# Converting C41 as B+W

**URL:** <https://forums.negativelabpro.com/t/converting-c41-as-b-w/7034>\
**Category:** General Film Photography\
**Created:** [November 10, 2023, 3:29am UTC](https://forums.negativelabpro.com/t/converting-c41-as-b-w/7034 "2023-11-10T03:29:46Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![wbhub](https://avatars.discourse-cdn.com/v4/letter/w/8491ac/32.png) [@wbhub](https://forums.negativelabpro.com/u/wbhub)\
**Post date:** [November 10, 2023, 3:29am UTC](https://forums.negativelabpro.com/t/converting-c41-as-b-w/7034/1 "2023-11-10T03:29:46Z")

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Hey everyone! I’m wondering what differences there are, if any, between shooting on a tabular grain C41 film (like Portra 400) and converting as B+W vs. shooting on a tabular grain B+W film (like T-MAX 400).

Will the final image characteristics be meaningfully different for two films with the same ISO (Portra 400 vs T-MAX 400)? If so, how?

Does anyone know of a side-by-side test comparing this?

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**Author:** ![Harry](https://avatars.discourse-cdn.com/v4/letter/h/f6c823/32.png) [@Harry](https://forums.negativelabpro.com/u/Harry)\
**Post date:** [November 10, 2023, 7:25am UTC](https://forums.negativelabpro.com/t/converting-c41-as-b-w/7034/2 "2023-11-10T07:25:27Z")

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Well there is a fundamental difference in that there is no orange mask on chromagenic B&W films so the dynamic range of the scene is spread across that of your sensor, that’s got to be better I would have thought. I don’t think I’ve ever tested it though.

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**Author:** ![cvandebroek](https://avatars.discourse-cdn.com/v4/letter/c/50afbb/32.png) [@cvandebroek](https://forums.negativelabpro.com/u/cvandebroek)\
**Post date:** [November 10, 2023, 3:45pm UTC](https://forums.negativelabpro.com/t/converting-c41-as-b-w/7034/3 "2023-11-10T15:45:33Z")

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Exchanging out of theory, as I’ve never done a side-by-side comparison, not to mention considered shooting C41 film to have b&w images.

The spectral sensitivities are different, so the results will differ, too. Tmax is known to have less sensitivity for blues resulting in darker tones (for blues) vs. other Kodak b&w films. Portra 400 on the other hand has a quite high sensitivity for blues, so a conversion to b&w will look different initially. You could tweak the colour interpretation to your liking in post though.