25 red or polarizer?

[Vaughn]

...What is missing in this discussion is the type of light, the colours in the scene, and particularly the saturation of those colours...

Considering the type of film is important, also. I used TMax100 a lot, and as I usually prefer light skies, I rarely used a filter on it, where I might use a yellow filter on Tri-X or FP4 to get similar skies.

I used a red filter on this image. The idea was to bring the values of the sky and sea closer to the values under the wharf to make printing easier (silver gelatin). I think it worked (I liked the longer exposure's affect on the water, also). I actually ended up doing some burning under the wharf to darken its underside a bit, but keeping detail (that may not show well on the screen).

Gowland 4x5, 150mm lens, TMax100 in HC-110, Ilford Gallerie

 

[pentaxuser]

Thanks for the info and links, David. It looks as if the Kodak hood and filter holder doesn't require an adaptor ring to fit the thread on your lens but simply adapts to all lenses by the use of the three screws similar to the way that Ilford under the lens filter holder fits an enlarger lens?

Have I got this correct? Presumably the filter holder only holds one filter at a time?

Do you or anyone else know who stocks a Wratten 12 Minus Blue round glass filter?

I don't wish to sound ungrateful in advance but as I am U.K. based then there is probably little point in any U.S. based APUGers given me U.S. stockists.

Thanks

pentaxuser

 

[cowanw]

Thanks for the info and links, David. It looks as if the Kodak hood and filter holder doesn't require an adaptor ring to fit the thread on your lens but simply adapts to all lenses by the use of the three screws similar to the way that Ilford under the lens filter holder fits an enlarger lens?

Have I got this correct? Presumably the filter holder only holds one filter at a time?

Do you or anyone else know who stocks a Wratten 12 Minus Blue round glass filter?

I don't wish to sound ungrateful in advance but as I am U.K. based then there is probably little point in any U.S. based APUGers given me U.S. stockists.

Thanks

pentaxuser

The only place I have heard of the Wratten 12 round filter is in the german catalogue for Heliopan. The 1012 is described as a Wratten 12.
See here
Dead Link Removed
and here
http://www.heliopan.de/produkte/schwarz-weiss-filter/
Heliopan is distributed in the US by HP marketing so maybe Bob Salomon can help.

 

[Paul Glover]

David, thanks for the enlightening information about the #12 deep yellow. I'd never really considered it, already having both an orange #15 and yellow #8 and figuring it was just an "in between" filter, but it sounds like an altogether different tool than the orange and yellow filters are and would probably match what I want to do very nicely. I lean toward higher contrast filters like the orange and deep red because of the hazy washed out skies here in summer, but don't always want the added shadow contrast I get with the #29 in particular.

I note that B&H carry a Hoya version of the #12, but can't find a B+W anywhere. Is this a filter they make? I like my Hoya filters, but the B+W #29 I have is something else entirely.

 

[StoneNYC]

Do you know what the B+W number is?

My B+W yellow is 022 my red is 090, I believe my red is the Red#25 equivalent but don't know what my yellow is.


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[cowanw]

from John Koehrer
A really useful booklet from B+W is their catalog, if you can get hold of one. Try calling Schneider USA My biggest problem is fin ding it when I need the information.
According to the book a B+W 023 is a dark yellow with a factor of 3 and has no Wratten equivalent.
The book I have lists the following:
B+W # (wratten #)
UV (010)
021 light yellow (2E)
022 med yellow (8)
023 dark yellow ---
040 yellow-orange (16)
041 red-orange (22)

You also have to keep in mind appearance isn't everything and the response B&W film is not the same as the eye's response.

Subsequent discussion suggests the 023 is like a Wratten 15

 

[David Allen]

Thanks for the info and links, David. It looks as if the Kodak hood and filter holder doesn't require an adaptor ring to fit the thread on your lens but simply adapts to all lenses by the use of the three screws similar to the way that Ilford under the lens filter holder fits an enlarger lens? Have I got this correct? Presumably the filter holder only holds one filter at a time?

Yes the filter holder attaches to the outside of the lens so can be adapted to a wide range of lenses.

Do you or anyone else know who stocks a Wratten 12 Minus Blue round glass filter?

Sorry, but I have only used the Kodak gel filters and have never looked for circular glass filters. The Kodak filter holder fitted all of my 5 x 4" lenses when I used to do landscape photography.

That is what it is. In between. There is nothing particularly special about it. As the Wratten # increases in the yellow to orange to red, absorption moves to the right in the spectrum (see the spectral characteristic graphs in the attached Kodak document). Note there is a slope in the absorption. These are not absolute "sharp-cutting" filters. They are simply contrast filters.

