Printing old photos in 8x6

[Airlane]

I want to send some old photos of varying sizes and shapes to be printed in 8"x 6" format but I'm struggling to make it work. I've scanned them at 600 dpi, cleaned them up using Photofiltre software, then pasted each one on a grey background of 8" x 6" in portrait or landscape, depending on the original photo's shape. However, to make them fit the background and thus be printable in the centre of the background without cropping, I have to reduce the size of most photos. When I send the resulting images to an online photo printer, many of them are rejected as the resolution has been reduced too much. The minimum required for an 8" x 6" print is 2400 x 1800 px.

I need to maximise the resolution and not crop the photos. How do I make this work?

 

[idcanyon]

I don't know Photofiltre so I can't give specifics but the concept you need to look for is resolution. An "inch" doesn't mean anything to the computer unless you also supply a conversion factor. When yo create your grey 8" x 6" background you need to look for a "dpi" or "ppi" option and set it to 300--that's your conversion factor. 300 is usually the correct number for printing. It sounds like your software is using a smaller number. 100 dpi is usually about right for screens. If you can't find the dpi or ppi option then look for a way to just specify the size as 2400 x 1800 pixels. Once you have the properly sized background canvas then you should get a correctly sized image when you paste it in. Good luck.

 

[snowbear]

DPI is absolutely meaningless to a web browser / screen, but it makes a big difference to the printer. Are you printing these yourself, or are you sending them out to be printed? If sending them out, what dpi does the print company want?

The printer I tend to use will take photos at 100 dpi or larger. Since print size (inches) = resolution (pixels) / dpi; for an 8x6 print at 100 dpi, I only need an image of 800 x 600 (8=800/100 and 6=600/100).

 

[idcanyon]

for an 8x6 print at 100 dpi, I only need an image of 800 x 600

100 dpi is a common minimum and that makes sense for poster prints which will be viewed at a distance. For little prints like 6x8 you really should be at the printer's maximum, which is usually 240 or 300.

DPI is absolutely meaningless to a web browser / screen, but it makes a big difference to the printer

The DPI value tagged in the file makes no difference to the printer either. The lab (or your printer driver) will scale your pixels to whatever size print you order, whether the file is tagged at 1 dpi or 10,000. DPI becomes just something you could measure after the fact, if you wanted.

DPI matters when you are trying to evaluate how an image will look at a particular size, whether that is screen or print. It is also useful when creating artwork to target a particular display/print size, such as the OP is doing here.