Newbie Pinhole B&W Filter Question

BobClack · Jan 22, 2017

Cannot find an answer to this on the internet and can only find answer to this on APUG in terms of shooting paper negatives.

Camera: Pinhole Blender 35mm.
Film: Kodak Tri-X 400, Polypan F (ASA50).

I'd like to use either a yellow, orange or red gel filter on the camera for shooting b&w film. However, nowhere can I find a chart listing what the increase in exposure time would be using a filter once reciprocity failure is determined for the film.

And since no one seems to be even asking the question, am I missing something here?

Is it all just "experiment and find out"?

Thanks in advance.

jbrubaker · Jan 22, 2017

I don't think filters are often used for pinhole exposures. Even a 1 stop exposure increase will double your exposure time, which is already quite long. ---john.

AgX · Jan 22, 2017

There is not something as a common filter factor for a filter.

In first instance such factor depends on what effect you want to achieve. You may even expose without any correction.
In second instance, but of lesser effect is the spectral sensitivity of a film

Sirius Glass · Jan 22, 2017

Generally each filter has its own filter factor, the following is typical ranges:

Yellow 1 to 2 times longer - filter factor ~= 1 to 1.5
Orange 2 to 3 times longer - filter factor ~= 2 to 2.5
Red 6 to 8 times longer - filter factor ~= 3

Mathematically think 2filter factor = times longer

tezzasmall · Jan 22, 2017

I've done a bit of pinhole over the years, both with paper and film for negatives and I've never thought of putting a filter on for film for some reason (although more recently I have been putting a yellow one on for paper negs). So like the original poster I'd too be curious to the answer.

EDIT: Just googled twice = 'film reciprocity failure table' and 'tri x film reciprocity failure table' and both list various times with the top result being helpful (although others may also be be further down the list): https://mkaz.com/film-reciprocity-tables/ .

Once you've got your basic exposure sorted out from the table, adjust it for the various filters:
yellow filter = + 1 extra stop; orange = + 2 stops; and red filter = + 3 stops.

Hope this is of some help.

Terry S

NedL · Jan 22, 2017

Since you are using pan films, I think the correction factors listed by Sirius and Tezza are probably about right, and then look up reciprocity correction for your film. I have only used filters with pinhole photography a few times... any dust or water marks on the filter will be exaggerated. If possible, I would hold the filter in front of the pinhole and move it around during the exposure. Have fun!

Bill Burk · Jan 22, 2017

NedL said:
Since you are using pan films, I think the correction factors listed by Sirius and Tezza are probably about right, and then look up reciprocity correction for your film. I have only used filters with pinhole photography a few times... any dust or water marks on the filter will be exaggerated. If possible, I would hold the filter in front of the pinhole and move it around during the exposure. Have fun!

Smart advice!

RalphLambrecht · Jan 23, 2017

BobClack said:
Cannot find an answer to this on the internet and can only find answer to this on APUG in terms of shooting paper negatives.

Camera: Pinhole Blender 35mm.
Film: Kodak Tri-X 400, Polypan F (ASA50).

I'd like to use either a yellow, orange or red gel filter on the camera for shooting b&w film. However, nowhere can I find a chart listing what the increase in exposure time would be using a filter once reciprocity failure is determined for the film.

And since no one seems to be even asking the question, am I missing something here?

Is it all just "experiment and find out"?

Thanks in advance.

a yellow filter will need to add one stop to the exposure but give you much better contrast.

BobClack · Jan 26, 2017

Thank you to all responders. The answers here have helped 100%.

Being new to pinhole photography, I thought that the filter factors used in standard lens photography might not apply in pinhole work. A case of overthinking!

I regularly use the filter factors as shown above (thanks Sirius Glass!) when shooting Tri-X 400 on my Nikon FE or Minolta SRT-201 and now see that the same filter factors do apply in pinhole shooting.

Thanks once again to all!

kier · Feb 6, 2017

Yeah exposure is exposure is exposure, so your filter factors will be the same. BUT, I think you might be headed towards one mistake. You should apply the filter factor to your metered exposure FIRST. THEN apply your reciprocity correction to the factored exposure time. If you apply reciprocity first, then filter factor, you run the risk of running afoul of your new reciprocity needs.

For example, ACROS needs no correction <2 mins. Say your exposure meters at 30 seconds - no reciprocity there. Say you want to use a red filter (3 stops), for a factored exposure of 4 minutes. Now you do need reciprocity correction. So, first do your filter factor (4 mins), then apply reciprocity on that 4 minute exposure for your final, corrected, exposure.

Make sense?

dasBlute · Feb 6, 2017

I have a yellow filter permanently *taped* to the front of my pinhole,
it keeps out dust and indeed, adds contrast.

I add a stop of exposure, then calc the reciprocity... just as mentioned above

RalphLambrecht · Feb 7, 2017

BobClack said:
Cannot find an answer to this on the internet and can only find answer to this on APUG in terms of shooting paper negatives.

Camera: Pinhole Blender 35mm.
Film: Kodak Tri-X 400, Polypan F (ASA50).

I'd like to use either a yellow, orange or red gel filter on the camera for shooting b&w film. However, nowhere can I find a chart listing what the increase in exposure time would be using a filter once reciprocity failure is determined for the film.

And since no one seems to be even asking the question, am I missing something here?

Is it all just "experiment and find out"?

