tonal range of b&w stocks: reversal vs neg.

chris hoag · August 3, 2009

Hi, in general which (if either) has a greater tonal range as in blacker blacks (d max?) and whiter whites (d min?) between reversal stocks of negative stocks? Thanks!

chris hoag · August 3, 2009

oops, that should say "reversal stocks OR negative stocks"

Chris Keth · August 3, 2009

I'm not really sure exactly what you are asking. Both stocks/processes are capable (when one knows what he is doing) of producing almost infinite gradations in between D-max and D-min. Both, when projected, can potentially have very inky blacks and the brightness of white is only limited by the base.

Are you asking about the contrast range of a scene as it would translate to each stock?

Brian Pritchard · August 3, 2009

In general negatives have a greater ability to record tonal range than reversal stocks; this is because reversal stocks are processed to a higher contrast than negatives. Reversal stocks are processed to a projection contrast. Having said that higher contrast stocks will give a denser black and usually a cleaner white.

Particularly in the case of black and white you have the ability to adjust the contrast of both the negative and the print whereas the final contrast of a reversal stock is determined by the first development contrast.

Brian

Dirk DeJonghe · August 3, 2009

This discussion is a bit pointless. What will be the final output of the film? A telecine cannot recover the deepest blacks you can get on high contrast reversal film. Even a scanner will be problematic. A low contrast negative can be printed on various positive stocks and the positive stocks can be processed to different gammas.

There are lots of decisions to be made here and it would be wise to consult both lab and postproduction people with experience in B&W.

Dominic Case · August 3, 2009

If you are asking which type of stock is capable of recording a wider range of scene brightnesses, then the anwwer is simple: negative does better. Printing or telecine transfer can then be used to select the range of tones required, but in general, the final screened result can't show everythinig that is on the negative. (That is the luxury - you get to choose in the grading/timing/colour correction session rather than on set.)

But if you are asking which type of stock has intrinsically whiter whites and blacker blacks, then the answer is reversal. Negative has a letter range of densities, starting from the grey base through to a modest maximum density. But you don't need more: it cptures the full range of tones in that scale, and it's not designed to be looked at. (In any case, its a negative!)

Finally, a print made from a negative can usually have a blacker d-max than a reversal original - but that depends at least partly on the processing, as print stock can be processed to a range of gammas.

chris hoag · August 5, 2009

Yeah I guess I was asking if the d-min and d-max were equal between the two types of stocks for example if you projected a totally black image (d-max) in both types of stocks side by side which would be darker? but this was helpful.

Dominic Case · August 5, 2009

Normally you wouldn't be projecting negative of course. But it sounds as though you are asking the question for some other reason - for example which is the best stock to run through a projector if you don't want light on the screen ????