The inverse square law, aka “butter gun,” can guide our darkroom exposure changes under an enlarger, but it fails with large or volumetric light sources used in alt photo processes.
The law stated for mnemonic ease:

An object twice as far from the light as another recieves one fourth the light.

Oddly, this principle of physics applies to more things than light, including sound, or in my fading memory, butter coating machines at the toast plant… or was that a Taoist plant?

this is meant as a caution to those of you considering a Canon 9500 printer. Skip it. I will not waste the web space, nor the amount of my time it would take to list the problems encountered in using this printer, the printer driver, the media failures… yikes, just thinking about it causes me more regret. Anyhow, I have nothing good to say about the Canon 9500 printer. I can not even say it looks good.