Black and white filters and purple flowers

I hope I am posting this to the right part of the forum.

This spring I plan to make a trip to The White Mountains of NH and photograph the blooming lupines (tall, purple flowers). My focus lately is black and white. While I will likely bring my digital camera to capture these scenes in colour, I want to attempt to photograph them with black and white film. Both for the challenge and so I can print them in my darkroom. The problem is I want to create some contrast between the flowers and rest of the plants. An unfiltered exposure may produce and image where the flowers are the same shades of grey as their stalks.

Using filters for black and white photography is something I am still getting the hang of and I currently only own orange and red filters. I am familiar with the relationship between a filter lightening like colors and darkening its complimentary color. A red rose with a red filter will make the flower appear a rather light tone compared to its stalk for example. However, there are no violet/purple filters that I am aware of. Blue is a neighboring color to purple, but I do not know if that would be enough to lighten the flowers. The additional properties of using blue filters for landscape may also be undesirable (increased haze and lightened sky).

A green filter may be another potential approach. Perhaps it would lighten the green stalk to create some contrast against the purple flowers? Though given I have not yet used a green filter or photographed these flowers before, I am uncertain if the effect will be enough.

Looking for any thoughts, ideas, or insights into how I might tackle this!

That purple is pretty close to photographic blue, so a yellow filter should darken the lupines nicely.
For the ones tat are more purple, yellow-green would darken them more.

Testing will reveal. For flowers versus leaves contrast I carry three filters; dark blue, red, and green.
By putting the filters quickly to the eye it is easy to see which makes the subject "pop". For example the deep blue filter might render the lupines as pale flowers against black leaves while the green filter could deliver dark flowers against light leaves. Either possibility may be a good or bad tonal distortion; judgement call required.

Purple color in plants is usually a result of anthocyanins. These don't have a fixed color as they can change color with pH and metal complexing.

If the lupins are blue then a green filter (peak absorbance around 510nM) should result in dark lupines against light foliage. If you want light flowers against dark foliage then a magenta filter would be the better choice, especially for purple lupins.

Magenta filters are hard to come by. I use 3x3" squares cut from a Rosco filter booklet: https://www.bhphotovideo.com/c/product/45190-REG/Rosco_8815_Roscolux_Designer_Color_Selector.html

The Blue 80-A which was used for color balance of tungsten lights in the past should do a good job on the lupins and you can pick up a used one for not much money since almost no one used them any longer.

You'll want to test things to see what works for you. I always have a K2 filter attached to my camera lens and I always shoot B&W films, so I know pretty much what to expect. A green filter can be handy, no help w/ the skies and clouds though. An orange never did much except for maybe portraits. A yellow filter and B&W film is a very old, classic look.

If you're after flower pics, a roll of orthochromatic film would be fun.

If you're shooting 35mm then you have the luxury of shooting with a K, G, and 80-a to see what works out the best.

I second the suggestion to view the flowers through your filters to see the effect. With colored flowers, especially purple, which contains blue and red and who knows what other colors, that is one of the best ways to get an idea of what color contrast is going to do.

I also like the idea of blue and/or magenta filters. An 80B or 80A shouldn't be too hard to come by used; they were rather plentiful once. For magenta, Nicholas' suggestion is likely best.

Doremus

Here is an example of purple flowers (nettles), yellow flowers (mustard) and sky. Med Y on Ilford FP4+ (DDX- The Darkroom)

trail by Mark Wyatt, on Flickr

Doremus Scudder said:

I second the suggestion to view the flowers through your filters to see the effect. With colored flowers, especially purple, which contains blue and red and who knows what other colors, that is one of the best ways to get an idea of what color contrast is going to do.

I also like the idea of blue and/or magenta filters. An 80B or 80A shouldn't be too hard to come by used; they were rather plentiful once. For magenta, Nicholas' suggestion is likely best.

Doremus

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The dreaded two lettered troll said that Magenta is not a color. He argued with PE and me about that.

A flourescent correction filter for color film is a light magenta color. I couldnt say if it would give you the required contrast though.

glbeas said:

A fluorescent correction filter for color film is a light magenta color. I couldn't say if it would give you the required contrast though.

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I imagine one of the easiest sources for an optical-quality magenta filter would be to simply use the #5 filter from an Ilford under-the-lens Multigrade filter kit. They're plentiful and should do the trick nicely. If one needed less contrast, one could use a weaker filter, say #3 or #4.

Doremus

Thanks for the replies and suggestions everyone. I've been really thinking about this trying to figure out the best approach to this since I may be using my 4x5 so total exposures will be limited. Given more thought, I worry that attempting to lighten the flowers using orthochromatic film or a blue/violet filter may lighten my sky too much. I tend to shoot and dawn and dusk so I as of yet unsure how strong that effect will be.

The opposite approach of attempting to the darken the flowers (while not what I had envisioned) could be the better option. The suggestion of using a yellow or yellow-green filter may be the way to go.

I agree Nicholas is on the right track. But how about a post-Valentine's-Day trip to the florist or local supermarket to pick up flowers similar in color to those lupines or anything else you hope to photograph? Use a roll or two of 35mm or 120 (assuming you have a 35mm or MF camera available) of the same emulsion type you plan to use in 4x5, in the same general lighting conditions you expect, to evaluate the effects of various filters and figure out how to get what you want .