Reciprocity for Multigrade RCIV paper [update]

Here is a reciprocity curve for Multigrapde RCIV Paper. The formula comes from f/295 forums : http://www.f295.org/Pinholeforum/forum/Blah.pl?m-1252335783/. The author (banana_legs ) uses this formula :
t_s = t_c + 0.0009 * (t_c ^2.2304)

I transcribed it for pinhole assist and you can download it with this link.

Thank to the contributor of the discussion here for their interest.

12/11/2012 : link updated

Working on improvements...

 I just found this thread on f295, with lots of feedback on the app.

I noted
-1/3 step ISO,
- apertures up to 1024
- extra reciprocity curves for multigrade RC IV paper (However, I disagree with the values given 15 minutes leads to 84 minutes corrected - I keep firmly on the fact that below 30 min, there is almost no reciprocity for MG RC IV - I will nevertheless include that curve)

I am also working on the following :
-  combos: storing presets;
- a real way of managing /adding/removing reciprocity curves.

So
- next minor updates may have extra ISO and apertures + reciprocity curve on the web sites
- next major : combo
- later : management of reciprocity curves

Version 1.7.2 is on the store

NEW FEATURES: 

• aperture list now starts from 1.4, and goes on with stand numbers : 2, 2.8, 4 etc., allowing for standard aperture and lens.
• Suitable for WET COLLODION : the aperture range together with sensitivity settings starting as low as 0.25 ISO allows for wet collodion usage

ENJOY ANY SLOW PROCESS : pinhole, wet-collodion.

BUG correction :
• optimal diametre now immediatly displayed when switching aperture modes between "predefined" and "computed"
• aperture properly restored when waking from sleep (used to set to "f:150" no matter was the "real" stored value
• selected tab restored when waking from sleep http://itunes.com/app/pinholeassist