B&W Filters w/ Color Film

[Mike1234]

Greetings All!!

GIVEN: Shooting color neg film, scanning, printing B&W.

I'm well aware of the effect of deep color filters on B&W film. I'm also aware that color ranges can be lightened or darkened in PS and that color channels can be deleted or individually manipulated, etc. However, overdone, this creates noise and other unwanted problems.

What I DON'T know is how deeply colored filters used with color negative film affects color brightness when the scanned image is converted to grayscale. For example, would using a #25 or 29 red filter darken blue sky and green foliage in the scan. If so, by how much? Same question for deep green, blue, etc. Has anyone tried this? If the filters have a significant effect it seems appropriate to use them in lieu of excessive post processing.

[bob carnie]

If your end result is a black and white print and you use colour film I see absolutley no reason not to use filters to adjust tonal values.
I have not heard of anyone doing this , but worth investigating

FWIW I have converted crossed process film to black and white with great results, opinions may vary but I believe heavily filtered colour film will create some great effects.

[Mike1234]

Thanks, Bob. It seems I'll be doing some testing very soon. I'll post my findings.

[David A. Goldfarb]

I think it would work, but it seems to me that it would make more sense to do it in software with channel mixer, if you plan to shoot color to print B&W, so you can shoot the film at the full speed without having to compensate for a filter on the lens, and because the filter is a source of flare.

[Mike1234]

Hi David!!

I understand your reasoning but my goal is ultimate final print quality. If I make BIG changes to the brightness of a given color or colors I always end up adding noise.

BTW, I would shoot one image with and another without filtration so I always have the option of printing color. I'm going to try some tests to determine if there's any merit to my hypothesis.

[bob carnie]

Give it a go,
I have a lot of film that I crossed processed for John Callow here, and for fun converted to black and white .
John not only shoots cross processed but also night scenes with extremely long exposures.
When converted to black and white we got some very good conversions.

Just remember that you are in territory that may take a lot of testing and lots of unpredictability.
I do a lot of channel blending of colour images to build up the **weight ** of an image then use luminosity to hide the wonky colours , what you are doing is making the moves at time of original capture which should give you some very good results.

Thanks, Bob. It seems I'll be doing some testing very soon. I'll post my findings.

[Mike1234]

Do you guys think a color chart is the best test subject? The even/smooth toned patches should reveal noise levels quite easily. Or is there a color chart with graduated tones, i.e. red-to-blue, blue-to-yellow, yellow-to-red, cyan-to-magenta, etc.? I suppose I could just make the latter. A home-made garduated color chart would serve this purpose nicely, I think, because it's not "color accuracy" I'm concerned about. It should still serve the purpose of showing noise, banding, and other bad stuff.

[bob carnie]

Mike
A colour chart may not be required , you will know immediately by scanning and looking at the channels if you are inducing unwanted noise.
Rather I would experiment more with subject matter you enjoy first, make some prints and see if it is any better than regular colour exposure , scan and print.
It should be pretty obvious you are on the right track after a couple of side by side roll tests..

Do you guys think a color chart is the best test subject? The even/smooth toned patches should reveal noise levels quite easily. Or is there a color chart with graduated tones, i.e. red-to-blue, blue-to-yellow, yellow-to-red, cyan-to-magenta, etc.? I suppose I could just make the latter. A home-made garduated color chart would serve this purpose nicely, I think, because it's not "color accuracy" I'm concerned about. It should still serve the purpose of showing noise, banding, and other bad stuff.

[Mike1234]

That's true, Bob. I'll probably test both ways just for the fun of learning something new.

Years ago I tested the long-believed theory that opening and re-saving a JPEG many times caused increasingly obvious artifacts. What I found is, unless fairly obvious changes were made between saves, it made no perceivable difference. I used, real images, graduated color patches and solid color patches.

I just need to see for myself because I'm overly pragmatic... I have to see/learn for myself.

[Bruce Watson]

...my goal is ultimate final print quality.

Then I don't understand what you're trying to accomplish. If you want ultimate B&W print quality, use a B&W film for capture. For the same ISO rating, B&W negative film is both sharper and less grainy than color negative film. If you want the linearity of color negative film spectral response, use one of the Tmax films.

It looks to me as if you are trying to make this harder than it actually is. Like you are chasing a magic bullet. To find out, make sure you can define the problem. You can't solve a problem you can't define. So... what are you trying to do with color film that you can't do with B&W?

But to answer your original question about filters, the laws of physics won't change depending on what film you use to make the capture. A red filter will still pass the longer wave lengths and block the shorter ones. And the film will still record what it sees, regardless of B&W or color. Depending on how you scan the film and convert to grayscale, capture to B&W or color negative film should give you similar results.