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As usual, 138s, you have so little experience with certain actual products that you're speculating about how much of a curve is actually usable
Why would you test for such gross overexposures?Bellow you may learn what Ektar exactly does, of course the +6 overexposure test image has color shifts (that can be corrected), but in an average metered +6 overexposure you may have areas at +9...
For urban legends saying that "it cannot be overexposed" that +4 overexposure result is quite disturbing
My view is that graphs in kodak datasheets are totally exact, densities mostly linear in 10 stops and some creative color shifts for +5 and +6 overexposure. Not that weird that you have some shift at +6.
First, he picks a lens with serious falloff,
just a lot of hurried garbage-in/garbage-out BS.
Why would you test for such gross overexposures?
I'm not being rude. It is what it is - a worthless shoot-from-the-hip pseudo-test. My argument is that I know what real tests actually consist of, and that isn't even remotely one of them.
Adrian, yes, deep shadows under a blue sky are blue, just like the Impressions discovered. But with Ektar, that blue gets inflected with an annoying cyan cast, whereas in chrome films it is not, even when exaggerated, and in traditional portrait CN films it is artificially warmed. The problem was way worse with the prior Ektar 25. Of course, since you're working with other people's shots you have the challenge of salvage printing quite a bit of the time, no doubt. But I'm speaking of optimization by having every step under personal control. Digital workflow can't recover anything that darkroom options can't. Curve reconfiguration was done for decades prior to scanners; it was just a big expensive headache potentially involving quite a bit of film and print dye tweaking. But sometimes it can be done fairly simply. PS just mimics these functions, often right down to the names for the operations. Then there are all kinds of squirrelly gamut limitation of inkjet inks, which one simply has to make the most of, just like with any other color photographic medium. I tried to become a watercolorist as a kid, which offers tremendous hue control, but just never had the right disposition to be a painter. More of a hiker for whom a camera is a much better fit.
often times, actually looks better than than you’d think it would, given how it was exposed.
I guess I am just not as sophisticated as you are.Frank, do I have to explain you that? Really? Suposedly you had to be aware...
Me, I don't understand why the same emulsion has to be sold at 200% or 300% price if coated on sheet instead rolls, when manufacturing sheets it's cheaper than rolls.
Sure ilford doesn't loss money when selling BW sheets at similar price than rolls, so when kodak sells BW of color sheets at that insane 200-300 overprice (specially in the EU) I feel that they practice destruction of LF.
PE (Ron Mowrey) used to make the point that some emulsions had to be reformulated to coat successfully on different bases.
IMO the single thing that may have to be changed from rolls to sheets is the undercoating layer that may have to be specific to adhere well to the kind of base plastic. But this is of low technical or economic impact and Estar can be pre-treated to take the same kind of liquids (lipo or hydrophilic) than acetate.
For the rest, manufacturers give the same sensitometric/spectral curves for rolls than for sheets, making no distinction so it has to be much the same.
Some people have been saying that emulsions are different because Kodak gives different development times, but this is related to the typical agitation in specific tanks, Kodak gives the same times for rolls and sheets when agitation is the same like in the "Rotary-Tube Processing—Rolls and Sheets" section.
It would be totally crazy to develop a complex emulsion like Ektar or Portra specifically for sheets as sales are that low, IMO sheets are a subproduct from rolls business, they simply coat some master rolls with a different base and perhaps using a different undercoating... if not it would not be viable.
Today the single known emulsion (I recall) it's specifically made for sheets it's TXP, which probably it is a bare derivative from TX, perhaps simply having different amounts of component emulsions mixed, anyway TXP was not invented for sheets alone but for 220 rolls (half of Salgado's Genesis was shot with it).
this can be addressed in post, specially easy in hybrid. NC and VC did not make sense in the digital minilabs era and they did the same easily with soft. What is critical is spectral response, converting spetral information to 3 colors is a loss of infomation, what you loss in that step is lost.
Ektar : No way you get 7 stops linearity if you expect clean dye curve independence; crossover will set in one extreme, shouldering the other. I'd say realistically, no more than one stop either side of what you'd normally expect from a mid-contrast chrome film like Provia or E100.
