By any chance do you know what would be a good filter to make the ortho film look like early blue sensitive only emulsions?
Sorry, it took me a while, but I've finally processed the Ilford Ortho sheets, so that I can update this thread and show you the results.
I did a 3 minutes pre wash and then I developed them in Rollei Low Contrast 1+4 (300ml of solution) using the Jobo CPE-2 and continuos agitation at 20 °C for 9 and a half minutes
The films were exposed at 50 iso.
These look great!
I personally do not mourn the loss of orthochromatic film having had to use it for many years. With the advent of panchromatic film gone are the featureless skies and exaggerated skin blemishes. Good riddance. Orthochromatic film has very little to recommend its use.
I'm not sure how much the Rollei/Maco/Adox stuff represents a typical pictorial-ortho film, but it has the virtues of really fine grain, really high dynamic range, and interestingly high but still pictorial contrast.
Rollei are wonderfully inconsistent in their descriptions, but it seems that their film is sensitive up to 610 nm (I can't find the shape of the curve). Whether you consider that "true" ortho is down to your definition of the term, I suppose, but to my eye 610 nm is orange. I think the late lamented "orthopanchromatic" Efke 25 reached up to 650 nm.
It is just as easy to find a pan film you like and then put the right filter over the lens!
To make everything clear.
orthochromatic film sensitivity 375 to 560 nm
isochromatic film range extended to 620 - 650 nm
panchromatic film range extended to 660 - 730 nm
Sorry to be negative about ortho films but I have been going thru some of my older photos and find that they are not as good as they could have been if a better panchromatic film had been used. Of course my choices were limited at the time. On doing further research and looking at the films I used my comment about "featureless skies" may have been caused by the sensitivity of early panchromatic films. Early panchromatic films were overly sensitive to blue light and therefor did not represent colors in the correct shades of gray.