Topic: Long exposure / multiple exposure

[sparx]

I'm planning some very long exposure shots up on the coast and read in an old Black & White magazine article someone who got similar results by taking multiple exposures. Now I know the concept of the long exposure, take a reading, add reciprocity failure, take the picture. But what's the math on multiples?

Say I had an exposure of 15 seconds with everything taken into account. Is it just a case of taking 15 1 second shots or do I have to reduce or lengthen each subsequent picture on some logarithmic scale or something? The former seems logical to me but what do I know!

Also on the subject, has anyone tried either the new Ilford Pan 50 or the Rollei (MACO) Pan 25 films. Any advise on use and developing would be appreciated. Ta

[LT]

good to see you back -

I often use multi exposures, it can retain texture when one long exposure will smooth out details.  I just double the amount of multi exposures for each reduction of shutter speed. so 1 x 15 second exposure, 2 x 8 second exposures, 4 x 4 seconds exposures, 8 x 2 second, 16 x 1 second exposures and so forth.
Here are some examples of my multi shots:







always seems to work for me

 if you are worried about reciprocity, the total amount of light hitting the film should equal that of the exposure + reciprocity adjustment, so as you described, just work out your final exposure and divide up.

hope that helps - let us see the results?

I wrote a review of the Rollei 25 film in B&W photoraphy a while ago - I didnt like the film at all - very grainy with a resolution that was only just better than delta 100! And even hp5 looked brighter and sharper at quite high enlargements.  THe rollei 25 exposed at ei 25 developed quite well in id-11 1:1 given the same time as the old agfa apx 25.  I've not heard of a new ilford 50 film - do you mean Pan F?

[sparx]

Thanks Leon. You've confirmed my suspicions. I'm just a bit too cynical sometimes to think things really are that straight forward. 

I do mean the Ilford Pan F. I was under the (possibly mistaken) impression it was a revised emulsion which is why I said 'new'. Have you used it? What do you think?

[LT]

I've not ued Panf for about 3 year ... didnt know it haad changed.  it was quite nice when I used it before, had a sort fo creamy smooth feel to the tones - amazing resolution