Digital Truth Massive Dev Chart

stevebrot · 10-05-2010, 10:13 PM

Originally posted by HGMonaro

the Foma site (pdf) doesn't specific different times for different formats so I think you'd start with the times shown. The data for the sheet film seems odd, same time and film speed as the roll film when used 'stock' but different when diluted 1:1

Yes, the data for the sheet film seems very odd. It was that and similar entries that prompted this thread. I shoot Arista.EDU Ultra/Foma 100 in 4x5 and while I don't use D-76, I would suspect that 10 minutes with the 1:1 dilution at 23C would thoroughly cook the Foma emulsion.

Edit:
Oops! I just realized that the 10 minutes at 23C is to push to ISO 200. That time/temp/dilution combination is much more believable.
/Edit

Steve

Last edited by stevebrot; 10-06-2010 at 11:31 AM.

brofkand · 10-06-2010, 05:04 AM

Originally posted by HGMonaro

the Foma site (pdf) doesn't specific different times for different formats so I think you'd start with the times shown. The data for the sheet film seems odd, same time and film speed as the roll film when used 'stock' but different when diluted 1:1

That makes sense. Stock is straight out of the bottle (a gallon of D-76 just mixed, for example). 1:1 is half D-76 and half water.

When you dilute 1:1, you have to increase development time.

HGMonaro · 10-07-2010, 08:38 PM

Originally posted by brofkand

That makes sense. Stock is straight out of the bottle (a gallon of D-76 just mixed, for example). 1:1 is half D-76 and half water.

When you dilute 1:1, you have to increase development time.

In general yes.

The MDC has (film, developer, dilution, EI, time, temp)

35mm
Fomapan 100, D-76, 1+1, 100, 10, 20C

Sheet
Fomapan 100, D-76, 1+1, 200, 10, 23C

So... seems I missed the difference in temp... 'they' are claiming 3C hotter will get double the filmspeed on the different base substrate (35mm vs sheet). Would need to try it to find out.

Cheers, Nige

stevebrot · 10-07-2010, 11:34 PM

Originally posted by HGMonaro

...'they' are claiming 3C hotter will get double the filmspeed on the different base substrate (35mm vs sheet)...

It does sound like a bit of a stretch and it may depend on the method of processing for the sheet film...tray vs. rotary drum vs. deep tank and the type of agitation used. The Foma emulsion adds density quickly with standard developers, so it may well be that the additional temp could result in a 1 stop push in speed.

Steve

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10-05-2010, 10:13 PM	#31
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007 Original Poster	Originally posted by HGMonaro the Foma site (pdf) doesn't specific different times for different formats so I think you'd start with the times shown. The data for the sheet film seems odd, same time and film speed as the roll film when used 'stock' but different when diluted 1:1 Yes, the data for the sheet film seems very odd. It was that and similar entries that prompted this thread. I shoot Arista.EDU Ultra/Foma 100 in 4x5 and while I don't use D-76, I would suspect that 10 minutes with the 1:1 dilution at 23C would thoroughly cook the Foma emulsion. Edit: Oops! I just realized that the 10 minutes at 23C is to push to ISO 200. That time/temp/dilution combination is much more believable. /Edit Steve Last edited by stevebrot; 10-06-2010 at 11:31 AM.

10-06-2010, 05:04 AM	#32
brofkand Pentaxian Join Date: May 2009 Location: North Carolina Posts: 836	Originally posted by HGMonaro the Foma site (pdf) doesn't specific different times for different formats so I think you'd start with the times shown. The data for the sheet film seems odd, same time and film speed as the roll film when used 'stock' but different when diluted 1:1 That makes sense. Stock is straight out of the bottle (a gallon of D-76 just mixed, for example). 1:1 is half D-76 and half water. When you dilute 1:1, you have to increase development time.

10-07-2010, 08:38 PM	#33
HGMonaro Veteran Member Join Date: Apr 2007 Location: Melb. Aust Posts: 840	Originally posted by brofkand That makes sense. Stock is straight out of the bottle (a gallon of D-76 just mixed, for example). 1:1 is half D-76 and half water. When you dilute 1:1, you have to increase development time. In general yes. The MDC has (film, developer, dilution, EI, time, temp) 35mm Fomapan 100, D-76, 1+1, 100, 10, 20C Sheet Fomapan 100, D-76, 1+1, 200, 10, 23C So... seems I missed the difference in temp... 'they' are claiming 3C hotter will get double the filmspeed on the different base substrate (35mm vs sheet). Would need to try it to find out. Cheers, Nige

10-07-2010, 11:34 PM	#34
stevebrot Otis Memorial Pentaxian Join Date: Mar 2007 Location: Vancouver (USA) Photos: Gallery \| Albums Posts: 42,007 Original Poster	Originally posted by HGMonaro ...'they' are claiming 3C hotter will get double the filmspeed on the different base substrate (35mm vs sheet)... It does sound like a bit of a stretch and it may depend on the method of processing for the sheet film...tray vs. rotary drum vs. deep tank and the type of agitation used. The Foma emulsion adds density quickly with standard developers, so it may well be that the additional temp could result in a 1 stop push in speed. Steve