Tech question - Film - darkroom / in camera - HDR

(Not sure what to title this post, so I just put tag words.)

First off - HEY! been a while - hope every one is still shooting the fun stuff. See a new site was added to the G1 list of sites. Congrates RG!

I have a question for those very familair with Photography / darkroom techniques. Not sure which it will involve so... need those very familair with both that may be able to answer a question. (film)

My question pertains to HDR and film, I want to create a true HDR image. To do so i understand this can only be done and viewed currently with film.
So,
can someone explain the techniques (both in camera and darkroom) for raising the ratio to 30,000:1 or 20,000:1 to acheive a true HDR photo using film?

(HDR requires a 20,000:1 at it's lowest point and prefered ratio is 30,000:1 or better from what research i've done thus far - I can't find anything for film on this subject or how to raise the ratio high enough to acheive a HDR photo only on how to create the digital HDR simulation image.
- Digital doesn't have anything that can view a true HDR yet with the exception of one monitor - a $49k monitor - which isn't in production at this time as far as i know.
- on a postive note, i read, film can achieve a true hdr which can easily be viewed on a light box at this needed ratio but no explaination as how to go about it)

I looked into pre-exposure - using nd filters thus far - Sandwich the negatives and copy shoot?
thought of double exposure and pre-exposure to raise the dynamic ratio.

i'm a little lost on how to achieve this successfully with film, though it has to be pretty easy...?

I hope all are doing well and I could use the advice on the technique(s) - Hopefully there are still some left here at G1 familiar with the technique using film.

thanks

chase

[Mark_Oehler]

I can't say I know the answer, but you mentioned slides. My understanding is that, while color reversal film has a greater exposure latitude than digital, it pales next to Color Negative and doesn't come close to B&W Negative film.

If that is the case, wouldn't it be a property of the paper printed on?

Mark thanks for the reply - sorry about my other post i deleted it once i realized it was more me thinking out loud than a reply)

from my understanding if making a HDR on low contrast media - ie print, then print log unit would come into play. I'm not sure if that is the way i want to go - I think i'm going to go with a back lite transparency.

My thinking is if i can check off what i can do - then i can find a solution more easily for the rest to create a true HDR photo.

i've been reading and watching scienfic research videos on the subject of HDR and spectral span, Retinex, Lense and camera aberation issues etc over the past couple days since this post.

Here's one of the videos i watched conserning HDR including the semi famed 6 log unit HDR photo and Poloriod engineers testing of the claim and ability of creating such image.

PhotoTechEDU Day 32 - Art, Science and Reality of High Dynamic Range (HDR)


(The cathedral photo mentioned in the above video claimed 6 log units was challenged and it was shown that it could not be a 6 log unit Photo by engineers at Poloriod.)

I do have some questions my self on the test they did and findings in the above video - they should have added a single control camera and lense that could use both film and digital back IMO.

but this did give me something to shoot for - a 6 log unit HDR photo.

As far as latitude - there have been arguments / debates on the latitude of negative versus current E-6 slide going on on another site by those that know much much more than i on the subject and specific film curves - perhaps even here. I've read a couple of these threads. and they're proposed soltions for a better slide.

I'm not so sure i agree with they're line of thought given standard pro negative films.

However - if using ultra high def B&W negative film and color filters - i would agree this may be the way to go to increase my dynamic range of the final transparency.

I have a lot more to read on the subject, but i'm not sure at this point if latitude would be the real issue for creating a true HDR, not if layering is the technique used to create it that is.

if i use layering as the technique - I may have come up with a somewhat simple solution that should work for creating the 6 log unit HDR. It should anyway.

As stated, i have a lot more to look at and find the solutions for the problem areas for first.

I have however, found solutions for most all of the issues mentioned in the above video. taking into account their calculations - i should be able to acheive a 6 log unit transparency rather easily all things considered.

it's worth a try anyway.