Ektar100 Reciprocity Failure

[janaby]

Hello,
I'm starting shooting with ektar100 4"5" and I would like to find some table with the reciprocity failure thing for long exposure values (more than 30minutes).
Anyone knows anything about it?
Thank you

 

[tessar]

Found by way of Google, a handy chart:
http://dreuxsawyer.blogspot.ca/2011/12/reciprocity-failure.html
This page also has a handy link to the official Kodak technical data for Ektar 100.

 

[janaby]

Found by way of Google, a handy chart:
http://dreuxsawyer.blogspot.ca/2011/12/reciprocity-failure.html
This page also has a handy link to the official Kodak technical data for Ektar 100.

yes, i've seen that page also, thank you. and the technical data also...but it still doesnt answer my problem. i am going to be doing 1h30 exposures. well...trial and error right..

 

[Poisson Du Jour]

yes, i've seen that page also, thank you. and the technical data also...but it still doesnt answer my problem. i am going to be doing 1h30 exposures. well...trial and error right..

You don't have a problem. You have a challenge. And that challenge says, "expose some sheets!".
There is no alternative for good old fashioned experimentation as part of the trial and error process.
Suffice to say you will be looking at colour shifts and a gain in contrast with the majority of colour films showing reciprocity characteristics after only a few minutes. Published information, where it exists, can be far too subjective and vague. The experimental approach applies to all formats, not just 4x5.

 

[StoneNYC]

There's a reciprocity timer app that one of the film guys created, it only goes up to 30 minutes for Ektar (which I'm sure is Ektar100... he hasn't quite cleaned up the app so sometimes stuff isn't labeled exactly, but I do know he's starting with current films and moving backward to older films, so anyway... ) at 30 minutes, the timer goes to 3 hours 31 seconds... so if you're doing 1:30 hours... then your going to run into daylight issues where the light will change as the sun comes up... so that also becomes a factor (unless you're shooting in antarctica haha).

Anyway it's a paid app but really works well, I'll post an image (this is for iPhone).

 

[StoneNYC]

Images... These are all highly recommended apps for different reasons (film only guys might not use all of them but can come in handy).

Hope this helps.


~Stone | Sent w/ iPhone using Tapatalk

 

[DREW WILEY]

Color balance shifts are sometimes inherent to reciprocity effect; and you also have to factor in how different kinds of light sources might
create very different results on both counts. That's why Kodak is reluctant to publish long exposure recommendations, and why any generic
program might prove unreliable. One has to test for these things, or talk to someone who has done analogous work.

 

[StoneNYC]

Color balance shifts are sometimes inherent to reciprocity effect; and you also have to factor in how different kinds of light sources might
create very different results on both counts. That's why Kodak is reluctant to publish long exposure recommendations, and why any generic
program might prove unreliable. One has to test for these things, or talk to someone who has done analogous work.

Well some of us don't have the kind of money to blow on tests, what you spend in a week is what I spend in a year... Just saying...


~Stone | Sent w/ iPhone using Tapatalk

 

[Kevin Kehler]

That looks like a really great app Stone - for large format, I was recently shooting a 4-minute exposure and trying to figure out reciprocity times. I guess I need to top up my Apple account.

 

[DREW WILEY]

The fastest way I can think of to blow money is NOT to test in the first place. Kinda like saying you can't afford to send your kid to driving school, so you just buy him a new car every time it collides with a tree. If you can afford a silly smart phone you can afford a helluva lot of film.

 

[StoneNYC]

The fastest way I can think of to blow money is NOT to test in the first place. Kinda like saying you can't afford to send your kid to driving school, so you just buy him a new car every time it collides with a tree. If you can afford a silly smart phone you can afford a helluva lot of film.

Well my life requires me to have a smartphone or I wouldn't have any money because I wouldn't get work. However I only spent $50 on my iPhone. I know what you mean, but doing research to have a decent starting point (or having an app that gives you a good starting point) is very money saving.


~Stone | Sent w/ iPhone using Tapatalk

 

[StoneNYC]

That looks like a really great app Stone - for large format, I was recently shooting a 4-minute exposure and trying to figure out reciprocity times. I guess I need to top up my Apple account.

It is, it recalculates the time for bellows extension, which is pretty damn nice I would assume, I haven't used it for much as I haven't had the opportunity but the shots I already took in the 10-20 minute range look to be similar to the times given.

I know he takes the info from the data sheets provided by the manufacturer. That's all I know.


~Stone | Sent w/ iPhone using Tapatalk

 

[StoneNYC]

Personally I do not feel I need any of those apps. What I have been looking for is a Decisive Moment app. Then I won't have to think or anything. My head hurts when I do that.

That's called "program" mode on a digital camera hehe


~Stone | Sent w/ iPhone using Tapatalk

 

[RalphLambrecht]

SET UP A TEST PHOTOGRAPHING A GRAY CARD.and aim for the same density. this will make a nice graph and you can extrapolate to the desired times.

 

[Poisson Du Jour]

That's called "program" mode on a digital camera hehe


~Stone | Sent w/ iPhone using Tapatalk

The P on the cameras is for Professional. I have never seen a program that works...