[filmscanners] RE: scanner dmax discussion

["Austin Franklin" <austin@darkroom.com>]

Hi David,

> OK. I missed that that was the assumption.

Sorry, I should have stated it!

> That appears to be the only problem here. Without that, it looked
> as though
> you were making a mistake I used to make. Sorry.

Well, hum.  Even if 8 bits wasn't enough, and it really needed 16, does the
density range actually increase?  Keep in mind, that every value is +- 1/2
the bit value.  So, the bottom and top number still CAN represent the lowest
value (as well as the top number), and therefore, the density range that is
"seen" can very well be identical.

For 3 bits, there are 8 steps, and for sake of simplicity, let's say over an
8V range:

0 represents 0 to 1V
1 represents 1V to 2V
2 represents 2V to 3V
3 represents 4V to 4V
4 represents 4V to 5V
5 represents 5V to 6V
6 represents 6V to 7V
7 represents 7V to 8V

So, in this case, you can clearly "detect" down to 0V and as high as 8V,
though obviously, without discernability from any other value in that
range...but you ARE able to measure those values.  Is your concern that the
discernability is decreased, and therefore you believe the density range is
as well?  But, as I believe this shows, the density range IS still
intact...no matter how many bits you use.

Now, technically, I understand that it really appears that you can't
guarantee the density range IS being measured, so that, in and of it self,
can certainly allow for the claim that the density range is "decreased" with
fewer bits...but as I believe this shows, it may in fact not be.  I am
missing something, or just not thinking clearly after uncrating and moving
around a 1600lb thermal chamber all afternoon?

Regards,

Austin

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