elliotjnewman said:
no no, you have helped, but Im interested in when you said that the blacks will be blacker and the whites whiter - why? surely this all depends on the output of the image? and if the Pshop file looks less rich then just pump up the levels?
What is the difference in E6 and C41?
Crikey, you do ask a difficult simple question!!
Right - imagine how a computer thinks with an 8-bit RGB image: Red, Green and Blue are varying in intensity between 0 and 255. Black and White film is measuring only one linear scale - light intensity between dark and bright.
Green grass, just so happens to be 28% grey (which is half way between white and black), so does the back of a Japanese person's hand! Both these things are used by Fuji to calibrate their film. US calibration generally favours red, hence Kodak's film rep for producing red-intense images.
Let's say you're taking the sky, which happens to be perfectly intensely blue with no other colour whatsoever. B&W film in a camera will theoretically make that about 33% grey intensity, BUT actually more like 28% in real life as it is balanced on green grass, back of hand etc.
With computers, Red = 0, Green = 0, Blue = 255 for this example. This will give you a B&W image intensity which is R+G+B / 765 = 255/765... which is 33% grey.
Therefore, there is a 5% error margin because of manufacturer's calibration to "normal" photography.
This is a vastly over-simplified example, but there is a variation in the intensity, mainly because the computer's algorithm is "correct" and the film manufacturer's calibration is "optimised" to normal circumstances.
I invite everyone to shoot me down in flames for that, but that is what I was taught, and it seems to hold true.