Sorry but I disagree. There is a clear difference to be seen in the spectral characteristic graphs produced by Kodak. Whilst the Wratten 12 (Minus Blue) falls within a sequence of ascending Wratten numbers that go through from light yellow to red, the difference between the filters is not their 'darkness' or 'colour' but rather the position of the absorption edges in their spectral transmission curves. In contrast to other yellow, orange and red filters, the Wratten 12 (Minus Blue) filter blocks all visible blue light and passes green, red and infrared light.

Given that practical results are the best indicator of how anything really works (as opposed to graphs and formulas) in the field, the Wratten 12 (Minus Blue) produces a much more pronounced effect (in terms of reducing blue) than the (visibly darker looking) Wratten 15 (Dark Yellow) filter and is more akin to the effect of a red filter but without blocking up the shadows and with a much lower filter factor than the red filters.

Where one sees the difference most clearly is in Colour Infra-Red photography where only the Wratten 12 (Minus Blue) blocks all of the blue light - incidentally, this is why the military still use Colour Infra-Red film with a Wratten 12 (Minus Blue) filter because it is almost impossible to replicate the camouflage-revealing effect when using digital sensors.

I personally would recommend photographers try out the Wratten 12 (Minus Blue) - pick up a cheap gel version from the web - and believe that, especially with a filter factor of x1, they will be really surprised at the results.

Bests,

David
www.dsallen.de

 

[StoneNYC]

Your yellow 022 is essentially a Wratten #8. The 090 red is a Wratten #25. If you want more effect than the 022 consider a darker yellow or yellow-orange or light orange.

Thanks, that's kind of what I was saying that I want to consider and orange filter of some kind. Thanks.


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[StoneNYC]

Yes the filter holder attaches to the outside of the lens so can be adapted to a wide range of lenses.



Sorry, but I have only used the Kodak gel filters and have never looked for circular glass filters. The Kodak filter holder fitted all of my 5 x 4" lenses when I used to do landscape photography.



Sorry but I disagree. There is a clear difference to be seen in the spectral characteristic graphs produced by Kodak. Whilst the Wratten 12 (Minus Blue) falls within a sequence of ascending Wratten numbers that go through from light yellow to red, the difference between the filters is not their 'darkness' or 'colour' but rather the position of the absorption edges in their spectral transmission curves. In contrast to other yellow, orange and red filters, the Wratten 12 (Minus Blue) filter blocks all visible blue light and passes green, red and infrared light.

Given that practical results are the best indicator of how anything really works (as opposed to graphs and formulas) in the field, the Wratten 12 (Minus Blue) produces a much more pronounced effect (in terms of reducing blue) than the (visibly darker looking) Wratten 15 (Dark Yellow) filter and is more akin to the effect of a red filter but without blocking up the shadows and with a much lower filter factor than the red filters.

Where one sees the difference most clearly is in Colour Infra-Red photography where only the Wratten 12 (Minus Blue) blocks all of the blue light - incidentally, this is why the military still use Colour Infra-Red film with a Wratten 12 (Minus Blue) filter because it is almost impossible to replicate the camouflage-revealing effect when using digital sensors.

I personally would recommend photographers try out the Wratten 12 (Minus Blue) - pick up a cheap gel version from the web - and believe that, especially with a filter factor of x1, they will be really surprised at the results.

Bests,

David
www.dsallen.de

Want to send me one? I'll do a test and post it 77mm please haha


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[spijker]

The B+W Filter handbook (7 MB) lists the transmission diagrams of their filters. On page 61, 3rd row, 2nd column you'll find the yellow and orange filters. The Wratten 12 (minus blue), which bottoms out at 500 nm seems to fall in between the B+W 022 and 023. The roll-off area seems to be about 50nm for both the B+W as the Wratten 12 filter. There doesn't seem to be much mystery about it all. They're all just optical low-pass filters.

 

[David Allen]

The B+W Filter handbook (7 MB) lists the transmission diagrams of their filters. On page 61, 3rd row, 2nd column you'll find the yellow and orange filters. The Wratten 12 (minus blue), which bottoms out at 500 nm seems to fall in between the B+W 022 and 023. The roll-off area seems to be about 50nm for both the B+W as the Wratten 12 filter. There doesn't seem to be much mystery about it all. They're all just optical low-pass filters.

Hi there,

You are quite correct that the B+W filters 22 and 23 are simple optical low pass filters. What you seem to be missing is that the Wratten 12 (Minus Blue) has both a low pass element where the straight line straddles across 500 nanometers PLUS a highly complex curve that delivers a variable response across the 300 - 343 nanometer spectrum (which is outside of what the typical human eye can respond to: i.e. wavelengths from about 390 to 700 nanometers) but one that film does respond to. You can view the curve here: http://motion.kodak.com/motion/uplo...b_And_Post_Production/Kodak_Filters/W2-12.pdf

However, as stated earlier, the best way to assess the effect of filters is by doing practical tests which, I am sure you will find, demonstrates that the Wratten 12 is indeed a very special filter in terms of the relationship between effect and filter factor.

