red filter effect in Photoshop

Hi all,

I'm posting this msg to 2 groups hoping to get replies from people in photography field who have exposure to photoshop..

I'd like to know if there is a way to get a red filter effect using Photoshop. I'd like to retouch my b&w photos with the red filter effect. I've heard (but haven't tried myself) that using red filter with b&w photos can create quite dramatic effects as it increases contrast to the photo. I use Pentax SLR but I don't have a red filter. So can someone tell me if there is a way to achieve that effect in Photoshop?

Thanx
Ben

"Ben" wrote in message

Hi all,

I'm posting this msg to 2 groups hoping to get replies from people in photography field who have exposure to photoshop..

I'd like to know if there is a way to get a red filter effect using Photoshop. I'd like to retouch my b&w photos with the red filter effect. I've heard (but haven't tried myself) that using red filter with b&w photos can create quite dramatic effects as it increases contrast to the photo. I use Pentax SLR but I don't have a red filter. So can someone tell me if there is a way to achieve that effect in Photoshop?

Thanx
Ben

Try this --

Convert your photos to RGB,
go to Image / Adjustments / Hue/saturation (Ctrl/U in Windows), tick the Colorize and Preview boxes
move the Hue slider until the photo turns reddish,
move the Saturation slider until you achieve the desired effect.

mm

(Ben) posted:

I'd like to know if there is a way to get a red filter effect using Photoshop.
Ben

Googling for <"red filter" photoshop> gets 1630 results. I'm sure you'll find the answer among them.
- Max

--
MisterMax
Slideshows of Angkor Wat, Bali, Crete, France, Malaysia, Maui, Morocco, Mt Holly, Sicily, St Tropez, Singapore, Thailand, Tour de France: http://buten.net/max/
(Yes,RemoveDoubles is part of my email address. The double letters in my last name are not.)

"Mister Max" wrote in message

(Ben) posted:

I'd like to know if there is a way to get a red filter effect using Photoshop.
Ben

Googling for <"red filter" photoshop> gets 1630 results. I'm sure you'll find the answer among them.
- Max

Fortunately there are plenty of people around who are happy to share their knowledge, rather than repeating the mindless refrain of "Google Google Google".

This is a stand alone small freeware application
FilterSim . It is as close to a photo filter as I have seen. Other stuff on this site they have as plugins , but this is a stand alone . http://www.mediachance.com/digicam/filtersim.htm
I have had other people rave about it in other photoshop newsgroups. Hope it covers the need.

"Ben" wrote in message

Hi all,

I'm posting this msg to 2 groups hoping to get replies from people in photography field who have exposure to photoshop..

I'd like to know if there is a way to get a red filter effect using Photoshop. I'd like to retouch my b&w photos with the red filter effect. I've heard (but haven't tried myself) that using red filter with b&w photos can create quite dramatic effects as it increases contrast to the photo. I use Pentax SLR but I don't have a red filter. So can someone tell me if there is a way to achieve that effect in Photoshop?

Thanx
Ben

max morrison wrote:

"Mister Max" wrote in message

(Ben) posted:

I'd like to know if there is a way to get a red filter effect using Photoshop.
Ben

Googling for <"red filter" photoshop> gets 1630 results. I'm sure you'll find the answer among them.
- Max

Fortunately there are plenty of people around who are happy to share their knowledge, rather than repeating the mindless refrain of "Google Google Google".

And you helped and did it in less than one sentence. Well done. Stan
Visual Arts Photography

"Ben" wrote in message

...
I'd like to know if there is a way to get a red filter effect using Photoshop. I'd like to retouch my b&w photos with the red filter effect.

For photos taken on B&W film, no. The information about different wavelengths that would be required to give the same effect as a red filter is not recorded on B&W film.

If you have a color original, yes. A digital photo or a scan of a photo taken with color film is usually stored as a file containing three "channels" corresponding to red, green, and blue light. The red channel is basically what you would get by taking a B&W photo through a red filter. The green channel is what you would get using a green filter. The blue channel you can guess by now.

I've heard (but haven't tried myself) that using red filter with b&w photos can create quite dramatic effects as it increases contrast to the photo.

A red filter does not increase general contrast. It makes red things appear lighter and blue or green things appear darker. In particular, a red filter makes blue skies darker, while white clouds remain white. So a red filter does increase the contrast of a blue sky with white clouds. But if you lived on a planet with red skies and white clouds, a red filter would decrease the contrast between sky and clouds.

