer's published data is given preference over other  
> contradictory data, unless there is a very clear case of the  
> manufacturer's data being unreliable.
> 
> Although the times for Rollei Retro and Agfa APX should be identical,  
> there have been changes made to the base of the Agfa film, and  
> different times have been published by Agfa in different countries  
> over the years. If you look at the current times published in the  
> Massive Dev Chart for APX 100 and APX 400 in D-76, they are 9 minutes  
> and 12 minutes respectively. There is an additional time of 10 minutes  
> listed for APX 400, which together with the 9 minute time shown for  
> APX 100 are both taken from publications prior to the change in the  
> film base. When the film base was changed, Agfa released one final  
> technical data sheet before the products were discontinued. This is  
> publication F-PF-E4_en-Agfa2003, and shows the new time for APX 400 in  
> D-76 as being 12 minutes. There is no data in this publication for APX  
> 100 in D-76. Despite the published change, many users reported that  
> the old times worked the same as before, so as always its up to each  
> individual to run their own tests based on these starting points. Both  
> the old and new times are shown in the Massive Dev Chart accordingly.
> 
> I haven't studied the Phototec chart in depth, but my first reaction  
> to seeing it was that the calculations all appear to be based on one  
> set of criteria, and as Martin Jangowski suggests, this could be very  
> misleading. The Ilford time/temp chart, which a version of can be  
> viewed from the left-hand menu of the Massive Dev Chart, offers the  
> same kind of general information. I'd be a little concerned about  
> directing people to Phototec's calculator as the implication is that  
> the times generated by it are factual rather than just extrapolations.  
> The times it shows might apply to linear development, but would not  
> work with many combinations unless the specific contrast curve of each  
> film and developer has been worked into the calculator. Somehow, I  
> doubt that.
> 
> --Jon Mided
> 
> Digitaltruth Photo
> www.digitaltruth.com
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