Red Filter?

Aaron Bernard · July 19, 2005

Ive been doing a lot of black and white conversions lately and was doing some reading in general about B&W. During my reading I came across the idea that people use a red filter (#25 or so) to darken up the sky and bring more contrast into the image. Now Im assuming this would only work on a film camera with B&W film loaded??

Is this correct or is there any use at all on a color digital camera (D70) for a red filter? :dunno

wxwax · July 19, 2005

A polarizing filter achieves some of the same effects in color. The polarizer saturates colors. It has the effect of making the sky a deeper blue, and greens really pop a well. It's well suited to landscapes.

If you have a digital camera, make sure you get a circular polarizer. A linear polarizer will not work.

4labs · July 19, 2005

FastScan wrote:

Ive been doing a lot of black and white conversions lately and was doing some reading in general about B&W. During my reading I came across the idea that people use a red filter (#25 or so) to darken up the sky and bring more contrast into the image. Now Im assuming this would only work on a film camera with B&W film loaded??

Is this correct or is there any use at all on a color digital camera (D70) for a red filter?

IMHO I would forget the filter and get the image factory software. It lets you simulate any color filter and I have gotten great results with it...

wxwax · July 19, 2005

4labs wrote:

IMHO I would forget the filter and get the image factory software. It lets you simulate any color filter and I have gotten great results with it...

I see what you're saying, but I'm not sure you can duplicate a polarizing filter in Photoshop, can you? Color filters, yes, but I'm not aware of a way to mimic a polarizer.

4labs · July 19, 2005

wxwax wrote:

I see what you're saying, but I'm not sure you can duplicate a polarizing filter in Photoshop, can you? Color filters, yes, but I'm not aware of a way to mimic a polarizer.

I wouldn't think there would be a need for a polarizer if you are shooting BW film?If you just want to darken the sky , just use a red filter in Photoshop.

Aaron Bernard · July 19, 2005

4labs wrote:

I wouldn't think there would be a need for a polarizer if you are shooting BW film?If you just want to darken the sky , just use a red filter in Photoshop.

OK this is getting funny. Its like that game where you tell someone one thing and then it comes back to you totally differant.

Ive got a polarizer and I enjoy the results from that when I shoot and convert to B&W. Ive also got access to a red filter and actually just tried it.
I get a nice red image... everything is red!

not the effect I was looking for. So I guess you have to be using B&W film for the red filter to do its job properly.

wxwax · July 19, 2005

FastScan wrote:

OK this is getting funny. Its like that game where you tell someone one thing and then it comes back to you totally differant.

Ive got a polarizer and I enjoy the results from that when I shoot and convert to B&W. Ive also got access to a red filter and actually just tried it.
I get a nice red image... everything is red! not the effect I was looking for. So I guess you have to be using B&W film for the red filter to do its job properly.

Yes, that's right. Otherwise, it's just a red filter.

wxwax · July 19, 2005

4labs wrote:

I wouldn't think there would be a need for a polarizer if you are shooting BW film?If you just want to darken the sky , just use a red filter in Photoshop.

I was just answering the bit where he asked if there was a use for a red filter in color.

Phil U. · July 20, 2005

FastScan wrote:

OK this is getting funny. Its like that game where you tell someone one thing and then it comes back to you totally differant.

Ive got a polarizer and I enjoy the results from that when I shoot and convert to B&W. Ive also got access to a red filter and actually just tried it.
I get a nice red image... everything is red! not the effect I was looking for. So I guess you have to be using B&W film for the red filter to do its job properly.

You can take that red image and do a B&W conversion from it. You will notice a different look (different tonality) in it as compared to a shot without the filter converted to B&W with the same parameters.

However, you can achieve the same results without having to use the filter during the shoot. There are different B&W conversion techniques out there. During this process you can adjust what colors from the color image you want to use to obtain the B&W tonality you want in the final image. Do a search for B&W conversion techniques and play around with the "Channel Mixer" method - this is an easy way to see what the effects are of using different mixtures of color for the resulting B&W image.

B&W Film photographers use(d) different color filters (I believe Red is probably the most used) to achieve this effect to get the tonality they want(ed).

Aaron Bernard · July 20, 2005

OK. Im going to try a B&W conversion on the Red image just for kicks. I'll post the results here...

thanks!

Aaron Bernard · July 20, 2005

I did some shots with the red filter. Check it out here:

http://www.5road.com/redfilter/index.html

See the results for yourself. In the end the images almost look the same. I did an auto levels on both the color version and the red filter version just to see how it would come out. At 100% the red filter version is much less noisy than the color version. Could be the quick conversion method I used though. At any rate this test shows you can use a Red filter on a DSLR to do B&W. Dunno if there is a reason to yet but it will work. Im going to play around with it some more now that I have the filter.

One side effect is that the red filter cuts down your stops almost like an ND filter.

blackwaterstudio · July 21, 2005

IF you have a Canon 20D you can set the red filter in the camera to whatever you like while turning off the blue and green channels.

Red Filter?

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