"max morrison" wrote in message

"Mister Max" wrote in message

(Ben) posted:

I'd like to know if there is a way to get a red filter effect using Photoshop.
Ben

Googling for <"red filter" photoshop> gets 1630 results. I'm sure

you'll

find the answer among them.
- Max

Fortunately there are plenty of people around who are happy to share their knowledge, rather than repeating the mindless refrain of "Google Google Google".

Max, sometimes it's better to let them search on their own. I read your suggestion. You're obviously on the Photoshop side, not a photographer, and don't have a clue what he's asking. Nothing wrong with your answer; it just won't do what he's asking. The correct answer is that the color information was already gone when he snapped the shutter. Filtering his grayscale image will only colorize it. In a B&W photograph, the red 29 removes cyan, red's complement. This darkens skies somewhat, and heightens foliage while deepening shadows. Without the original reds, greens, and blues to play with, "filtering" in Photoshop doesn't change anything.

To get anything like a red filter effect you would have to start with a colour picture. From a B/W piece of film you cannot "remove" blue and green (which is what a red filter does) as you don't have any blue or green -- or red for that matter.
For not too much money you could get a Hoya multicoated red filter -- 25 is good for most shooting but a 29 gives nice extremly dark skies, and if you combine it with a polarizor will give you just about black skies when shooting in certain directions. A good mail order shop like Adorama will have good prices. I can't tell you how much the filter would be as it will depend on the size you need.

--
http://www.chapelhillnoir.com
home of The Camera-ist's Manifesto
The Improved Links Pages are at
http://www.chapelhillnoir.com/links/mlinks00.html
A sample chapter from my novel "Haight-Ashbury" is at http://www.chapelhillnoir.com/writ/hait/hatitl.html
"Ben" wrote in message

Hi all,

I'm posting this msg to 2 groups hoping to get replies from people in photography field who have exposure to photoshop..

I'd like to know if there is a way to get a red filter effect using Photoshop. I'd like to retouch my b&w photos with the red filter effect. I've heard (but haven't tried myself) that using red filter with b&w photos can create quite dramatic effects as it increases contrast to the photo. I use Pentax SLR but I don't have a red filter. So can someone tell me if there is a way to achieve that effect in Photoshop?

Thanx
Ben

As Warren and Tony said, if you have a B&W image now, either recorded on B&W film or now in the B&W file format, it is too late to do what a red filter would have done originally. The file does not contain the information the filter (physical or digital) to work with.

--
Joseph E. Meehan

26 + 6 = 1 It's Irish Math

"Ben" wrote in message

Hi all,

I'm posting this msg to 2 groups hoping to get replies from people in photography field who have exposure to photoshop..

I'd like to know if there is a way to get a red filter effect using Photoshop. I'd like to retouch my b&w photos with the red filter effect. I've heard (but haven't tried myself) that using red filter with b&w photos can create quite dramatic effects as it increases contrast to the photo. I use Pentax SLR but I don't have a red filter. So can someone tell me if there is a way to achieve that effect in Photoshop?

Thanx
Ben

"Ben" wrote in message

I'm posting this msg to 2 groups hoping to get replies from people in photography field who have exposure to photoshop..

I'd like to know if there is a way to get a red filter effect using Photoshop. I'd like to retouch my b&w photos with the red filter effect. I've heard (but haven't tried myself) that using red filter with b&w photos can create quite dramatic effects as it increases contrast to the photo. I use Pentax SLR but I don't have a red filter. So can someone tell me if there is a way to achieve that effect in Photoshop?

You can simulate it a bit with landscapes by masking the sky carefully and darkening it some, and by darkening the image overall a bit, with slightly increased contrast...
--
David Ruether

http://www.ferrario.com/ruether

In article ,
says...

Hi all,

I'm posting this msg to 2 groups hoping to get replies from people in photography field who have exposure to photoshop..

I'd like to know if there is a way to get a red filter effect using Photoshop. I'd like to retouch my b&w photos with the red filter effect. I've heard (but haven't tried myself) that using red filter with b&w photos can create quite dramatic effects as it increases contrast to the photo. I use Pentax SLR but I don't have a red filter. So can someone tell me if there is a way to achieve that effect in Photoshop?

