RE: For those who are interested in making digital negatives using pigmented inksets

Loris wrote:

>
>All I can say is that; the UV blocking ability of my negatives should be
>quite high as I print Van Dykes with clean highlights and open - not
>murky - shadows around 8 - 10 mins. under 10 x 40 Watts 24" Philips
>Actinic 05 (equivalent to BL in terms of spectrum) tubes - with electric
>ballast - placed exactly 3" above my contact print frame's glass (it's a
>standard 8x10" B&S frame). Tubes are as close as 1/8" to each other. I
>think 8 - 10 mins. is a considerable exposure - comparing Sandy's 5
>mins. exposure test with half the power 20 Watts Sylvania BL tubes which
>showed 17 steps (see
>http://unblinkingeye.com/Articles/Light/L2/l2.html), this makes around 2
>stops exposure difference.
>

Loris,

If you are getting good clean highlights and good open shadows then
your negatives are obviously right for VDB.

However, 8-10 minute exposures seem incredibly long to me for digital
negatives, considering your set-up, i.e. high output tubes used at 3"
from the printing frame with close spacing. My set-up for the tests
described in my article on UV light sources was normal output bulbs
used at about 4" from the printing frame. Also, as you can see from
the tests the first maximum black is at about Step 3 or Step 4,
indicating that the tests received about 1.5 to 2.0 stops more than
needed. And these results pretty much agree with my current work
conditions as typical exposures for VDB and kallitype with my bank of
BLB tubes is in the 2-3 minute range for digital negatives with a UV
printing density of about 1.8 (from about 0.20 to 2.00).

Sandy
Received on Fri Jan 2 12:54:28 2004