A "real" TPU is just a lamp behind some ground glass (or translucent plastic), so there is not "projection" involved: The sensor scans the illuminat4ed negative or slide directly.
Have you checked out the link to the message from the guy who is using a lightbox on his Perfection 1200? He had some instructions about how to disable the 1200 TPU. The GT-8000 should be similar. ... and I can assure you there is no mechanism to turn the lamp off without a TPU (or a fake TPU) connected to the scanner. Karl Heinz On Friday, November 28, 2003, at 08:20 AM, Bart Buitinga wrote: > 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 <bartbuiti...@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 > > > > > > > > -- > sane-devel mailing list: sane-devel@lists.alioth.debian.org > http://lists.alioth.debian.org/mailman/listinfo/sane-devel > Unsubscribe: Send mail with subject "unsubscribe your_password" > to sane-devel-requ...@lists.alioth.debian.org