Thanx
Ben

I have a tip on my web site on how to simulate a variety of filters by using channels. You need to have a color original for it to work. Follow the tips link on my home page. I think the tip is called "black and white film is obsolete" or something similar..

--
Robert D Feinman

Landscapes, Cityscapes, Panoramas and Photoshop Tips
http://robertdfeinman.com

It is fools like you that are the reason I don't ever read the photoshop forum. Two many arrogant idiots, and no one who actually knows anything.

--
http://www.chapelhillnoir.com
home of The Camera-ist's Manifesto
The Improved Links Pages are at
http://www.chapelhillnoir.com/links/mlinks00.html
A sample chapter from my novel "Haight-Ashbury" is at http://www.chapelhillnoir.com/writ/hait/hatitl.html
"Mister Max" wrote in message

(Ben) posted:

I'd like to know if there is a way to get a red filter effect using Photoshop.
Ben

Googling for <"red filter" photoshop> gets 1630 results. I'm sure you'll find the answer among them.
- Max

--
MisterMax
Slideshows of Angkor Wat, Bali, Crete, France, Malaysia, Maui, Morocco, Mt Holly, Sicily, St Tropez, Singapore, Thailand, Tour de France: http://buten.net/max/
(Yes,RemoveDoubles is part of my email address. The double letters in my last name are not.)

Ben wrote:

Hi all,

I'm posting this msg to 2 groups hoping to get replies from people in photography field who have exposure to photoshop..

I'd like to know if there is a way to get a red filter effect using Photoshop. I'd like to retouch my b&w photos with the red filter effect. I've heard (but haven't tried myself) that using red filter with b&w photos can create quite dramatic effects as it increases contrast to the photo.

I don't know if it should be termed as a contrast change, but the higher grey levels do seem more compressed. There would appear to be more "contrast" between black and white levels, though it is tough to exactly describe it in words.

I use Pentax SLR but I don't have a red filter.
So can someone tell me if there is a way to achieve that effect in Photoshop?

Thanx
Ben

Obviously, the most reliable method is to use a red filter. Also, a dark orange filter can work well. A really dramatic effect is possible using Ilford SFX, and I have several examples on my site of that film.

Anyway, if you want to try it in PhotoShop, and simulate it, you can download and apply this curve:

<http://www.allgstudio.com/support_files/> called RedFilterCurve.hqx. Unfortunately, this files expands only on MacOS. A ZIP encoding for Windows seems to damage the file. If you want a Windows file of this, I can try sending it through e-mail.

The other "LockDownCurve" is a handy tool to use in the Curves control box. This locks down each step, making changes only go where you want them. If you understand the Curves control, then I do not need to explain this further.

Anyway, the RedFilterCurve will work in 16 bit mode as well, and even on colour files that have been converted to greyscale.

Remember, there are always at least three ways to accomplish anything in PhotoShop. A bit of experimenting, and you should find a few more methods.

Ciao!

Gordon Moat
Alliance Graphique Studio
<http://www.allgstudio.com>

(Ben) wrote in message news:...

Hi all,

I'm posting this msg to 2 groups hoping to get replies from people in photography field who have exposure to photoshop..

I'd like to know if there is a way to get a red filter effect using Photoshop. I'd like to retouch my b&w photos with the red filter effect.

Cannot be done.

I've heard (but haven't tried myself) that using red filter with b&w photos can create quite dramatic effects as it increases contrast to the photo. I use Pentax SLR but I don't have a red filter. So can someone tell me if there is a way to achieve that effect in Photoshop?

It cannot be done.

Thanx
Ben

"Ben" wrote in message

I've heard (but haven't tried myself) that using red filter with b&w photos can create quite dramatic effects as it increases contrast to the photo.
Thanx
Ben

A yellow filter on the camera works to increase intensity with black and white shots.

Ron

"Ron" wrote in message

"Ben" wrote in message

I've heard (but haven't tried myself) that using red filter with b&w photos can create quite dramatic effects as it increases contrast to the photo.

A yellow filter on the camera works to increase intensity with black and white shots.

