Henry
Well-known
Does black and white film have well understood white balance levels? For color film I have no trouble funding their stated color balance, but for black and white I have been less successful, but it’s possible that I just don’t know how to read the information slips.
Obviously different films would likely be different, but how would something like Hp5 compare to TMax in terms of white balance?
If I am asking the question in the wrong way, feel free to set me right.
Obviously different films would likely be different, but how would something like Hp5 compare to TMax in terms of white balance?
If I am asking the question in the wrong way, feel free to set me right.
retinax
Well-known
Assuming that you're not pulling our legs, take a minute to think about what white balance does. It's about colours, right? And you're asking about black and white film...
Or are you thinking about spectral response?
Or are you thinking about spectral response?
Henry
Well-known
This is a related to how I asked the question maybe?
For sure black and white film responds to different wavelengths differently, I perhaps only know how to refer to this as color balance. In color film it translates to a WB value. Is black and white simply expressed differently?
For sure black and white film responds to different wavelengths differently, I perhaps only know how to refer to this as color balance. In color film it translates to a WB value. Is black and white simply expressed differently?
benlees
Well-known
Obviously, panchromatic b&w film (most modern ones like HP5+) will show shades of grey instead of the influence of different hues of colour that may make a colour photo look off to our eyes, or an ortho b&w image. Whether you can actually notice the hue in the grey is another matter. You can always use filters if your b&w images don't match what you see...
retinax
Well-known
Aha, yes what you mean is called spectral response. Manufacturers publish spectral response curves. White balance is a concept from digital photography afaic, and there's daylight/tungsten balance in colour film, and, only somewhat related, colour balancing. These aren't closely related to spectral response.
Henry
Well-known
Thank you! This makes some of these inserts make a lot more sense to me.
Henry
Well-known
So, if I look at spectral sensitivity graphs form Velvia vs HP5
https://www.fujifilm.com/products/professional_films/pdf/velvia_50_datasheet.pdf
https://www.ilfordphoto.com/amfile/file/download/file/1903/product/691/
Ignoring that one has different dye sensitivity levels specified, I can figure out how they compare. This makes a lot more sense to me than whatever I was imagining.
https://www.fujifilm.com/products/professional_films/pdf/velvia_50_datasheet.pdf
https://www.ilfordphoto.com/amfile/file/download/file/1903/product/691/
Ignoring that one has different dye sensitivity levels specified, I can figure out how they compare. This makes a lot more sense to me than whatever I was imagining.
ranger9
Well-known
Freakscene
Obscure member
It is hard to compare when B&W film renders a spectrum as a density curve in monochrome and colour film renders it as, well, colours. Also bear in mind that the density curves for both films will be calculated with a specified, usually fairly narrow wavelength.
Marty
Henry
Well-known
I see, interesting.
My motivation for this question is related to converting color raw images into black and white images. I am wondering if understanding how a film responds to color to create density could help me think through some conversions.
narsuitus
Well-known
Some black & white films respond differently to infrared light, ultra violet light, and visible light. Are those the type of films you are questioning?
Henry
Well-known
I was more referring to how different types of visible light might change the resulting response on the film, coupled with my background in digital where white balance directly impacts how an image is rendered in black and white.
Freakscene
Obscure member
The primary consideration is spectral sensitivity, because in B&W films the density curve is influenced heavily by development. If you look at the B&W film presets in any monochrome image manipulation software, these are usually based on spectral sensitivity. Given how these mostly produce images that look very little like the films, spectral sensitivity alone won't get you there. You can superimpose the spectral sensitivity and the density curve to get somewhere closer to the look of your chosen B&W film. Good luck, it's not easy.
Marty
Henry
Well-known
This sounds like a reason to learn some image processing libraries, or how to use photoshop better to apply something like that. At this point in my life I think learning new image processing methods sounds more interesting.
Side thought, I wonder if there are good processing libraries for node.js
And now I have to things to look up! Thanks!
Beemermark
Veteran
Shooting B&W film (maybe not applicable to the question) but the "color" of daylight has an effect on the B&W response. With color film you use color filters to correct the effect of daylight usually in terms of temperature. With B&W film you use contrast filters.