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Digital Grain - Pixel Pain

How do you like spots, grain and scratches on your analogue film? I guess you just love them as much as I do. All the more it´s a shame we have to pixelize our beautiful detail loaded captures to show them off to the community online.

How do you like spots, grain and scratches on your analogue film? I guess you just love them as much as I do. All the more it´s a shame we have to pixelize our beautiful detail loaded captures to show them off to the community online.

You might have noticed that a pixel ain´t a dot, you know that dpi is not the same as ppi but have you understood what the real difference is? Talking about it with long time lomographers at the headquarters we noticed that we all knew there was a difference – we just couldn´t explain it properly.

PPI -stands for Pixels per Inch
DPI – stands for Dots per Inch

The difference is a quiet simple and yet sophisticated one. It´s all about how colors are being displayed, about the matrix of the medium. A pixel does not equal a dot. The main difference is that digital grids consist of pixels and printings of dots.

For printing you should make sure that the DPI is higher or at least equal to the PPI. If the DPI is lower the print will not fully display the high resolution of the photo. When printing a photo that has a lower PPI than DPI the printer will use more than one dot to represent a single pixel. Opposed to PPI, DPI is not relative to the page size.

Practically this means that a picture with 300 pixels on one side printed with 300 dpi will be one inch wide and resolution will be fine, suitable for most printing techniques.
If you print the same 300 pixel image with only 30 dpi you´ll receive a way larger but also coarse grained image.

Whenever you prepare or resize an image you need to keep in mind the medium for which you prepare your image. Whether you want to upload, archive or print your image you need to choose the right resolution already at the scanning process.

For inkjet printing 300 dpi will be a good choice.
For display on a monitor 72 dpi will be right.
For the SNAP! Magazine feature the local designer asked for images with at least 1400 pixels on one side and 350dpi.

Keep this in mind when you upload pictures for the SNAP! picture rumble. It would be a pitty if your great pictures wouldn´t be published because of too low resulution! It´s not many but we still receive some too small images.

Here we did what generally should´t be done. We scanned with 72 dpi, the picture has got 1800×1210 pixels afterwards we scaled it to 300 dpi. This would result in a large (63×42cm) but unclear image.

This Picture was scanned with 300 dpi, it has 1840×1232 pixels. This would result in a nice 10×15cm print.

written by somapic

6 comments

  1. kylethefrench

    kylethefrench

    so how the F do you make a scan "bigger"?

    almost 6 years ago · report as spam
  2. anarchy

    anarchy

    I guess I read the instructions too careful this time (Snap announcement):

    "at least 1400 pixels on one side OR 350dpi"

    So it should be 1400 pixels AND 350dpi, am I correct?

    almost 6 years ago · report as spam
  3. chuo104

    chuo104

    That was COOL! Thanks!!

    almost 6 years ago · report as spam
  4. dirklancer

    dirklancer

    thx 4 the tips!

    almost 6 years ago · report as spam
  5. somapic

    somapic

    @kylethefrench: the important thing is not to scan low resolution but good quality in the first place. don´t worry - a 35mm negative scan done with a non professional device will still be good enough for a small print but if you aim to blow up your negative to a supersize picture you will need to use a higher scan resolution (filmscanners usally scan with 4800ppi)
    @ anarchy: with 1400 pixels on one side and 350 dpi you are on the safe side! it would make some trouble for the printing if you used a 350 pixel image with 1400dpi ;-)

    almost 6 years ago · report as spam
  6. simonwright

    simonwright

    I recently got a roll of film crossprocessed and scanned at walmart. I sent a photo to be printed, a 4 by 6 scan, via iPhoto. I got back a 20 by 30 print and it looked great, I was really suprised by the results.

    almost 6 years ago · report as spam