How Do I Scan Newsprint Without Bleedthrough?
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From: Davy on 8 Jul 2006 22:17 Hi Jim. When ever I scan a newspaper I sometimes put a black card, or something black behind the page, about the only thing you can do I guess to stop 'print through' from the other side. Hope it helps. Davy
From: CSM1 on 8 Jul 2006 22:46 "Davy" <no(a)spam.invalid> wrote in message news:1HZrg.74734$LI3.35789(a)fe12.news.easynews.com... > Hi Jim. > When ever I scan a newspaper I sometimes put a black card, or > something black behind the page, about the only thing you can do I > guess to stop 'print through' from the other side. Hope it helps. > > Davy > You can scan using B&W and adjust the threshold level until the background print through disappears. Also you can adjust the contrast level after the scan in a Photo Editor. The idea is to adjust the white point until there is no print through showing. You clip the white end of the histogram. -- CSM1 http://www.carlmcmillan.com --
From: James McNangle on 9 Jul 2006 01:18 "CSM1" <nomoremail(a)nomail.com> wrote: >"Davy" <no(a)spam.invalid> wrote in message >news:1HZrg.74734$LI3.35789(a)fe12.news.easynews.com... >> Hi Jim. >> When ever I scan a newspaper I sometimes put a black card, or >> something black behind the page, about the only thing you can do I >> guess to stop 'print through' from the other side. Hope it helps. >You can scan using B&W and adjust the threshold level until the background >print through disappears. > >Also you can adjust the contrast level after the scan in a Photo Editor. >The idea is to adjust the white point until there is no print through >showing. > >You clip the white end of the histogram. I had a similar problem trying to scan some old letters my mother had written from France in 1918. They were written on poor quality paper, sometimes in pen, sometimes in ink, and sometimes in both, on both sides of the paper. A black backing does help, but even then with these letters, and often also with old newspaper advertisements, it is quite impossible to eliminate the bleed through by the method CSM1 suggests without also effectively eliminating the content. I did some experiments with scanning both sides of the document and then subtracting the scan of the back from that of the front. This is decidedly fiddly -- especially in getting the two sides to line up -- but it can give a significant improvement. I have written some technical notes on the subject which you can see at http://www.corybas.com/Technical/Experimental.htm. I have since seen how I think this process could be significantly improved, but I have not had time to test my ideas. James McNangle
From: Paul Heslop on 9 Jul 2006 05:23 James McNangle wrote: > > "CSM1" <nomoremail(a)nomail.com> wrote: > > >"Davy" <no(a)spam.invalid> wrote in message > >news:1HZrg.74734$LI3.35789(a)fe12.news.easynews.com... > >> Hi Jim. > >> When ever I scan a newspaper I sometimes put a black card, or > >> something black behind the page, about the only thing you can do I > >> guess to stop 'print through' from the other side. Hope it helps. > > >You can scan using B&W and adjust the threshold level until the background > >print through disappears. > > > >Also you can adjust the contrast level after the scan in a Photo Editor. > >The idea is to adjust the white point until there is no print through > >showing. > > > >You clip the white end of the histogram. > > I had a similar problem trying to scan some old letters my mother had written > from France in 1918. They were written on poor quality paper, sometimes in pen, > sometimes in ink, and sometimes in both, on both sides of the paper. A black > backing does help, but even then with these letters, and often also with old > newspaper advertisements, it is quite impossible to eliminate the bleed through > by the method CSM1 suggests without also effectively eliminating the content. > > I did some experiments with scanning both sides of the document and then > subtracting the scan of the back from that of the front. This is decidedly > fiddly -- especially in getting the two sides to line up -- but it can give a > significant improvement. I have written some technical notes on the subject > which you can see at http://www.corybas.com/Technical/Experimental.htm. > > I have since seen how I think this process could be significantly improved, but > I have not had time to test my ideas. > > James McNangle If I recall rightly Epson actually suggest the black paper behind the document trick. -- Paul (she dreams in color, she dreams in red) ------------------------------------------------------ Stop and Look http://www.geocities.com/dreamst8me/
From: tomm42 on 10 Jul 2006 09:58
Davy wrote: > Hi Jim. > When ever I scan a newspaper I sometimes put a black card, or > something black behind the page, about the only thing you can do I > guess to stop 'print through' from the other side. Hope it helps. > > Davy The black card is the best way to do this, black cheap construction paper works too. I have a file called "black" and just print a black page from the office laser printer. This works with book, too. Especially with new paper I feel that a grey scale setting works better than B&W which often drops text, when the drops are eliminated it is blocking up other portions. So I use grey scale and if I need pure B&W I'll set a black point on the text. Tom |