Oh gosh, now you're trying to convince yourself that tofu burgers and ground sirloin taste the same? People who want TMY want TMY, not Delta with a lot of ketchup on it to hide the difference.
Oh gosh, now you're trying to convince yourself that tofu burgers and ground sirloin taste the same? People who want TMY want TMY, not Delta with a lot of ketchup on it to hide the difference.
Originally Posted by Drew Wiley
good point... and one vote for the sirloin ! (tofu may be toxic)
Anyway it would be interesting to make some side by side tests with "filter bracketing" and see how close can be the thing. I've the view that, in practice, main difference is spectral response... but this is for another thread !
You should buy a couple boxes and make those tests.
The curve shapes are radically different, not just the speed. Bracketing won't change that. If you want to do a test, compare TMX100 to Delta 100. They're both
T-grain medium speed, but again, with VERY different toe characteristics. Delta is a fine film in its own right, provided you're a vegan !
I think those tests can be done with some two 35mm rolls of each film. I would take a color check target, then make the shots with filters, this with tungsten and daylight, then referencing to standard gray in the target and let calibration software work to see corresponding shifts in the color triangle, this would spend one roll of each.
Second test would spend remaining two rolls with real subjects, faces, landscapes, fabric, fruits... with better matching filtration found.
A perfect match by filtration requires very professional resources, it would require developing an special new filter, this is using software to combine absortion bands from some 20 dyes to obtain a filtration that transforms the spectral sensitivity of one to the other.
It is possible that some wratten gelatin makes it match in the way than even an expert film user cannot see spectral response difference. That formal test would determine that.
Beyond what's spectral response... we'll, this is calibration. Ilford pfd shows curves until 1.8D, Kodak (I like kodak charts!) shows curves until 3.0D for advanced printers.
I think that toe is not that different, but there is a D100 very important (can be nasty) factor : reciprocity failure. Delta has much higher reciprocity failure that can act like benzotriazole toe cutter, the typical case is a 4 sec exposure (to smoothen water) in a river, then Z-IV can be sent to Z-III a ....and Z-III to zero. (shadows of the rocks)
3 years ago I made informal but extensive personal tests of Delta vs TMax vs Acros. I found that Spectral Response could be well matched (to my eye) with pale filters. Also I found that for long exposures Delta has the mentioned issue, and Acros was the best for that. Also I found TMax exceptional in resolving power and density buildup.
IMHO TMax range has too much blue sensitivity for what today can be considered natural look (faces, outdoors in special), but it's also vintage look. Anyway this is solved with mild yellow filtration.
So my personal conclussion is that I can obtain similar results with Delta for most situations, and TMax/Acros may be required with long exposures, at 2x the sheet price.
As until recently I was shooting rolls, and as Ilford vs Kodak rolls have similar price, I was using TMax.
Now I plan to shot mostly 5x7 and 8x10 and the price difference is too high for an amateur like me, so I'm thinking to adjust my process with Delta.
¿Why Kodak sells TMax rolls at the same price than Delta, and sheets at those expensive prices?
To continue the off topic discussion.
For my work, a straight line is a straight line, and I use 4x5 Delta 100 or 4x5 T-max 100 interchangeably, depending on what I can get. If one likes processing to a 'curve' then be shackled to the differences you find.
To continue the off topic discussion.
For my work, a straight line is a straight line, and I use 4x5 Delta 100 or 4x5 T-max 100 interchangeably, depending on what I can get. If one likes processing to a 'curve' then be shackled to the differences you find.
Quite straight !
I'd like to make you two questions. First is about the exposure time of this calibrabration, is this "in camera", or around 1s under enlarger ? How that would change if test was made with 8s?
Second question is about spectral response, do you need to use some filtration to get similar look when you interchange films? I'm specially interested in skin tonality...
This is Delta:
This is Kodak:
In the case of Kodak they say that the exposure for each wavelength is equal in Ergs, this is very well specified, but in the ilford case they don't tell, unfortunately (even they don't say if linear or log). Anyway the Kodak curve shows a clear step ramp from 500nm to UV,
my guess is that when combined with sunlight spectrum...
... it happens that blue renders lighter tones with TMax. So a mild blue or cyan filter should be used with Delta to get similar spectral response...
Thanks in advance,
Regards
PD: Sorry for the off
I endorse that and would expand the sentiment to "if you want to disparage the film compared to alternative emulsions, please do so in a separate thread."
Kevin, if you're keeping in touch with Keith on progress toward the minimum quantity, please update this thread periodically to share that status. Thanks in advance.
You are right, perhaps this should be moved to another thread, just the thing has gone a bit too off topic, anyway my intention was not at all to disparage the film by comparing it, just wanting to learn differences. What's for me the off topic posts can be moved away if disturbing.
At the risk of getting back on topic, Keith sent me an email indicating he has orders for 38 boxes. So if the price isn't too high from your perspective and the toe is OK.....you could order some?
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