Rollei Ortho 25 reciprocity correction

[tim_bradshaw1]

<p>Hi, I've recently bought some of this – which I presume is rebadged film from someone else in fact – and I've not managed to find anything useful on reciprocity-failure correction for it. As I'm using it in a 4x5 camera I'm pretty much committed to multi-second exposures unfortunately, but (also because 4x5) I don't want to waste too many exposures trying to guess the correction factors.</p>

<p>So, does anyone know anything useful about this? Thanks!</p>

[chris_waller]

<p>Tim, my rule of thumb for RF correction, based on the raw meter reading is:<br>

1-5 seconds - +0.5 stops, development 0.85<br>

6-10 seconds - +1 stops, development 0.67<br>

11-20 seconds - +1.5 stops, development 0.55<br>

21-40 seconds - +2 stops, development 0.45<br>

41-80 seconds - + 2.5 stops, development 0.40<br>

over 80 seconds - + 3 stops, development 0.35<br>

The development factor is based on the normal development time, e.g. if the normal development time were 12 minutes then at, say, +2 stops RFC, the adjusted dev time would be 5.4 minutes.</p>

[tim_bradshaw1]

<p>Chris: thanks! I'll use that if pushed: I'd like to find factors which don't alter dev time as I want to process a bunch (well, 4) negs in a tank rather than individually.</p>

<p>(That sounds like I'm being ungrateful: I'm not meaning to be – this is useful to know!)</p>

[chris_waller]

<p>Tim, hi. That's OK! :)</p>

<p>Here's an example of my RC table in operation. The exposure time was 30 seconds, based on a Zone III reading , with + 2 stops RF compensation and a development factor of 0.45 ( though please make allowances for my cheap scanner!). :)<br>

Film was FP4, rated at 50 and devved in Rodinal at 1/100 dilution, 20 C, 8 minutes.</p>

<div></div>

[Fotohuis RoVo]

<p>Rollei Ortho up from 2014 is Ortho 25 film from OrWo Filmotec production exclusivly for Rollei -Maco.<br>

Before August 2012 their Ortho film was coming from Efke/Fotokemika.</p>