Ortho look with pan film?

2F/2F said:

I just found this on an astronomy Website: http://www.stellarjourney.com/images/spect2.gif

I appears that a #47 filter will give a pan film almost exactly the same look as Ilford Ortho, not counting grain and sharpness, of course.

Both filters seem to pass IR as well. Interesting...

Click to expand...

44A might be better.

My data on ortho film indicates a range of spectral sensitivity from roughly 400 to 560 nm wavelength with a peak about 540nm. The filters that seem to best approximate this are the #44 and #64, at least according to the data on the website link above.

What is missing from the bar-graph data is the percentage of transmitted light at any given wavelength. However, the filters noted above still seem the best choice.

Note that a blue filter like the #47, which has a cutoff above about 470-500nm, would better approximate a completely blue-sensitive emulsion. Ortho films are sensitive to the greens, which blue-sensitive emulsions are not.

I can attest from personal experience that the #44 filter does the job of rendering an ortho-look nicely. I've never used a #64, it may be a filter for more special applications like photomicrography.

Also, an 80B or 80A filter, even though it does not really transmit a spectrum similar to the sensitivity of ortho film, will darken reds and often gratifyingly lift shadows lit by blue skylight. This latter is one of the reasons many like the ortho look and use cyan filters. What the blue filters will not do is render green foliage much lighter than pan film, which is another of the reasons some like the ortho look.

Hope this helps.

Doremus Scudder
www.DoremusScudder.com

What size do you need? I've been through my stash of Wratten 4 inch filters and found number 44, 45, 47, 47B, 49, and 61 among many others. The 49 is deeper blue than the 47's. The 61 is the darker tri-color separation filter used with a 47 blue and 29 red. I also have a 29 if anyone's interested in doing tri-color seps or multi-exposure special effects. I have numbers 25 and 58 (with the 47B) making the full set of lighter color sep filters as well.

I haven't searched through the 2 inch filters yet.

PM if interested any any of these or if there are others you want such as IR, ND, or CC.