Re: Inkjet negatives and Van Dyke Brownprints

Sandy et. al.,

I've posted a comparison jpeg of my final VDB prints from the test
negatives I've been working on the past few days. The URL is:

http://my.net-link.net/~jsmigiel/images/technical/VDB_test_prints.jpg

(Same disclaimer as yesterday: a nude image and fairly large file...)

The image compares a VDB made with Sandy King's neutral VDB curve at
left, a central original digital file, and at right the final VDB print
made with my adjustment to the highlight area of Sandy's curve. That
curve is shown in yesteray's posted image at:

http://my.net-link.net/~jsmigiel/images/technical/vdb_test_11-19-04.jpg

Thanks again to all who contributed to this thread and especially to
Sandy King and Mark Nelson who steered me the right way by relating some
of their personal experiences with the digital negative method.

If anyone is interested, I've summarized the process I went through
below.

Joe

For the digital negative
1) RGB digital camera file transferred into Photoshop where the file was
desaturated and manipulated using Channel Mixer. (I created a
pseudo-orthochromatic response.)
2) The file was inverted to a negative image and digital stepwedges and
opaque image borders added.
3) The VDB adjustment curve was applied to the negative image file. (I
excluded one of the four digital stepwedges from the curve application.)
4) The desaturated RGB file was printed onto Pictorico OHP transparency
material using the Epson 2200 and photo black ink set. Color setting
set to color inks. Media setting was Premium Glossy Photo Paper.
Printed at 2880 dpi with high speed setting disabled.

Emulsion
1) Standard Van Dyke Brownprint solution coated in normal fluorescent
room light onto Cranes' Kid Finish using a glass coating rod. (I prefer
Cranes' PS8116 paper ecruwhite. However, one print in the example was
printed on Cranes' AS 8111 white.)
2) Coated paper dried in the dark using a hair dryer with cool air only
for about 10 minutes.
3) After drying, a second emulsion coat was added and the paper dried
again in the dark.

Exposure
1) NuArc 26-1K mercury plateburner set to 350 units.
2) Stouffer 21-step wedge(s) added above the transparency material to
monitor exposure.
3) Exposed visually to step 16. Step 2 is bronzed with this exposure.
(The final print will gain an additional 2 steps following processing
and drydown.)

Processing
1) Print immersed with constant agitation in 2% citric acid bath for 3
minutes under normal room light.
2) Two successive baths of plain 2% sodium thiosulphate ("hypo") for 1
1/2 minute each.
3) Print rinsed in running water for 1 minute.
4) Print immersed in Kodak Hypo Clearing Agent for 3 minutes with
agitation.
5) Print washed for 5 minutes.
6) Print immersed in Clerc's Thiourea-Gold toner for 2-5 minutes (until
desired color is reached by visual inspection).
7) Print washed for 15 minutes in running water using a tray siphon.
8) Print air-dryed on screens (emulsion-up).
9) Print flattened in drymount press using low heat.
Received on Sat Nov 20 16:26:40 2004