Ummm, that is what the filter sales lit. wants people to believe. Do a test. Shoot the identical real subjects (not color swatches) with and without a light yellow and a medium yellow on the lens. Keep everything identical. Use the exposure settings W/O the filters, then apply the filter-factor specified for the particular filter (TTL meters have too much color error to be correct). Compare the results *on a contact print* where printing differences will be minimal. I don't think you will see any differences. With a dark yellow filter (1-stop FF) on a VERY clear day with sky showing, you *may* see a slight difference. Most weak filters just rob you of some effective film sensitivity, and contribute nothing to the image...
--
David Ruether

http://www.ferrario.com/ruether

"David Ruether" wrote in message

"Ron" wrote in message

"Ben" wrote in message

I've heard (but haven't tried myself) that using red filter with b&w photos can create quite dramatic effects as it increases contrast to the photo.

A yellow filter on the camera works to increase intensity with black and white shots.

Ummm, that is what the filter sales lit. wants people to believe. Do a test. Shoot the identical real subjects (not color swatches) with and without a light yellow and a medium yellow on the lens. Keep everything identical. Use the exposure settings W/O the filters, then apply the filter-factor specified for the particular filter (TTL meters have too much color error to be correct). Compare the results *on a contact print* where printing differences will be minimal. I don't think you will see any differences. With a dark yellow filter (1-stop FF) on a VERY clear day with sky showing, you *may* see a slight difference. Most weak filters just rob you of some effective film sensitivity, and contribute nothing to the image...

What do you consider 'weak' filters, those with one stop or less a factor? Certainly you don't deny that color contrast filters for B&W have no effect!

Ben wrote:

Hi all,

I'm posting this msg to 2 groups hoping to get replies from people in photography field who have exposure to photoshop..

I'd like to know if there is a way to get a red filter effect using Photoshop. I'd like to retouch my b&w photos with the red filter effect. I've heard (but haven't tried myself) that using red filter with b&w photos can create quite dramatic effects as it increases contrast to the photo.

Hi Ben

Don't know if anyone has actually answered your question yet. I got bored reading through the arguments!

Basically - I'm asuming you are scanning your B&W negs in which case, someone has already said, you have lost the info already. BUT let's assume a colour neg original - Scan them in RGB colour. Use photoshop to split the image into red, green and blue channel layers. The red layer will be a very high contrast layer. How you handle the image from there is up to you. You can simply use only the red channel then convert to greyscale or you can use convert all layers to greyscale (best to re-name the layers as red green blue) then use layer transparancy to get exactly the contrast effect you require.

From B&W neg - increase colour depth, then use contrast and gamma and you should get almost the same effect.

I've not been tooo specific here as I don't know whether you're PC or Mac or which version you use.

Hope this helps

David

"jjs" wrote in message

"David Ruether" wrote in message

"Ron" wrote in message

"Ben" wrote in message

I've heard (but haven't tried myself) that using red filter with b&w photos can create quite dramatic effects as it increases contrast to the photo.

A yellow filter on the camera works to increase intensity with black and white shots.

Ummm, that is what the filter sales lit. wants people to believe. Do a test. Shoot the identical real subjects (not color swatches) with and without a light yellow and a medium yellow on the lens. Keep everything identical. Use the exposure settings W/O the filters, then apply the filter-factor specified for the particular filter (TTL meters have too much color error to be correct). Compare the results *on a contact print* where printing differences will be minimal. I don't think you will see any differences. With a dark yellow filter (1-stop FF) on a VERY clear day with sky showing, you *may* see a slight difference. Most weak filters just rob you of some effective film sensitivity, and contribute nothing to the image...

What do you consider 'weak' filters, those with one stop or less a factor? Certainly you don't deny that color contrast filters for B&W have no effect!

"Contrast" is a misnomer if it is taken to refer to image tone contrast change independent of color response - but color filters can be used with panchromatic B&W films to differentiate tones in the image by using color (see above...). What is not often understood, though, is that the weaker color filters have little if any affect on anything other than nearly pure subject colors (so the weaker yellow filters, though often recommended, are generally useless - but a sharp-cutting dark yellow may be useful with a *clear* blue sky). Also, most subject colors are not very pure, so even very strong filters, like red and dark green, may have little visible effect in many B&W images. No strong subject color, no strong filter color, and there is little or no tonal shift in the image and using the filter just wastes film sensitivity. Try sometime shooting a landscape on a clear day with no filter, light yellow, medium yellow, dark yellow, orange, red, light green, and dark green (the commonly-used colored filters for B&W film). Use only the filter-factors (not the TTL meter) for making the corrections to the basic no-filter exposure. Make sure that NOTHING else changes. Contact-print the results and you may be surprised at
the results (or "lack" of them...;-). This test can quickly cure one of false beliefs about filter effects and of the desire to use most filters with B&W film. Anyone want to buy a bunch of nice low-use mint-condition filters in 52mm,
62mm, and 72mm sizes, mostly Nikkors...?;-)
--
David Ruether

http://www.ferrario.com/ruether

"David Ruether" wrote in message

[jjs]
What do you consider 'weak' filters, those with one stop or less a

factor?

