The concept of black and white film which could be developed by the standard C-41 processing anywhere, both by specializez industrial laboratories, minilabs or by particular persons with cetain levels of experience (the printing of copies on normal paper being also made) dates back to approximately two decades ago.
In 1980, Ilford (top worldwide specialist on black & white) launched its XP1 film, and soon after, Agfa introduced its Vario-XL emulsion (which would disappear some years later).
        

In the same way as its two only current competitors compatible with C-41 (the Ilford XP2 introduced in 1990 and the Konica VX400) the Kodak T-Max T400 CN is a ´chromogenic´ film, that´s to say, it uses clouds of colorants to make the image, instead of the silver halides of the conventional films in black and white.
        

Besides the easiness and convenience of the C-41 development for the negative and the RA-4 for colour paper in any photographic shop (something that doesn´t happen with the standard non C-41 black and white films), the chromogenic emulsions feature two important advantages:
        

First of all, unlike conventional black and white films, the slight overexposure renders a finer grain, because with it the clouds of colorants become more dense, being for example 200 ISO the ideal exposure index of the Kodak T-Max T400 CN (since a greater overexposure would diminish the sharpness), achieving a good acutance and a granularity comparable to a standard black & white ISO 100 T-Max film.
        

And secondly, in the same way as the negative colour films, it boasts a tremendous exposure latitude, so one can get high quality negatives to print on photographic paper and exposing at very different IE.
        

In fact, the Kodak T-Max T400 CN can be exposed between ISO 200 and 800 for the standard development, with ability for the uprated development (at a higher temperature or for more time) in one step (ISO 1600) or two steps (ISO 3200). Even, some subexposure tests have been made with worthy and decent results up to ISO 25, being probably the most usable photographic emulsion under all sorts of existing lighting conditions through all the history of photography, even beating the mythical slide Fuji RMS 100/1000 in exposure latitude.
        

Unlike the film Ilford XP2 (with a clear bias to the sepia tonality), the T400 CN obtains photos with an aspect approaching more to black and white, though at ISO 400 it has a relatively low contrast, getting betting results (with great richness of details and ease of printing) overexposing it at ISO 200 and positivating it on variable contrast papers, specially the Ilford Galerie Grade 3, processed in developer Universal PQ and the Ilford Multigrade IV with filter number 3,5, with developer tetenal NK2.

The T400 CN gives a smooth printing tonality, specially with the medium tones, which appear almost creamy.
        

The sharpness is very good, being a high speed film.
        

You can also obtain very good results making landscape photographies in sunny days, using green filters and positivating on Agfa Multicontrast Classic Grade 3 ½ Paper, achieving smooth tonalities and big enlargements due to its very fine grain.
        

The image quality and absence of grain are impressive for a 400 ISO film, equalling the best standard traditional ISO 100 Black and White films in terms of resolution and enlargement ability, though it doesn´t reach the superlative glamour and aesthetical image beauty of the best classical black & white based on silver halides.
The T400 CN is constituted by three layers incorporating in the same quantity the couplers for yellow, magenta and cyan, in such a way that a monochrome image sporting neutral densities is created.
        

Its huge versatility and preserving of the excellent very fine grain together with the good sharpness and remarkable global quality between ISO 200 and ISO 800, make it the suitable choice under conditions of difficult lighting, either because of low ambient light or due to the abundance of high contrast subjects.
        

With the conventional B & W films, when in a same spool there are frames made with subjects illuminated in very different ways, intensity and directions of light, the photographer always has the doubt if he has to develop ´soft´ or ´hard´ or looking for difficult intermediate solutions.
        

Facing it, with the chromogenic films like Kodak T-max T400 CN, almost 100% of the frames are enlargeable without any problems, only making the necessary adjustments, depending on if we are going to enlarge on traditional b & w paper or on color paper. And besides, with the latter, through suitable correction filters, we can attain virados with all the tonalities, enhancing sepia copies boasting a very beautiful ´old look´.

Compared to Ilford XP2 (specially designed for positivation on conventional black & white paper, with which are achieved better results than with the colour paper) and the Konica Monochrome VX400 featuring orange mask (created for its printing preferably on colour paper), the Kodak T-Max 400 CN, the one boasting finer grain, gets very good results with both types of photographic paper. This way, you can solve to a great extent the complexity to attain on color paper the most neutral possible tone, trying to approach as much as possible to an authentic black and white, something difficult because of the processing changes inherent to C-41, added to the fact that the exposure modifications between some frames and others can bring about chromatic changes in the copies.
        

To sum up, we can conclude that the Kodak T-Max 400 CN is a film offering great power of resolution and huge versatility, which along with its quickness makes it apt for different photographic tasks, including fashion reportages.