[sane-devel] Epson gt-8000 transparency experiment

[Bart Buitinga]

Hello again,

It's going to be some retro demonstration if this goes to work. Thanks
for all your replies.

After some fiddling with the configuration files I found the number that
defines "Blindfarbe" (shines just one of the three monochrome tubes in
the gt-8000's sensor) for BW modes can be set 0 for none or 1, 2, 3 for
R, G, an B. Unfortunately -1 an 4 both default to none. If there's no
known way to override the hardware detection I think I'll just add a
switch in the internal power cable to the tubes to get them off, also
because the autodetection of accessories, as it differs between the
document feeder and the TPU is beyond just shortcircuiting and of course
I wouldn't want to risk this splendid device that the previous owner
must have thrown away after obtaining a new pc with ECP or similar.

I've been trying some combinations without a projection screen, but I
think the sensor would demand a strictly parallel bundle for that to
work. (That is of course possible, but would take a lens the size of the
print.)
Just hoovering the enlarger over the scanner only results in a light
spot at the position of the enlargers lens

Considering the amount of light: I think a projector would be overdone
if theres no need to overpower the scanner tube or false light. These
old enlargers have relatively strong lamps because in the pre-multigrade
days high grade photo paper was not too sensitive.
But if the Opemus lets down, I also have a Krokus 3 with a condensor
extension that throws all the 100 watt light through a 35 mm window
instead of its usual 6x9 cm, about 3 times more powerful
(And also: It would then help to scan on less than a4 format... Also it
has the same lens entrance as my Praktica, so it may be easy to use it
with a large diameter telelens to get an up to 60 mm wide parallel
bundle... Well allright, I know what I'll do this afternoon)

But if someone around actually has a TPU, I would be very interested
what kind of projection (screen or parallel) it uses.

Bart Buitinga

Martin Collins wrote:

 > On Thu, 27 Nov 2003 21:02:43 +0100
 > Bart Buitinga <bartbuitinga at xs4all.nl> wrote:
 >
 >
 >>It occurred to me that if it is possible to project a negative on
 >>the scanners glass pane using a slide accessory, it might also work
 >>to use a photo magnifier (I mean the thing used to print in a (B&W)
 >>darkroom, an Opemus 11 to be precise)
 >>
 >
 > An enlarger. You might also use a projector.
 >
 >
 >>with some kind of half transparent projection surface,
 >>
 >
 > It might work better without a screen, just project the image straight
 > into the sensor.
 >
 >
 >>just if I would succeed in scanning with the lights off.
 >>
 >
 > Right, you would need to turn the lamp off. Although, if you didn't
 > use a screen the lamps may not matter.
 >
 >
 >>I guess that normally the scanner would notice a device connected to
 >>the 15 pin entrance on the rear, and maybe it would just be a matter
 >>of shortcircuiting some of its contacts, but maybe there is a trick
 >>to do it with one of the ini's that twain32 (win95) uses. (In the
 >>latter case I hope there's a similar linux option or continue my
 >>quest elsewhere)
 >>
 >
 > I don't know if the sane epson backend can directly control the lamp,
 > I know the mustek one cannot. So you need to fake the scanner into
 > thinking it has a transparency adapter connected. That 15 pin
 > connector probably has 24V on some of its pins so don't go shorting
 > any of them unless you know what they connect to. If you don't have a
 > TPA so can't sniff its protocol you could open up your scanner and
 > disconnect the lamps.
 >
 > I would try it with the lamps on and no screen first, see what you
 > get. Please tell us the results of your experiments.
 >
 > Martin
 >
 >