A few scanning tips

www.scantips.com

Help for Scanning Calculator

The calculator is hopefully self-explanatory, but here are some added details.

Basically, you specify image size (or scan size) and printing paper size, and it computes the answers to these questions:

  1. A specified existing image size (pixels) will print a specified print size (inches/mm) at what printing resolution?
  2. What scanning resolution is needed to scan a specified film or photo size, to print a specified print size at a specified printing resolution?
  3. Scanning a specified film or photo size at a specified scan resolution can print a specified print size at what printing resolution?

Plus it tries to show by clear example how the details work, and perhaps offer suggestions.

You select a  desired print size to be printed, in two steps: Specify the dimensions of the print paper, and also specify if you want short side or the long side of the image to exactly fit the paper size. And then select either an existing image or a new scanned image to print. In this latter case, also select EITHER a desired printing resolution to print it, or a desired scanning resolution, and then the calculator computes the other number.

Perhaps you want to scan 6x4 inches and print it in a document at 3x2 inches. Or maybe you want to scan 35 mm film and print A4 size (near 8x12 inches).

Or maybe you want to know the maximum capability of a 4000 dpi film scanner if scanning APS or 16 mm film.

Or if you already have an image of known size (pixels), the calculator shows the resulting printing resolution to give the selected print size.

Nonsense answers are not prohibited. For example, the calculator doesn't know that it is not practical to enlarge 8 mm film to print 11x14 inches at 300 dpi. It will dutifully compute that this requires 25,400 dpi scanning resolution. 😊 This is not practical, but you will know your capabilities.

Desired Output Print Size

This is the size of the print paper for the image you want to print, which is required for all calculations. Select the paper dimensions, and also specify if it is the SHORT dimension or the LONG dimension. This Short or Long dimension will be held fixed (won't vary), and the other dimension will float to fit the image shape. This is Short or Long side is the important paper dimension you want to be exactly filled (fitted to the paper). If the image is not cropped to match the shape of the paper, the other dimension will float, possibly to be smaller or larger than the paper, determined by their shapes (aspect ratio). If the image was previously cropped to be the same aspect ratio as the selected paper shape (so that BOTH short and long dimensions will fit the paper shape), then great, that's the idea. If not, it will advise what that crop size should have been, or that there will be some blank white paper space, depending on which dimension was fitted.

But the point is that the specified dimension (short or long) will be fixed (won't change), and if mismatched, the other dimension will float to come out whatever it must according to the shape of the Input size (shape of the scanned film or print size).

This method gives you more control to specify the desired print size — the same questions you must answer when actually printing on paper.

Printing assumes borderless prints, but you want say 1/4 inch margins, then subtract 1/2 inch from paper width and height.

Select the printed size above, which applies to any of the three options below.

Existing Image Size

If you already have an image of known size (pixels), for example digital camera images, this will calculate the printing resolution possible to print a given print size (which you specify at the top).

Selected Input Size, Film or Print

If you are scanning, this is the size of film or print or document that you are scanning. For example, if you are scanning 35 mm film, it is 36x24 mm in size. If you are scanning a 6x4 inch photo, this tells the calculator the size of it. There are many standard sizes offered, including older film sizes.

To Scan and then Print at xxx Resolution

This is the desired printing resolution, and it will compute the corresponding necessary scanning resolution (to print this print size from this input size). If you want to sufficient pixels to print the image at 300 dpi for example, this option will show the necessary scanning resolution that will do that. Generally you want to print photo images at 250 to 300 dpi.

To Scan at xxxx Resolution, and then Print

Given this specified scanning resolution, you can compute the possible printing resolution that will print this print size from the pixels created by this input size and this scan resolution.


Copyright © 2003-2024 by Wayne Fulton - All rights are reserved.

Previous Main