Bests,

David
www.dsallen.de

 

[cowanw]

I did notice that , but was unable to understand what the effect on film would be.
That is the range of UVA-ish
I searched a bit and found this
http://www.uvcorder.com/pdf/Ultraviolet_Photography_with_Film_App_Note.pdf
which says this
"Standard camera lenses can be used for UV imaging in the near-UV band (340-400nm), although their transmission rolls off below about 330nm. For shorter wavelengths of UV, the standard practice is to use a special lens made of UV-transmitting materials such as quartz and calcium fluorite. These lenses are very expensive and come in a limited range of focal lengths and f/numbers."
Also solo UV exposure times are in the 2-15 minute time frame (http://www.plumeltd.com/artzone/zuvhe.htm) and so would have a small effect at typical shutter speeds.
What effect are you seeing from the UV effect on your Wrattan 12 shots?
Are UV reflectors brighter? What is the benefit seen from the passing of 300-343 wavelengths?
thanks

Hi there,

You are quite correct that the B+W filters 22 and 23 are simple optical low pass filters. What you seem to be missing is that the Wratten 12 (Minus Blue) has both a low pass element where the straight line straddles across 500 nanometers PLUS a highly complex curve that delivers a variable response across the 300 - 343 nanometer spectrum (which is outside of what the typical human eye can respond to: i.e. wavelengths from about 390 to 700 nanometers) but one that film does respond to. You can view the curve here: http://motion.kodak.com/motion/uplo...b_And_Post_Production/Kodak_Filters/W2-12.pdf

However, as stated earlier, the best way to assess the effect of filters is by doing practical tests which, I am sure you will find, demonstrates that the Wratten 12 is indeed a very special filter in terms of the relationship between effect and filter factor.

Bests,

David
www.dsallen.de

 

[spijker]

David, I had seen the dip in the UV region but disregarded it as it is not visible for the human eye. You are right that B&W films are sensitive for UV light. But that would mean that the UV transparency of the Wratten 12 contributes to less darkening of a blue sky. This document show the transmission diagram of the Wratten 12 on page 26 fig. 7 which is also what B+W lists so that's easier to compare than a density diagram. The UV transmission part only reaches about 4% (10^-1.35 density) which is still about 4.5 stops attenuation. The same document lists that many B&W films have a UV absorption overcoat and that typically 50x more exposure is needed for UV light compared to visible light (page 18-19). So I doubt that the UV density dip has a noticeable affect on the photograph.

Your comment that the Wratten 12 "has a strong effect on skies and only has a nominal filter factor of +1." remains of course and that's why it is very useful filter for B&W photography. I have a B+W 040 (orange) with a filter factor of 2 stops. That also darkens greens a bit which I often find useful as well. But if one doesn't want the greens to be affected by the filter then the yellow filters B+W 022, 023 & Wratten 12 would be a better choice.

I agree that testing the effect of the various filters is the best way to go about it.

 

[David Allen]

I did notice that , but was unable to understand what the effect on film would be.
That is the range of UVA-ish
I searched a bit and found this
http://www.uvcorder.com/pdf/Ultraviolet_Photography_with_Film_App_Note.pdf
which says this
"Standard camera lenses can be used for UV imaging in the near-UV band (340-400nm), although their transmission rolls off below about 330nm. For shorter wavelengths of UV, the standard practice is to use a special lens made of UV-transmitting materials such as quartz and calcium fluorite. These lenses are very expensive and come in a limited range of focal lengths and f/numbers."
Also solo UV exposure times are in the 2-15 minute time frame (http://www.plumeltd.com/artzone/zuvhe.htm) and so would have a small effect at typical shutter speeds.
What effect are you seeing from the UV effect on your Wrattan 12 shots?
Are UV reflectors brighter? What is the benefit seen from the passing of 300-343 wavelengths?
thanks

I am no scientist, so am not really qualified to say what the specific effects of the various wavelengths are.

However, in practice:

1. If you use colour infra-red film, the Wratten 12 does the best job of removing blue light.
3. If you want to do the three black and white negatives projected together to create a colour image (as per a previous post) party trick, this only really works convincingly with the Wratten 12 (and the corresponding minus Green and minus Red Wratten filters).
5. If you compare the effect of a Wratten 12 filter on B&W film to any other visually similar yellow filter, you will see a far more pronounced effect from the Wratten 12 filter.

Bests,

David
www.dsallen.de