Re: Opacity of digital negative substrates, was Re: Gum a la Sam Wang

Ed,

I would agree with Sandy's statement on Pictorico. If you test clear
Pictorico film along side a Stouffers, the clear Pictorico shows about half a stop
density with UV light.

Mark Nelson
In a message dated 11/23/03 10:10:35 AM, glassact@compuserve.com writes:

> Sandy:
>   If I remember correctly, the 361T densitometer in UV mode does not read
> deep into the UV, and misses the 360-380 nm range entirely.  UV is not UV,
> and the readings of some instruments have to be taken with a bit of silver
> salt. Best - Ed Stander
>
>From Sandy:

Chris,

As you know there are many substrates being used for digital
negatives but Pictorico is perhaps the most common. If you read a
plain piece of Pictorico with a densitometer in UV mode you will find
that it measures about log 0.15 or slightly higher. The UV reading of
most film substrates, by comparison, will read about log 0.05. In
other words Pictorico is less transparent to UV than film, not more.
Other substrates I have seen appear to be thinner and would probably
have less opacity.

Sandy
Received on Sun Nov 23 10:53:40 2003