Hi Mark,
1. No. It's not about brightness. It's about color: it's about the limits a light sensitive color media has when representing a real color and its real transitions to that same color when it reaches its own shadows and highlights... That color representation on film requires a precise amount of light: a bit less light or a bit more light produce, ON NEGATIVE, different color shifts.
Real you say. Real is subjective in color photography. I know people who call Velvia's colors real, others that call Astia's real, others that call Reala the bomb, and people shooters that say Portra is the absolute best.
All these films provide different palettes of color, none of them are "real".
I do agree that when you are shooting for a very specific result, from a specific film, that will be processed a specific way, and printed on a specific paper; accurate exposure is very helpful.
The result may be what you call real, it is what I call placement and interpretation.
Forget the next steps: wet printing or scanning. Those are not discussed here... Use them as you prefer... This thread's about what happens to film. And if you don't have information on this subject, or believe the amount of light has no incidence in color or color temperature visible on neutral tones, you have the right to that opinion, but you're adding nothing to this thread.
Jaun,
Unless you are going to display the negative as the the final product, "forgetting the next steps" is silly, in fact it borders on ridiculous.
In fact you allude to that problem in this last paragraph when you talk about the "color temperature visible on neutral tones".
To make a positive image from a Portra negative we have to shine light through it, correct it's balance, not just for the scene (which is arbitrary) but for the orange base (which is affected by processing, age, heat, film batch), and invert it to some media where the paper adds a color bias too.
Papers have their own curves with shoulders and toes that affect how much of a the film's curve will be visible and the color balance. In a straight print (especially from a thick negative) much of the info on a negative falls outside the paper's range. Burning and dodging can bring much of that info into the papers range, but that process is arbitrary.
These requirements are variables, their application is arbitrary, not fixed by law or the limits in physics and the "color balance" isn't "visible" without applying the variables.
Making a positive is a required part of the process; if you want to see color balance in real life, you can't ignore the process of making the positive.
2. No. Not even filtering differently we get identical results.
I'm not saying that the photos will be exactly the same, I'm saying that the color balance doesn't move much and essentially equal colors are available in the print. The result is fully and absolutely dependent upon the printing process.
How we use the enlarger to place exposure on the paper to create our photo and how much we burn and dodge, is purely arbitrary, just as our color preferences are.
Reality is not what we get on paper, we get an interpretation.
3. Wrong. Magic in your imagination only: to me this is predictable and stable 100%, a science... This is just optics and chemistry... As C-41 is a standard, indeed it's careful exposure and filtering on camera PRECISELY what produces the best color once and again.
Cheers,
Juan
Sure C-41 (and RA-4) has a commercial standard; some labs are very good at that, some aren't. A perfect standard in practice it is not. Lab complaints here on APUG are ample proof of this.
Not only that, just as for B&W film, the process can be adjusted, with time and or temp, to suit the choices of the photographer's vision. With practice Push/Pull, Expand/Contract are very workable and used regularly with C-41.