Scanner densitometer
Upload a scan of a step wedge, a negative, or a print, then click each patch from dark to light. The tool reads the pixel brightness and reports relative optical density — a real sensitometry check with no special hardware.
Density is relative to the brightest possible pixel (−log10 of brightness). It measures your own scan, so scanner settings affect absolute values — but the shape and range are what matter for judging exposure and contrast.
About this tool
This tool turns your scanner into a densitometer. Upload a scan of a step wedge, negative or print, then click each patch from dark to light, and it reads the pixel brightness to report relative optical density with Dmin, Dmax and range, a real sensitometry check with no special hardware.
How to use it
- Upload a scan of a step wedge, negative or print.
- Click each patch in order from darkest to lightest.
- Read the relative density listed for each point.
- Check the Dmin, Dmax and range to judge exposure and contrast.
FAQ
Are the density values absolute?
No, they are relative to the brightest pixel and depend on your scanner settings; the shape and range are what matter for judging a negative.
Do I need a real step wedge?
It works best with a step wedge for even steps, but you can also read any negative or print to compare shadow and highlight density.