Quote Originally Posted by DREW WILEY View Post
What th' .... Ice Racer? Mitutoyo makes the instruments that measure the dies and machinery that
make things like Peak in the first place. They're a precision instrument and optics mfg - and obviously
have to been of a far higher quality control standard than the thing itself being made. I don't know what you're thinking of. You can buy something as simple as a digital caliper from them (and they
make some of the very best) or some advanced instumentation that will measure in angstroms!

Peak 1 in conjunction with an enlarger will measure smaller distances than a consumer grade caliper.

In terms of focusing on the paper or the baseboard, I don't have an opinion on the matter, just the optical formula that predicts about a 2mm focus spread at f2.8 at 9x enlargement. This easily encompasses any photographic paper or film of which I am aware.

Modular transfer function focusing equation (equation #38 in http://www.largeformatphotography.in...DoFinDepth.pdf) :
N_max ~ 20 / (1 + m) sqrt(dv)

N-max = F number
m = magnification
dv = focusing leeway on the baseboard
20 = constant for circle of confusion about 0.15mm on the print