Filters for Colour Transparencies

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dave_whatever
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Re: Filters for Colour Transparencies

Post by dave_whatever » Fri Nov 04, 2011 7:23 pm Etc/GMT-1+01:00

Good point charles. You've explained why I still carry and use some or fewer of 81a, 81c and coral3 better than I did :P Of course this isn't the same as doing it in photoshop, although I can appreciate that for some people they would be able to colour balance to their satisfaction entirely in post.

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Re: Filters for Colour Transparencies

Post by IanG » Fri Nov 04, 2011 9:13 pm Etc/GMT-1+01:00

A factor that's being missed is how a film behaves with reciprocity failure, Velvia does worse than Astia and Kodak E6 films and has a tendency to quite marked colour shifts towards yellw/green even with exposures less than a minute, the later versions are better than the original.

So ironically corrective filtration taking the exposures into many minutes in tungsten light may actually make the final result worse.

Ian

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Re: Filters for Colour Transparencies

Post by dave_whatever » Fri Nov 04, 2011 9:25 pm Etc/GMT-1+01:00

I must say I'm no stranger to multi-minute exposures with velvia both old and new, in a landscape dawn/dusk context, and have never seen any noticeably adverse colour shift.

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Re: Filters for Colour Transparencies

Post by Joanna Carter » Fri Nov 04, 2011 9:33 pm Etc/GMT-1+01:00

IanG wrote:A factor that's being missed is how a film behaves with reciprocity failure, Velvia does worse than Astia and Kodak E6 films and has a tendency to quite marked colour shifts towards yellw/green even with exposures less than a minute, the later versions are better than the original.

So ironically corrective filtration taking the exposures into many minutes in tungsten light may actually make the final result worse.
The product info for Velvia 100 states that from 2mins, you should add a 2.5 Magenta and increase the exposure by 1/3 stop; after that, for each subsequent doubling of the exposure time, you need to add 1/6 stop of exposure but the colour correction can remain at 2.5M. Having made several long exposures, in low light, with Velvia 100, I can attest that it gives very good results, with the 2.5M filter not always being necessary as it really makes very little difference.

As to correction for tungsten, flourescent and even halogen lighting, I always rely on my Minolta colorimeter and, so far, have had predictable and consistent results. To my way of thinking, if you are serious about accurate colour photography, a colour meter can save a whole lot of film that could otherwise be wasted. Unfortunately, even the Kenko is quite expensive so decisions have to be made as to well you trust your own judgement on the level of filtration required to give the reult you envisage :)
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Re: Filters for Colour Transparencies

Post by IanG » Fri Nov 04, 2011 9:48 pm Etc/GMT-1+01:00

dave_whatever wrote:I must say I'm no stranger to multi-minute exposures with velvia both old and new, in a landscape dawn/dusk context, and have never seen any noticeably adverse colour shift.
The examples I've seen and shot myself were worse with tungsten lighting where there's less blue content to the light anyway, it may be that that exacerbates the colour shift. In daylight (dawn & dusk) with long exposures it's a more magenta shift but often not as prounced.

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Re: Filters for Colour Transparencies

Post by IanG » Fri Nov 04, 2011 10:08 pm Etc/GMT-1+01:00

Joanna Carter wrote:
IanG wrote:A factor that's being missed is how a film behaves with reciprocity failure, Velvia does worse than Astia and Kodak E6 films and has a tendency to quite marked colour shifts towards yellw/green even with exposures less than a minute, the later versions are better than the original.

So ironically corrective filtration taking the exposures into many minutes in tungsten light may actually make the final result worse.
The product info for Velvia 100 states that from 2mins, you should add a 2.5 Magenta and increase the exposure by 1/3 stop; after that, for each subsequent doubling of the exposure time, you need to add 1/6 stop of exposure but the colour correction can remain at 2.5M. Having made several long exposures, in low light, with Velvia 100, I can attest that it gives very good results, with the 2.5M filter not always being necessary as it really makes very little difference.

As to correction for tungsten, flourescent and even halogen lighting, I always rely on my Minolta colorimeter and, so far, have had predictable and consistent results. To my way of thinking, if you are serious about accurate colour photography, a colour meter can save a whole lot of film that could otherwise be wasted. Unfortunately, even the Kenko is quite expensive so decisions have to be made as to well you trust your own judgement on the level of filtration required to give the reult you envisage :)

The problem with product data and reciprocity is the data's not correct for all situations, there's to many variables, it's really down to experience, The shot you posted was an extreeme.

The other issue is that it depends on your expectations, if you switched to Velvia from a film that behaved quite differently then you may think it's worse at low light levels and long exposures.

This discussion opens a wider can of worms because you can see many long exposures dawn and dusk shot on Velvia with magenta casts, they seem almost the norm, but I've never had that problem when I was still shooting Velvia, and I never used a filter for long daylight exposures. Are they over doing the Fuji recommendations ?

Ian

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Re: Filters for Colour Transparencies

Post by Joanna Carter » Fri Nov 04, 2011 11:19 pm Etc/GMT-1+01:00

IanG wrote:This discussion opens a wider can of worms because you can see many long exposures dawn and dusk shot on Velvia with magenta casts, they seem almost the norm, but I've never had that problem when I was still shooting Velvia, and I never used a filter for long daylight exposures. Are they over doing the Fuji recommendations ?
As far as I can tell, the magenta casts to which you allude may well be more connected with Velvia 50; I have not yet found such with Velvia 100.

One detail from the Fuji data sheets, which a lot of people ignore, is the use of a very pale yellow UV filter when shooting in high UV situations. This can help with strong dominant colours on the coast or at high elevations.

The other thing that could be useful is for someone to do some tests as to how much filtration it takes to "nuke" the undesirable magenta.
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Re: Filters for Colour Transparencies

Post by IanG » Fri Nov 04, 2011 11:52 pm Etc/GMT-1+01:00

Joanna Carter wrote:
IanG wrote:This discussion opens a wider can of worms because you can see many long exposures dawn and dusk shot on Velvia with magenta casts, they seem almost the norm, but I've never had that problem when I was still shooting Velvia, and I never used a filter for long daylight exposures. Are they over doing the Fuji recommendations ?
As far as I can tell, the magenta casts to which you allude may well be more connected with Velvia 50; I have not yet found such with Velvia 100.

One detail from the Fuji data sheets, which a lot of people ignore, is the use of a very pale yellow UV filter when shooting in high UV situations. This can help with strong dominant colours on the coast or at high elevations.

The other thing that could be useful is for someone to do some tests as to how much filtration it takes to "nuke" the undesirable magenta.
it's always a case of keeping on top of the way films change.

I think one reason Fuji became predominat in the UK was consistency, even in the E3/4 days their Fujichrome was much more realistic than Kodak E3/4 films which were awful, I shot a lot of both, the Fuji nfilm was creeping towards K25. The release of 50D and 100D closed the gap with K25.

Early Velvia was like a film with the colour satuararion ramped up, the current product is closer to 50D & 100D.

The reality is that many here have been locked in to Readyloads, I useed the polaroid version which was 100D for many years, but in going down taht route you don't compare films and how theybehave.

I no longer shoot colour transparency films, the ones I used predominantly are long gone (specialist push process high speed E6) so that side of my photography has been digital for around 10 years, I will be shooting LF colour work but in future I'll shoot C41 because other than Ilfochrome (which I've bever really liked) there's no print material now.

Ian

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