Single Filtration vs Dual Filtration

Are there any pros or cons with regards to using either single or dual filtration? Is it better to use one or the other and why? Why do paper manufactures have both values?

In theory, the dual filtrations (unlike single filtrations) don't require you to change exposure times when you switch between filtrations -- except maybe at high ones. In practice, some adjustment will likely be required, but you can use the same exposure time as a baseline. Otherwise, they're equivalent.

bvy said:

In theory, the dual filtrations (unlike single filtrations) don't require you to change exposure times when you switch between filtrations -- except maybe at high ones. In practice, some adjustment will likely be required, but you can use the same exposure time as a baseline. Otherwise, they're equivalent.

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exactly. this works nicely with Ilford MG in RC and FB in particular between G1 and G3 (the 'ballpark' for average'ish negs, so to say). G3.5 and 4 seem to be a bit 'faster', so I reduce time about 1/3 of a stop, while 4.5 and 5 usually require a new test strip.

Of course you might want to make a new test strip for every step of change in 'important' enlargements, but for 'general' stuff time consistancy thanks to dual filtration works like a charm for me.

The Ilford speed-matched filters and dichro-head settings are designed to keep a middle grey the same density in the print while moving the highlights and shadows around as the contrast is changed. For those of us who base print exposures on a highlight value, these settings are of little value, plus they add neutral density, which increases print exposure times. When printing VC, I don't even think in terms of a setting for a particular contrast grade anymore except as a starting point. After that, I add magenta or yellow as needed to get the contrast I need. Exposure for small increments just gets estimated (it gets refined later anyway). If I'm making a large change, I'll make a new test strip.

Best,

Doremus

bvy said:

In theory, the dual filtrations (unlike single filtrations) don't require you to change exposure times when you switch between filtrations -- except maybe at high ones. In practice, some adjustment will likely be required, but you can use the same exposure time as a baseline. Otherwise, they're equivalent.

Click to expand...

both require a change in exposure, unfortunately;no matter what the manufacturer says but dual filtration require less of an adjustment in my experience;other than that,no difference.