Certainly you don't deny that color contrast filters for B&W have no

effect!

"Contrast" is a misnomer if it is taken to refer to image tone contrast change independent of color response - but color filters can be used with panchromatic B&W films to differentiate tones in the image by using color (see above...).

Yes, colored filters are, possibly, misnamed as 'contrast' filters, however they still do produce different contrasts in normal B&W film between colors when compared to an unfiltered image - depending upon the susceptible of the subject and profunditity of the filter.

What is not often
understood, though, is that the weaker color filters have little if any affect on anything other than nearly pure subject colors (so the weaker yellow filters, though often recommended, are generally useless - but a sharp-cutting dark yellow may be useful with a *clear* blue sky).

Of course, there has to be a susceptible blue to contrast.

Also, most subject colors are
not very pure, so even very strong filters, like red and dark green, may have little visible effect in many B&W images.

Now that's where I am puzzled. The subject only has to be "pure enough", or in other words, enough of the color has to exist to be filtered out - contrasted with another color (or just another object of sufficient luminosity), and I submit that unless one exists on the moon such colors/contrasts usually do exist.

For example, if I walk out door of my office I'm not seeing any colors which can be significantly contrasted among others because everything is of mild earth colors, but if I walk outside to the park, the grass and trees and bushes are all within a green that is highly susceptible to green filtration and it appears brighter in the filtered negative compared to surroundings, and if the sky is blue, the sky is as well slightly darker.

Now that said, the effects are sometimes quite subtle. So you were really speaking in sweeping generalities in order to keep the novices from being disappointed, correct? Or is Ithaca really that dull that colored filters do not work?

"jjs" wrote in message

"David Ruether" wrote in message

[jjs]

What do you consider 'weak' filters, those with one stop or less a

factor?

Certainly you don't deny that color contrast filters for B&W have no

effect!

"Contrast" is a misnomer if it is taken to refer to image tone contrast change independent of color response - but color filters can be used with panchromatic B&W films to differentiate tones in the image by using color (see above [deleted] ...).

Yes, colored filters are, possibly, misnamed as 'contrast' filters, however they still do produce different contrasts in normal B&W film between colors when compared to an unfiltered image - depending upon the susceptible of the subject and profunditity of the filter.

Yes, as I said - but most colors in nature are FAR from pure. The exceptions are flowers and a *clear* blue sky...

What is not often
understood, though, is that the weaker color filters have little if any affect on anything other than nearly pure subject colors (so the weaker yellow filters, though often recommended, are generally useless - but a sharp-cutting dark yellow may be useful with a *clear* blue sky).

Of course, there has to be a susceptible blue to contrast.

Yes, but this is rarer than one might think. Even a strong filter will have fairly little effect on a hazy-blue sky...

Also, most subject colors are
not very pure, so even very strong filters, like red and dark green, may have little visible effect in many B&W images.

Now that's where I am puzzled. The subject only has to be "pure enough", or in other words, enough of the color has to exist to be filtered out - contrasted with another color (or just another object of sufficient luminosity), and I submit that unless one exists on the moon such colors/contrasts usually do exist.

Yes - see above - but MOST colors in nature are not pure, and it isn't a matter of a "threshold", but a continuum in the saturation for effect. An absolutely 100% pure color will respond more fully than a 50% saturation color (and this is a rare saturation level in nature...). Do the test I suggested in an earlier post (above), and observe the results - most colors in nature will be little-affected by even strong filtration, and most will be uselessly affected in practice...

For example, if I walk out door of my office I'm not seeing any colors which can be significantly contrasted among others because everything is of mild earth colors, but if I walk outside to the park, the grass and trees and bushes are all within a green that is highly susceptible to green filtration and it appears brighter in the filtered negative compared to surroundings, and if the sky is blue, the sky is as well slightly darker.

