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Author Topic: "Red"scaled B&W?  (Read 2631 times)

Indofunk

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"Red"scaled B&W?
« on: August 19, 2015, 03:58:38 PM »
I'm about to do a filmswap with LA where he shoots a roll of CN film straight at box speed, gives it to me, I redscale it, and shoot it at maybe +4EV. Anyways, that got me thinking, and go with me here because didn't someone famous say there's no such thing as a stupid question? Well, I'm about to prove that wrong. Are all B&W films just a single layer of silver? How about chromogenic B&W films? If there's any layering at all, then there might be some sort of effect on the neg if you flip it, even if it's very subtle. Maybe like using a red filter? Anyways, there's your stupid question for the day, no more dumb questions until tomorrow :)
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jharr

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Re: "Red"scaled B&W?
« Reply #1 on: August 19, 2015, 04:11:33 PM »
The first question that leaps to my mind is whether the antihalation layer is different (more opaque?) on b/w film than on CN film. Just about all of the b/w film bases I know of are clear (not orange). This diagram makes me think it is just a single emulsion layer with the requisite adhesives and protective coating.

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Indofunk

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Re: "Red"scaled B&W?
« Reply #2 on: August 19, 2015, 04:16:17 PM »
XP2 comes out purple-toned when developed in C41. I don't think that's an anti-halation layer or anything, I think it's just the way the silver looks when developed.

Anyways, I'm out of dumb questions for the day so I won't ask anymore :)
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Pete_R

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Re: "Red"scaled B&W?
« Reply #3 on: August 19, 2015, 05:40:09 PM »
All the silver gets removed in C41 and you're left with dyes only. According to Ilford, the pink/purple colour "is caused by the bleaching of the small amount of sensitising dye that remains in the emulsion after processing". But I get the same thing when processing XP2 in black and white chemicals with no bleach so I'm not sure. But I don't think the colour is inherent in the film, it only appears after processing, so wouldn't have any effect during exposure.
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Indofunk

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Re: "Red"scaled B&W?
« Reply #4 on: August 19, 2015, 06:06:38 PM »
Ah, makes sense. Oh well, just a silly thought for the day. You may now go back to your regularly scheduled, NON-stupid questions :D
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Francois

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Re: "Red"scaled B&W?
« Reply #5 on: August 19, 2015, 08:42:56 PM »
I don't get it... what's the point in redscaling B&W film since what most people are after with redscaled film is in color?

You won't get an orange golden tone, just B&W a mirror image with long exposure.
Might as well just use a tripod and a deep ND filter.
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Francois

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