Color photography with black and white film

[dh003i]

Swilf,

This is a beautiful result, thank you for posting it. You say that you use a Hitech #47 with the Cokin X-PRO system. However, the X-PRO system takes filters 130mm wide. I only see a 4 x 4in (100 x 100 mm) filter on BH Photo.

I've got some pleasing result with Cokin 003 (red) and Cokin 004 (green). Had no chance to compare them to the recommended #25 and #58, but the picture looks good:



(sorry, it's MF)

As you already mentioned, there's no blue filter in the system, so I had to buy Hitech #47, but at least 2 of 3 filters are cheap. Anyway, spectral sensitivity of the film in use should be much more of a concern.

[D. Bryant]

I've got some pleasing result with Cokin 003 (red) and Cokin 004 (green). Had no chance to compare them to the recommended #25 and #58, but the picture looks good:



(sorry, it's MF)

As you already mentioned, there's no blue filter in the system, so I had to buy Hitech #47, but at least 2 of 3 filters are cheap. Anyway, spectral sensitivity of the film in use should be much more of a concern.

So what kind of film did you use?

[swilf]

You say that you use a Hitech #47 with the Cokin X-PRO system. However, the X-PRO system takes filters 130mm wide.

Glad you like it. No, I didn't use Cokin X-Pro, I used Cokin P, but there should be no difference. After all, they are just sheets of plastic cut to size. And we are too far anyway from meeting Luther-Ives condition to care about filters' spectral densities, exact brands or Wratten numbers. Almost any deep red, blue and green should be OK. The deeper the better: dense filters produce saturated colors.

As for film, I used TMX. I suggest generous bracketing for red and for blue.

[Corran]

So this is really intriguing me and I have some ideas that I would love to do this with.

There is 19 pages of this thread though, so can someone sum up the pertinent info? Like, what the specific 3 filters you would need for this are and what filter factor to use for the film when using them? There was lots of discussion and it was a bit confusing as to what was right.

[Ben Syverson]

You really only need two filters. For example, you might have one Red image, one Green, and one RGB (panchromatic). You can derive the blue record with:
B = RGB - (R+G);

The blue filter is quite dark, which means you're either exposing for longer or living with a thin negative. This gets around that limitation.

Another thing to try would be orthochromatic (blue-sensitive) film for the B record.

[Drew Wiley]

A simple trick is to use TMX100 for R & G, but TMY400 for B. You will need to dev B
neg longer, but it's not too diffcult to match the curves. Also, a 47 filter is not too
bad and about a stop faster than the ideal 47B.

[Corran]

I will try just taking an R and G and subtracting it from an RGB exposure (which is convenient to have a "straight" b&w). Kind of reminds me of some of the audio tricks we use for stereo images in recording.

Do you think an X1 green filter will work instead of a stronger green filter? I don't have a #58 and don't feel like buying a $50 filter for simply testing this idea.

Thanks!

[Tocal]

Hi everybody.

I finally managed to read the whole thread. Separation is indeed a very interesting technique.

Now, a Sinar 4-lens board with lenses crossed my way accidentially and I wasn´t able to resist. I´ll try to start one-shot seperation with it on 4x5. I don´t expect the Schneider 125/8 Radionars to be astounding, but it is a start. Hopefully I can manage to get rid of the parrallax-error using photoshop.

I will report here once my project is going to start.

Best regards,

Tobias

[D. Bryant]

I've got some pleasing result with Cokin 003 (red) and Cokin 004 (green). Had no chance to compare them to the recommended #25 and #58, but the picture looks good:

(sorry, it's MF)

As you already mentioned, there's no blue filter in the system, so I had to buy Hitech #47, but at least 2 of 3 filters are cheap. Anyway, spectral sensitivity of the film in use should be much more of a concern.

Just noticed that your background isn't a uniform color. Interesting.

[swilf]

Just noticed that your background isn't a uniform color. Interesting.

Yes, this is a mistake in matching all three curves at highlights. Shadows are slightly greenish too, I should have been more accurate. Hint: include Q-13 when possible.