The blue sky, *if clear, and down-sun*, will be quite noticeably affected by strong filtration, and somewhat affected by weak filtration, but the green that looks so pure is FAR from it (our eyes are more sensitive to green than to other colors, and what looks pure in green to us isn't...), and even a red or dark green filter will have only a subtle effect on it...

Now that said, the effects are sometimes quite subtle. So you were really speaking in sweeping generalities in order to keep the novices from being disappointed, correct? Or is Ithaca really that dull that colored filters do not work?

Well, yes (;-]) - but only in red-rock high-country desert on a clear day will weak filters have enough effect to bother using them (and strong filters will work wonders...;-). But in most locations, at most times, weak filters will not be worth using. Heck, some people still think a clear UV will help them "cut haze", and therefore a light yellow filter will do wonders - but 'tain't true except in filter-manufacturers' sales literature examples...;-)
Oops! That reminded me of the "multi-coated filter" ad hooey...;-) --
David Ruether

http://www.ferrario.com/ruether

I've heard (but haven't tried myself) that using red filter with b&w photos can create quite dramatic effects as it increases contrast to the photo.

A yellow filter on the camera works to increase intensity with black and white shots.

Ummm, that is what the filter sales lit. wants people to believe. Do a test. Shoot the identical real subjects (not color swatches) with and without a light yellow and a medium yellow on the lens. Keep everything identical. Use the exposure settings W/O the filters, then apply the filter-factor specified for the particular filter (TTL meters have too much color error to be correct). Compare the results *on a contact print* where printing differences will be minimal. I don't think you will see any differences. With a dark yellow filter (1-stop FF) on a VERY clear day with sky showing, you *may* see a slight difference. Most weak filters just rob you of some effective film sensitivity, and contribute nothing to the image...
--
David Ruether

http://www.ferrario.com/ruether

It works for me.

In article <DpzMb.13827$
junk.cornell.edu says...

"Ron" wrote in message

"Ben" wrote in message

I've heard (but haven't tried myself) that using red filter with b&w photos can create quite dramatic effects as it increases contrast to the photo.

A yellow filter on the camera works to increase intensity with black and white shots.

Ummm, that is what the filter sales lit. wants people to believe. Do a test. Shoot the identical real subjects (not color swatches) with and without a light yellow and a medium yellow on the lens. Keep everything identical. Use the exposure settings W/O the filters, then apply the filter-factor specified for the particular filter (TTL meters have too much color error to be correct). Compare the results *on a contact print* where printing differences will be minimal. I don't think you will see any differences. With a dark yellow filter (1-stop FF) on a VERY clear day with sky showing, you *may* see a slight difference. Most weak filters just rob you of some effective film sensitivity, and contribute nothing to the image...

When the yellow filter "rule" was first suggested (probably around 1900) film color sensitivity was not as good as now. There was excessive blue sensitivity and poor red response. The yellow filter helped correct for this. Without the filter the sky appeared blank in many pictures. Photographers used to combine images to show the clouds.

With modern films and proper exposure adjustment, a yellow filter will improve the differentiation beetween white clouds and blue sky and will also lighten green foliage so that it appears closer to what the eye sees. For a stronger effect got to green, orange or finally red filters.

--
Robert D Feinman

Landscapes, Cityscapes, Panoramas and Photoshop Tips
http://robertdfeinman.com

"David Ruether" wrote in message

Yes, colored filters are, possibly, misnamed as 'contrast' filters,

however

they still do produce different contrasts in normal B&W film between

colors

when compared to an unfiltered image - depending upon the susceptible of

the

subject and profunditity of the filter.

Yes, as I said - but most colors in nature are FAR from pure.

One does not need an object of PURE color to filter. It's not a digital on/off effect. Nature is graded.

The exceptions are flowers and a *clear* blue sky...

Well of course. Many new photographers do make the mistake of thinking "red,yellow,green" make the sky darker as if it were a literary effect instead of a color effect. If it ain't blue, it won't filter.

Now that's where I am puzzled. The subject only has to be "pure enough",

or

in other words, enough of the color has to exist to be filtered out - contrasted with another color (or just another object of sufficient luminosity), and I submit that unless one exists on the moon such colors/contrasts usually do exist.

Yes - see above - but MOST colors in nature are not pure, and it isn't a matter of a "threshold", but a continuum in the saturation for effect. An absolutely 100% pure color will respond more fully than a 50% saturation color (and this is a rare saturation level in nature...).

