Can someone put this in film terms

From the MGIVRC data sheet


The speed of MULTIGRADE IV RC depends on the
filtration used during exposure. MULTIGRADE IV
RC unfiltered, has a paper speed of ISO P500.

mark said:

From the MGIVRC data sheet


The speed of MULTIGRADE IV RC depends on the
filtration used during exposure. MULTIGRADE IV
RC unfiltered, has a paper speed of ISO P500.

Click to expand...

ISO paper speeds have no direct relation to film speeds.

Just as there is an ISO standard for film speeds, there is also an ISO standard for paper speeds. Just don't ask me what that standard is (!) - no doubt it will be defined on the Web somewhere... ISO is the International Standards Organization.

Cheers, Bob.

Thanks Jay and Bob.

I meter my MGIV at ISO 6 and have acceptable results without any filtration. on a pinhole with an fstop around f/345, focal length of 100mm on a 'sunny 16' exposure its normally around 1minute 30seconds.

When putting a filter on it, I dont recall the exact numbers but I believe 0 - 3 all have a paper ISO around 200, and 4-5 are 100. Without a filter as mentioned its 500. Using these measures you can adjust your exposure accordingly, a #5 contrast filter puts the paper at 100 'iso' and a #2 puts it at 200 'iso' ..... at least in my experience doubling and halfing exposure has seemed to work just as it does with film ISO..

Thanks Christopher.