Forum: Photography


Subject: What are the best DPI settings for scanning 4x6 photos?

jdw4jesus opened this issue on Aug 13, 2005 ยท 4 posts


jdw4jesus posted Sat, 13 August 2005 at 3:51 PM

I have a TON of 4x6's that I would love to scan and print out to at least 5x7's... I have a Mirotek ScanMaker 4900 with 4800x2400 DPI CCD, and 48 bit color So my questions are...How much DPI should I set my scanner at so I can get the best quality picture without a HUGE file (more than 20MB or so)...I know I can scan at the best resolution, but I cringe to think about how large the file would be :O I may want to edit the file later, and with a huge file, because my computer is so old and slow, it could be a problem. I do not want any "lines" in my photos as these are to be sold to art galleries, and they are picky, so that is why quality is CRUCIAL!!! Oh, one more thing, can anyone give me an estimate on file sizes for different DPI settings, so I can get a rough idea. Thank you very much!


3DGuy posted Sat, 13 August 2005 at 4:12 PM

5x7 @ 300dpi would constitute 1500x2100 pixels

so 1500/4=375
2100/6=350

So, to be on the safe side scan at 400DPI. That should be enough to print your pictures at a nice resolution. If you want to print go higher like 600DPI. You should be able to calculate the required res :) 400DPI would give you a file of 1600x2400. This gives a TIFF file of around 11MB

Message edited on: 08/13/2005 16:16

What is a friend? A single soul dwelling in two bodies. - Aristotle
-= Glass Eye Photography =- -= My Rendo Gallery =-


jdw4jesus posted Sat, 13 August 2005 at 4:36 PM

That is perfect! Now, I finally know the "formula" to figure that out! Thank you so much! One other thing... You said "400DPI would give you a file of 1600x2400. This gives a TIFF file of around 11MB"...my question is...how did you figure that out...what is the "formula"??? Honest, after this, I think I will pretty much all set! Thank you once again


3DGuy posted Sat, 13 August 2005 at 6:53 PM

400DPI.. (with DPI meaning Dots Per Inch) you got 4x6 inch neg. So 4400=1600, 6400=2400.

16002400 gives you 3840000 (digicam wise this would put you on 3.8 megapixels) pixels in your image. A 24 bit colour image means 3 bytes per pixel so 33840000=11520000 bytes which equates to 10,99MB. With some overhead for the TIFF format would give you around 11MB :)

Message edited on: 08/13/2005 18:54

What is a friend? A single soul dwelling in two bodies. - Aristotle
-= Glass Eye Photography =- -= My Rendo Gallery =-