What I like is seeing "experts" propound on how a particular curve shape = a particular image quality.
My question to them is "have you ever done side by side comparisons?". I have!
The quality of the image is Art! The quality of the image is also science. You need to understand both. It is clear that many have their own POVs to put forth! Right or wrong, there is a position that can be shown to be optimum. Until all of you investigate that point and make comparisons. ....... Well, you are just voicing opinions.
PE
PE, I absolutely don't disagree it's both art and science - but my disagreement here is that one material can magically just do it all by changing the developing agent.
I haven't designed films or analyzed their curve response from emulsion to emulsion - but I have done a decent amount of work/time within the analog audio realm and feel I have an intuitive understanding of how signals typically respond within it. Yes, sound is not light, but within the realm of analog - they're more similar than different.
Here's what my entire issue is: with ample exposure, on the input side, we're taking advantage of non-linearity of a given film to alter and change the
tone of what's recorded to said film by way of compression and saturation towards the end of the curve (let's just keep it shoulder here as it's simpler to perceive). Any curve other than a straight line (which of course Tmax isn't 100%) is going to compress or expand the input signal relative to what the signal (light in this case) actually was - highly based on the particular characteristics of the film used. e.g. After exposing something at EI 250 vs EI 400, or even EI 50, what's on the film is just plain different - before I've even put it into a tank of developer.
Now on the development side, just because we can use different developers to alter the resultant output curve (i.e. what exposed silver actually gets developed into visible silver), doesn't mean this is the same thing as non-linearity and compression on the input side - even if the developing agents have their own form of non-linearity. We can play games here and alter the "response" but the tonality has already been majorly altered in our original exposure. This doesn't discount the power of different developers by any means - but it doesn't mean they have the exact same type of compression effects as light->film.
Another example: within the realm of compression as it relates to
sound, one has a choice as to where in the signal chain they want to EQ a given signal to alter it's tonality. If you EQ pre-compression, you'll affect the response of the compressor, it's amount of compression, and the resultant output will not be a straightforward change. If you EQ post-compression you'll be EQing what's already been compressed and the response is usually more predictable - but operating on a different signal than what the compressor originally saw. One can do both if they like (and many do) - but they have different qualities altogether. It's not hard to make the light->film->developer connection here.
One of the big reasons I love film is due to this non-linearity and natural distortion that occurs based on how we want to (or not want to) expose something. I feel different characteristics of a given film used impart a different feel to different subjects/scenes and along with choice of developer and style - give a fair amount of latitude to the final product - based on the end-user.
Besides, even if we discount everything I typed above - we still haven't addressed the "grain" portion of things. Over and over when a manufacturer releases something they consider to be more "modern" or the "pinnacle of x technology" what they're really dialing in on a lot of times are the most visible lowest common denominators. Tmax is sharp, it has extremely fine grain. In the grand scheme of things, "Big deal." Maybe I was fine with the level of grain I already had. Maybe I like grain. Maybe I'd like to see a "modern" film with awesome tonality rather than "sharp! sharp! sharp!" Anyways, that wasn't what this discussion was originally about - but it's been constantly ignored in this thread. Even if you could get TMY to mimic the curve of TXP (and that's the best one can do, is mimic) it doesn't mean the affect on resolution and grain/texture are the same. Not everyone here is on a mission to remove grain from their photography.
If you want grainless flat-lines and zero distortion, I've got something here to sell you...
P.S.: DFC, I do value what you're throwing out there. I'm just conveying how I feel about things is all. When it comes to actually creating images and shooting film - I honestly don't even think about things at this level of analysis. I just push/pull, use different films/developers based on the results I've personally learned and experienced and what I've got work with.