Nope. They have to match the sensitometric behaviour between formats because consumers will complain if they didn't
OK then. Show us
OK then. Show us how you'll do this. I'd like to see you convert 160VC into NC.
I've never seen a sensitometric difference rolls vs sheets with fresh film, at least with films I calibrated.
Across all internet you won't find a single technical document (even no graph) showing sensitometric or RMSG differences of same modern emulsion in different formats, I challenge you to find it.
Also you won't find any technical reference (Shanebrook, etc) reporting any modification in the emulsion for LF vs rolls, or reporting any difficulty in curtain coating the LF base.
You will find nothing because commonality (when possible) is common sense, and making small batches specific for LF is not about common sense at all.
My point was that two Porta flavors were less a need as vast majority of C-41 film is scanned and by common digital processing the image can be controlled beyond the different nuances the two flavors had.
Anyway, if you want a NC vs VC matching then you can get it perfect.
The most technically perfect way would be a 3D LUT matching colors in the negatives before color conversion. Scans should be made in reference conditions. ie taking 16bit/c all DR in the scanner with all adaptive enhacements disabled.
As Spectral Sensitivity and Sensitometry are exactly matching then difference has to be in the final dyes. So advanced colorimetric Math says that a Perfect match can be obtained with a 3D LUT and that it's a kid's game, if mastering 3D LUT colorimetry.
From that evidence, just applying a bare 3D LUT to the raw scan you would have a totally matching emulation, not mattering the scene kind or illumination source in the particular frames.
To me it was interesting to learn that Spectrums/Sensi. were the same in NC vs VC, and that simple difference was only in final dyes.
"Characteristic curves" in the datasheets show an slightly different contrast that it has to come from the final dyes (rather from halides and filtration) because spectral sensitivity is matching. This allows a perfect matching with a simplistic technical approach.
If spectral sensitivity was different (it isn't) a general perfect match could not be obtained, because depending on illumination and on subject spectral reflectance a different 3D LUT would be required for each particular situation.
but all the evidence points to every m2 costing more to coat than tri-acetate and requiring alterations to the coating formulae to ensure identical performance to tri-acetate.
You quite evidently haven't done the work before making a loudly confident proclamation on the basis of nil experience. If you had, you'd realise it's not as simple as you think
fact that directly contradict comments from the late Ron Mowrey, [Former Kodak chemical engineer with his name on a wide range of industry patents.] But, we should totally take your word that all these things are super easy and barely an inconvenience?
Ron Mowrey
Don't tell me that's adjusting water content in the gelatins to adjust viscosity for a certain coating machine...
We get it already, man. You think it's too expensive. Do you know you've replied to this thread an incredible 73 times? Have you made your point yet or do you need another hundred posts to make absolutely certain your opinion is hammered home? This is an interesting thread to me but your over-posting and arguing with people sucks the oxygen out of the room. I don't have anyone on an "ignore" list but damn man, can you please consider giving it a rest?
This is true, but 90% I'm only answering to direct interpelations, check it.
My over-posting is due I'm defending alone a minoritary position facing several posters, one of them very agressive going easy to personal disacreditation, rather answering in the same way I try to bring technical facts, which contributes to that over-posting in this case.
Film price has always been a heated debate because some have commercial interests.
If you explore my positions you may find that debate is also technically enriched.
...anyway rather complaining, tell what are those LF emulsion modifications that some say it explains kodak sheet overprice, because nobody showed one...
Also you are free to ignore what you want, of course, I don't feel offended.
The single thing you may have to change it's the subbing layer, because it has to adhere well to the particular plastic of the base, beyond that... what do you have to change to coat for sheets ? Any remotely feassible guess ?
Have you ever worked in a factory setting, that produced anything?
Do you have experience in establishing quality control for something even as basic as a box-folder?
Production scale chemistry is not 'mix a gallon and we'll correct the next gallon if there is an issue' kind of thing, and what works for a gallon jug....
The reason that you are defending the minority opinion is that you are just wrong.
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