From: Larry Roohr (lrryr@home.com)
Date: 07/04/01-11:57:25 AM Z
Joe,
I used your curve this morning and succesfully made a gum print of my
daughter, now I'm motivated, thanks for the kick in the pants! I dont think
you mentioned what you used but my piezo driver was set to the 'unsupported'
setting.
I used a clear enamel for a sealing spray on the cone inks, that can is
going to the paint shelf in the garage, it appears too thick. I've got a can
of that horrible smelling spray wedding photog's spray thier prints with,
I'll give that a shot next and see if I can find a can of your acrylic
stuff.
I converted your curve to % numbers. In case anyone else is interested:
input output
0 0
9 17
19 32
30 44
40 53
50 61
60 69
70 75
79 79
91 83
100 87
Thanks,
Larry
----- Original Message -----
From: <Smieglitz@aol.com>
To: <alt-photo-process-l@skyway.usask.ca>
Cc: <info@jacquesverschuren.nl>
Sent: Sunday, July 01, 2001 9:16 AM
Subject: digital gum negatives (was: Re: Shooting for Alternative Processes)
>
> In a message dated 07/01/2001 6:23:20, info@jacquesverschuren.nl wrote:
>
> <<So how do you get on with the 1160? Will it output A3+? Do you work on
paper
> negs? I can make an appointment at the Dutch Epson centre and bring my own
> media,>>
>
> Jacques,
>
> I don't think the Epson folks will suggest the following and I'm not sure
the
> Cone inks/software are available for your particular model printer. You
can
> check at www.inkjetmall.com for the info. I use Pictorico OHP
transparency
> material. I believe it is available in 13" wide rolls. Pictorico also
has a
> website which lists the available product specifications.
>
> The combination of the 1160 and Cone Piezography inkset/Photoshop export
> plug-in produces a very fine output and the "dot" is nearly invisible. At
> least to the degree where the gum printing process (i.e., watercolor paper
> texture, etc.) masks it.
>
> I also apply a curve to the output which produces a very flat negative and
> compresses the image data to print 6 steps of a Stauffer 21-step wedge
using
> my usual mix of Daniel Smith or Linel watercolor pigments and potassium
> dichromate gum emulsion. (Your mileage may vary.) Multiple layers are
> needed to build the print density, but I haven't noticed any posterization
in
> the images (2) I've made so far. This curve is still preliminary, but
seems
> to work fine. The only caveat is the inks on the printed transparency are
> very fragile, almost like a thin powder deposit. The Cone ink dries very
> quickly, but is easily removed through any abrasion. I've solved this
> problem by spraying the surface of the printed transparency with two light
> coats of Krylon Crystal Clear acrylic. I apply a fine mist from a
distance
> of about12", let it dry and repeat the application. This method imparts a
> very slight frosted texture to the negative (which does not show up in
> printing but perhaps diffuses the image slightly, again helping to mask
any
> dot) without causing the inks to run or bleed.
>
> If you are interested, I've uploaded a .jpg showing the curve in the PS
> dialog box and the result applied to an image file. The URL is:
>
> http://members.aol.com/kallitype/curve72.jpg
>
> The image originally was a carefully (and tediously) constructed grayscale
> digital step wedge with each square increasing by 1% and running from 0%
to
> 100% in value. The image shows the result of applying the curve to this
step
> wedge. The Input-->output levels of the curve are:
>
> 0-->35
> 26-->46
> 52-->56
> 76-->65
> 102-->85
> 128-->97
> 153-->118
> 179-->143
> 205-->172
> 229-->211
> 255-->255
>
> I've only used this system for a couple images, but it seems very
promising
> and I like the results much better than any of the other methods I've used
to
> create digital negatives. This is how I'm making the negatives at the
> present time. I've never done the stochastic imagesetter route or waxed
> paper negatives.
>
> Hope the information is helpful.
>
> Joe
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