Thanks in advance.

yellow filter needs about one extra stop of exposure(+1)this is independent of reciprocity failure or bellows extension and will always be one extra stop.I would determine the basic exposure, add the stop and then consider reciprocity to get to the final exposure time.so, in fact, the filter will make the reciprocity failure worse,unfortunately.

bkarasek · Feb 7, 2017

RalphLambrecht said:
yellow filter needs about one extra stop of exposure(+1)this is independent of reciprocity failure or bellows extension and will always be one extra stop.I would determine the basic exposure, add the stop and then consider reciprocity to get to the final exposure time.so, in fact, the filter will make the reciprocity failure worse,unfortunately.

I don't know if I would call extended reciprocity "worse". It depends on what you want..... I like the increase in contrast that a yellow or Orange filter gives and 2x or 4x increase in exposure is not an issue..... 30 minutes becomes 60 min... I use the time to set up other pinhole cameras.

NedL · Feb 7, 2017

bkarasek said:
..... 30 minutes becomes 60 min... I use the time to set up other pinhole cameras.

Spoken like a true pinholer, couldn't agree more! I usually set mine up, keep walking the dog, and loop back around to pick them up.

BobClack · Feb 18, 2017

kier said:
Yeah exposure is exposure is exposure, so your filter factors will be the same. BUT, I think you might be headed towards one mistake. You should apply the filter factor to your metered exposure FIRST. THEN apply your reciprocity correction to the factored exposure time. If you apply reciprocity first, then filter factor, you run the risk of running afoul of your new reciprocity needs.

For example, ACROS needs no correction <2 mins. Say your exposure meters at 30 seconds - no reciprocity there. Say you want to use a red filter (3 stops), for a factored exposure of 4 minutes. Now you do need reciprocity correction. So, first do your filter factor (4 mins), then apply reciprocity on that 4 minute exposure for your final, corrected, exposure.

Make sense?

Yes and thanks kier. Totally makes sense! Bob

RalphLambrecht · Feb 18, 2017

BobClack said:
Cannot find an answer to this on the internet and can only find answer to this on APUG in terms of shooting paper negatives.

Camera: Pinhole Blender 35mm.
Film: Kodak Tri-X 400, Polypan F (ASA50).

I'd like to use either a yellow, orange or red gel filter on the camera for shooting b&w film. However, nowhere can I find a chart listing what the increase in exposure time would be using a filter once reciprocity failure is determined for the film.

And since no one seems to be even asking the question, am I missing something here?

Is it all just "experiment and find out"?

Thanks in advance.

for a yellow filter add a stop of exposure;for orange add a stop and a half.

Rich Ullsmith · Feb 18, 2017

Figure this. I shoot 100asa film with red25filters, f250 (equivalent) pinhole.

I meter at f64, then add four more stops to get to f250. Add another 2.5 stops for the filter. Then add reciprocity, which by now is way up on the steep end of the curve.

What I am getting at is: any error in metering (and there will be error!) is amplified by doubling 6.5 times, then that error is applied to a reciprocity graph.

So, while it might be instructive to initially do all this math including filter factors, it is going to involve (sigh) experimentation.

TheToadMen · Feb 18, 2017

Rich Ullsmith said:
So, while it might be instructive to initially do all this math including filter factors, it is going to involve (sigh) experimentation.

Metering by guestimation ... works for me !

(I just count to 40-ish all the time)

Rich Ullsmith · Feb 18, 2017

Nice, it appears that 40-ish works.

BobClack · Feb 18, 2017

Rich Ullsmith said:
Figure this. I shoot 100asa film with red25filters, f250 (equivalent) pinhole.

I meter at f64, then add four more stops to get to f250. Add another 2.5 stops for the filter. Then add reciprocity, which by now is way up on the steep end of the curve.

What I am getting at is: any error in metering (and there will be error!) is amplified by doubling 6.5 times, then that error is applied to a reciprocity graph.

So, while it might be instructive to initially do all this math including filter factors, it is going to involve (sigh) experimentation.

Thanks Rich. Yeah, I'll probably stop at a yellow filter just to provide a bit of contrast and keep times manageable. Should have something to post in a week or two.

rubbernglue · Feb 25, 2017

I normally use red-filters with my pinholecameras (when I use filters) I then add two stops which is normally good enough. Red filters however, don't really do much use is (very) cloudy conditions.

379 retro80s 04 by Johan, on Flickr

KC2PED · Apr 11, 2017

BobClack said:
However, nowhere can I find a chart listing what the increase in exposure time would be using a filter once reciprocity failure is determined for the film.

When using filters I have always applied my filter compensation to the base exposure and then calculated reciprocity based on that

RalphLambrecht · Apr 12, 2017

Sirius Glass said:
Generally each filter has its own filter factor, the following is typical ranges:

Yellow 1 to 2 times longer - filter factor ~= 1 to 1.5

Orange 2 to 3 times longer - filter factor ~= 2 to 2.5

Red 6 to 8 times longer - filter factor ~= 3

Mathematically think 2filter factor = times longer

I agree.these times and factors arevery good starting points.

Leigh B · Apr 12, 2017

KC2PED said:
When using filters I have always applied my filter compensation to the base exposure and then calculated reciprocity based on that

Correct.

RF correction depends on the film. For example, Fuji ACROS requires no compensation out to 120 seconds, and only 1/2 stop out to 1000 seconds.

- Leigh

Newbie Pinhole B&W Filter Question

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