Digital BW, The Print

If you meter the gray object and the white is blown out - you will have 
a 127 difference.

There is no toe on digital (yet - I read Fuji is working on a new chip) 
it is linear - that is why highlights blow out so badly.


On Thursday, September 11, 2003, at 12:14  AM, Thomas Fors wrote:

> For example, say you have a scene with both a white and gray object in 
> it, and you meter the white object and placed it in zone 10 (paper 
> white) which corresponds to a digital value of 255.  You meter the 
> gray object at that exposure and it happens to fall exactly on zone 5, 
> so you make an exposure.   I doubt that the gray and white objects in 
> the digital file will have values of 128 and 255 respectively.  In 
> fact, no matter what values they fall on, I doubt that their 
> difference will be anywhere near 127.
>

If you meter the gray object and the white is blown out - you will have 
a 127 difference.

There is no toe on digital (yet - I read Fuji is working on a new chip) 
it is linear - that is why highlights blow out so badly.

>
>
> So, by using an ISO based on zone 5, objects that fall into zone 7 
> (where you would expect full texture) may in fact turn out to be a 
> value of 255 (paper white) in the digital file, and so will zone 8, 9, 
> ...

You are confusing zones and f stops again. While 1 stop steps work for 
B&W film, it does not for slide, colour neg or digital. You have to 
adapt to what you are using. Find out your latitude and remap. You may 
find on consumer cameras that zones are about 1/2 stop each. Some pro 
backs actually have a 12 stop latitude so again zones would have to be 
mapped.

I agree 100% about your exposure. Treat it like slide - meter for your 
important highlight (with detail) and let the rest fall where it may.


Regards,

Loring Palleske
Creative Imaging
416.301.1711