Hi, the 1250 is a "stupid" LM983x based scanner which knows nothing about jpeg compression. The stop and go is a "feature" of the LM983x to avoid data loss (of course you encounter this problem...)
I think that the libusb and or the usb-stack itself is the problem. I've currently not testet here with 2.6 kernels. Another thing is the image size you scan. Tests showed, that scanning only small portions of a picture in 600dpi will work fine (of course - less data), while scanning larger portions will not work very well, but full-size scanning @300dpi should be no problem, at least with the plustek backend. Can you switch back to 2.4 kernel? Ciao, Gerhard On Friday 07 May 2004 16:11, m. allan noah wrote: > if this scanner is usb 1.1 and capable of jpeg compression in hardware, > that might explain the difference, since color scans at anything above 200 > dpi can usually fill the usb. windows might use the jpeg compression, and > sane might not. > > another possible cause might be usb packet timeouts. are there any error > messages in /var/log/messages? > > but i dont know much about epsons... > > allan > > On Fri, 7 May 2004, Prakash K. Cheemplavam wrote: > > Hi, > > > > I am using sane-backends 1.0.14 with epson 1250 scanner and have > > following problem: > > > > When I try to scan with higher dpi (eg 600, but starts at 240dpi > > already) the scanning process isn't done in one go. It is more like > > scan-pause-scan-pause-scan-pause...etc. Not only the speed suffers by > > this, but also the quality: Sometimes at the pause points i get > > horizontal coloured lines which don't belong there. (using xsane) > > > > I am using libusb 0.18 with 2.6.6-rc3-mm2 based kernel, but I tested an > > old 2.6.0-test11 kernel on other hardware, as well, here with libusb and > > scanner module and both at least show the "stop and go" symptom. (I > > haven't checked image quality. (Tested with scanimage) > > > > It seems xsane does more of that stop and goes than scanimage, but I > > haven't thoroughly tested it. > > > > > > As a check I tried to scan in windows and here there is no problem. The > > scan is done in one shot, so it is fast and the quality is great here - > > so it is not a hardware problem. > > > > > > SO I wonder what the problemin Linux is. I don't remember correctly > > whether I didn't have that problem with older sane-backends. Should I > > try older plustek drivers? How can I easily do it? > > > > Thanks, > > > > Prakash > > -- > "so don't tell us it can't be done, putting down what you don't know. > money isn't our god, integrity will free our souls" - Max Cavalera
