RE: Why multiple exposure (was Re: (Gum) Tonal scale)

Hi Joe.

Stain: It's very subtle actually. Maybe the scanning process took care
of it ;) I can see subtle stain with my bare eyes (it could be that what
I'm seeing is usual for gum and I interpret it as staining - I mean
there was always a very pale greenish tint in the papers I tried to size
with clear gum dichromate).

Step wedge: Yes, on my step wedge every step is equivalent to 0.1 log
density units.

Pigment stok solution:
Schmincke "Cerulean blue tone" #481
15ml tube poured in a film canister, slowly added (a ready made) gum
arabic soln. (stirring vigorously) until the canister was full.

Emulsion mix:
Part A - Pigment - 1 part Pigment stock soln. + 2 parts plain gum arabic
soln.
Part B - Dichromate - 5% Ammonium Dichromate
Final mix - 1 part A + 1 part B

Paper:
Whatman HP watercolor paper.
(Actually it's a CP paper; pretty textured when compared to COT 320 -
especially when it gets wet.)

Drying time:
10 mins.

Exposure:
6 mins under BL fluorescent tubes.

Development:
1 hour in still water (automatic development), changing water every 10
mins.

-----Original Message-----
From: Joe Smigiel [mailto:jsmigiel@kvcc.edu]
Sent: 02 Aralık 2005 Cuma 00:27
To: alt-photo-process-l@sask.usask.ca
Subject: RE: Why multiple exposure (was Re: (Gum) Tonal scale)

Loris,

I'm not seeing any stain, pigment or otherwise on my monitor. It
appears that the upper steps have remained paper white.

If there were pigment stain, all steps would have a tinge of blue but
step 17 is the last step I see as having blue tint. Ditto as far as any
green dichromate stain showing.

I'm running a few tests myself with a Stouffer wedge today. On your
wedge are the steps equal to 0.10 density units? Can you relist the
pigment/gum/dichromate mixture and paper data you've used?
Received on Fri Dec 2 06:01:18 2005