Film Scan Resolution
Find the scan DPI and source resolution needed for a large print from film.
About Film Scan Resolution
To print at a target DPI, the scan must deliver that many pixels per inch of print, which scales back to a scan DPI on the negative. Scanning at the right DPI captures the film's real detail for a chosen print without scanning too large or too small.
Formula
Film Scan Resolution
Scan DPI = print inches x print DPI / film width in inches
- source DPI
- Scan density needed to hit the print size
Worked example
With the default values below, Film Scan Resolution returns Scan DPI Needed of 4,233. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Film widthminimum 1
- 36
- Film heightminimum 1
- 24
- Print widthminimum 0.1
- 20
- Target print DPIminimum 1
- 300
Results
- Scan DPI Needed
- 4,233
- Source Pixels Wide
- 6,000
- Source Megapixels
- 24.00
Step by step
- 1Values used
- 2Film Scan Resolution
- 3Scan DPI Needed= 4,233
- 4Source Pixels Wide= 6,000
- 5Source Megapixels= 24.00
Assumptions and limits
- The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
How is Film Scan Resolution calculated?
Scan DPI = print inches x print DPI / film width in inches To print at a target DPI, the scan must deliver that many pixels per inch of print, which scales back to a scan DPI on the negative.
Why does Film Scan Resolution matter?
Scanning at the right DPI captures the film's real detail for a chosen print without scanning too large or too small.
What values do I need to enter?
This calculator takes 4 inputs: Film width, Film height, Print width, Target print DPI. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.