The thing that was part of the misunderstanding that green is a mix of blue?
The thing we had already put straight?
Only to have you reposit the entire misunderstanding again?
I see...
It is directed towards the comments about colors and pigments.
PE
A blue filter will do. It's not about being the complementary colour in a colour wheel, but about excluding that part of the spectrum ortho film is insensitive to.
This thread WAS about ortho film. Some had suggested filtration to render an 'ortho look' with pan film.
Subtractive?
Yes.
Apply filter(s) that are a minus type. When you filter for B/W you are not adding colour but subtracting (neutralizing/removing to whatever degree) the colour. A minus yellow (blue), minus magenta (green) or Minus red filter (cyan) or the combination of these would tend to get you close to ortho on a pan film.
That is why I first suggested a blue filter. Jnanian said he liked the "look" of ortho emulsions. By this I assumed he meant the typicall rendering of values we associate with prints by the old ortho glass plate landscape photographers - ie open, luminous shadows, white skies, atmoshperic haze etc. One can come pretty close by using blue filters with Panchromatic film.
i might try my best to get over my aversion to filters .. dark blue ?
and with the others, should it be the dark filters or the light ones ?
That is why I first suggested a blue filter. Jnanian said he liked the "look" of ortho emulsions.
Blue filter on pan film naturally passes only blue
Not really. These high pass filters have a rather soft transition as opposed to low pass filters (IR, red, orange, yellow). So there is some green and even red passing though.
See curve "Blau 38":
Well yes, the filter you show is not "blue", but more likely "light cyan-blue". It is probably meant for coloring tungsten light sources to give an impression of "blue" compared to unfiltered light. The reason why it passes so much green and even red is to increase light output level for tungsten light sources that are low in blue wavelengths. In fact, that curve is quite close to 80A color temperature conversion filter! No, it's probably more close to 80B or even 80C. There's so much red passed.
There are also real blue filters available, and when I speak about blue filter, I really mean blue filter.
i realized early on into this thread that i was saying "ortho" when i meant something different ..
i meant blue sensitive ( only!) orthochromatic ( not sensitized with dye ) film, like pre-1870s plates ... the baseline .
at present i am shooting paper negatives, a lot of them, and i was wondering if there was a
film equivalent to my paper negatives ... some of the papers i shoot are vc, and some are graded..
i also do some UV exposures, ... so in the end maybe just a bluish ( i will have to experiment, dark , light, greenish/cyanish )
and filter might works best.
as chemical photography marches forward, it seems that we are going backwards at the same time ..
i kind of hope that down the road there is a manufacturer of just plain old blue sensitive ortho film / plates
instead of pan film. i know it is inferior, and difficult to harness the contrast, and "deal with" because
of its slowness ( dyes increase the speed ) but it would be kind of nice to see a drastic change.
instead of chemical photography trying to keep up all the BS that the digi folks want us to worry about,
( we've already lost color image making to the computer ) i'd like to hunker down
and get back to the roots of photography. i know i am probably a minority,
but images from that early time period seem to be much more interesting than
things made in the last 100 years ...
thanks again for all your help, suggestions and information / education ..
john
No, this filter is advertized as blue filter for b&w and not as correction filter. This is from Heliopan using Schott glass. Older B&W filter catalogs show similar curves for the blue filter.
I found much narrower response for wratten gel filters but even these went up to 500nm. IDK if these are available as glass filters.
"Ortho" film usually means it IS spectrally sensitized (with sensitizing dye) for green wavelengths, in addition to blue. Non-sensitized emulsion is blue-sensitive only. Those are also available for some special purposes such as copy films as mentioned before in this thread.
Among other consequences, all that means that to mimic a plain emulsion with a pan film and filters, use a blue filter. To mimic an ortho emulsion, use a cyan filter which passes blue and green.
Sorry to mix things up, but I'm rather confused.
I'd like to simulate non-sensitized emulsion (like wet plate collodion) with an ortho emulsion, which filter should I use? From what has been said, I understand that I could achieve the same effect with a panchromatic film and a deep blue filter like a 47b, but I haven't quite understood what filter is best with orthochromatic emulsion...if anyone could shed some light on the matter, I'd be extremely grateful
I was also wondering if anyone had any experience developing Ilford Ortho Plus with Rollei Low Contrast developer for pictorial use. I took a couple of portraits in the studio, exposing the film at 50 iso and I can't find info on this combination anywhere
Thanks
Thanks for your advice, but I may have to just guess the time as I don't have the facilities to develop by inspection at home.
I just got a bargain minus red filter on ebay and I'll try it as soon as it arrives to see how it works with ortho film, but, from what I've been told, I may as well have bought normal panchromatic film to test with that filter as the effect would be the same.
Do not use a red filter with orthochromatic film unless you want unexposed negatives.
<snip>
Anyone else miss Panalure? Any chance of pursuading one of the European paper makers to make something like it again?
/digression.
(Ilford Ortho Plus in Rollei RLC)
[...]
It would follow that it might need around 10 1/2 minutes (8 minutes times ~1.33) in RLC 1+4. That's at box speed, which is supposed to be 80 in daylight, 40 in tungsten---I don't know what your lighting was, but you might fiddle that time to compensate one way or the other since you exposed at a speed somewhere between the two.
[...]
Yeah, don't waste your ortho film on testing it---it blocks wavelengths that the ortho film can't see, so it should have no effect to speak of. But it should give you an orthochromatic-looking image on pan film.
-NT
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