Issue that starts at step 5 - Margins

[Rhea27]

I just got my 2nd camera (not using SDM yet because I don't have the switch and cables yet). Everything was fine in Scan Tailor until I got to "Margins", where every other page turned into a tiny little image...obviously the pages from the 2nd camera. I tried to attach an image on this post, but am not sure I know how to do that. Any advise on what might be causing this issue?

[Tulon]

Obviously your camera is putting wrong DPI values into the pictures. The DPIs going from cameras are *always* wrong, as cameras don't know the real size of objects they photograph. When you create a project, tick the "Fix DPIs even if they look normal" option. On the "Fix DPI" dialog you may need to work on the "All Pages" tab rather than on "Need fixing", as some of them apparently look normal to Scan Tailor.

[Rhea27]

Thanks Tulon. I have been unclear on how to estimate DPI on the types of things I'm scanning. I built my DIY scanner to scan old photos albums, scrapbooks, etc...so I am not scanning books with lines of text which can be measured for DPI. How is DPI measured for the types of things I'm scanning?

[Tulon]

You can scan a book page just to measure the DPI. It's going to persist until you change the zoom level of your cameras. Even better, scan a ruler, then measure how many pixels correspond to one inch. That would be your DPI.

[Rhea27]

Thank you. I think I've figured out how to determine DPI using Gimp. Which brings me to a new question...When I try to enter a value lower than 150 in Scan Tailor, the text is red and the APPLY and OK buttons are dimmed and unavailable. Is 150 the minimum that can be entered?

[Tulon]

Thank you. I think I've figured out how to determine DPI using Gimp. Which brings me to a new question...When I try to enter a value lower than 150 in Scan Tailor, the text is red and the APPLY and OK buttons are dimmed and unavailable. Is 150 the minimum that can be entered?

The idea is that a DPI lower than 150 is likely to be the DPI of your screen rather than your scan, probably inserted by some image editor / converter / etc. If that's not the case and your DPI is really less than that, it's considered to be of too low quality to get anything good out of it.
I suggest you post an example shot here - then I'll tell you for sure where the problem is and what can be done about it.