Juhana Sadeharju schrieb: > > Hello. Some Xsane/Sane-Epson notes: > > Summary: I want save the scanned image "as is" without effects > and without value range clippings at bottom or top. The design > of sane/xsane seems to make this difficult to optain. I need > help in finding suitable settings. > > I would like to have all Epson developers documentations? > Where I may download them? > > I suggest to read the rest of the mail paragraph by paragraph.
When you set gamma=1.0, brightness=0 and contrast=0 in the xsane main window then xsane does use a linear gamma table gamma[0]=0,... gamma[i]=i. The headers in the files created by xsane do not store the correct gamma values in all available version. This already is corrected for xsane-0.89. In most cases it does not make sense to do the image enhancement independent from scanning because - a lot of scanners do scan with e.g. 12 or 14 bits/sample but only can output 8 bits/sample. You get better results when you use the scanner internal gamma correction - even when the scanner can output more than 8 bits/sample you do not need more then 8 bits/sample in most cases. So doing a gamma correction and storing the image with 8 bits/sample reduces the file size and creates images with good results. If you think you need to do the conversion after scanning simply set gamma=1.0, brightness=0.0 and contrast=0.0 in the xsane main window and xsane does not touch the data. Best regards Oliver -- Homepage: http://www.rauch-domain.de sane-umax: http://www.rauch-domain.de/sane-umax xsane: http://www.xsane.org E-Mail: mailto:[email protected]