Yes of course. I think I affirmed your statement above. But I submit that we have a powerful misunderstanding. Like you, I've been a photographer for over thirty years, very much of it in B&W. I know how and when to filter. Perhaps I've intuited color so thoroughly that I don't understand why your objection is so strident.

For example, if I walk out door of my office I'm not seeing any colors

which

can be significantly contrasted among others because everything is of

mild

earth colors, but if I walk outside to the park, the grass and trees and bushes are all within a green that is highly susceptible to green

filtration

and it appears brighter in the filtered negative compared to

surroundings,

and if the sky is blue, the sky is as well slightly darker.

The blue sky, *if clear, and down-sun*, will be quite noticeably affected by strong filtration, and somewhat affected by weak filtration, but the green that looks so pure is FAR from it (our eyes are more sensitive to green than to other colors, and what looks pure in green to us isn't...), and even a red or dark green filter will have only a

subtle

effect on it...

I know. I studied the physiology of vision. Again, I've affirmed your assertion but we don't need PURE. Hell, do you think your green filter is PURE? And, btw, the green filter is your friend if you can appreciate fine resolution - and the subject is susceptible .

"jjs" wrote in message

"David Ruether" wrote in message

Yes, colored filters are, possibly, misnamed as 'contrast' filters,

however

they still do produce different contrasts in normal B&W film between

colors

when compared to an unfiltered image - depending upon the susceptible of

the

subject and profunditity of the filter.

Yes, as I said - but most colors in nature are FAR from pure.

One does not need an object of PURE color to filter. It's not a digital on/off effect. Nature is graded.

Yes, of course, and I noted that, and agreed with you, but again pointed out that most colors in nature are FAR from pure, leaving little for the filter to do. We are going around in circles. Read what I said - I think we are in general agreement...;-)

The exceptions are flowers and a *clear* blue sky...

Well of course. Many new photographers do make the mistake of thinking "red,yellow,green" make the sky darker as if it were a literary effect instead of a color effect. If it ain't blue, it won't filter.

Yes... And if it isn't pure blue, it will not filter much, even if it is blue and a fairly strong appropriate-color filter is used...

Now that's where I am puzzled. The subject only has to be "pure enough",

or

in other words, enough of the color has to exist to be filtered out - contrasted with another color (or just another object of sufficient luminosity), and I submit that unless one exists on the moon such colors/contrasts usually do exist.

Yes - see above - but MOST colors in nature are not pure, and it isn't a matter of a "threshold", but a continuum in the saturation for effect. An absolutely 100% pure color will respond more fully than a 50% saturation color (and this is a rare saturation level in nature...).

Yes of course. I think I affirmed your statement above. But I submit that we have a powerful misunderstanding. Like you, I've been a photographer for over thirty years, very much of it in B&W. I know how and when to filter. Perhaps I've intuited color so thoroughly that I don't understand why your objection is so strident.

It isn't strident - I guess I see as pointless merely repeating what I said already, when we agree. Where we may not agree is in the value of using filters - you may find *possible* very subtle effects in images resulting from using them worth the trouble and loss of effective film sensitivity; I do not - and want to point out to others, particularly those who commonly use the light/medium yellow, believing it to be worthwhile, that it generally isn't (and even stronger filters often have no worthwhile effect in the B&W image - it is worth doing the tests instead of just continuing to use the filters...).

For example, if I walk out door of my office I'm not seeing any colors

which

can be significantly contrasted among others because everything is of

mild

earth colors, but if I walk outside to the park, the grass and trees and bushes are all within a green that is highly susceptible to green

filtration

and it appears brighter in the filtered negative compared to

surroundings,

and if the sky is blue, the sky is as well slightly darker.

The blue sky, *if clear, and down-sun*, will be quite noticeably affected by strong filtration, and somewhat affected by weak filtration, but the green that looks so pure is FAR from it (our eyes are more sensitive to green than to other colors, and what looks pure in green to us isn't...), and even a red or dark green filter will have only a

subtle

effect on it...

I know. I studied the physiology of vision. Again, I've affirmed your assertion but we don't need PURE. Hell, do you think your green filter is PURE? And, btw, the green filter is your friend if you can appreciate fine resolution - and the subject is susceptible .

????
This assumes serious lens color problems that may not exist, or which may not matter for some subjects. And, even the "sharp-cut" filter isn't pure in color, but then, neither is the subject generally pure in color - and both conditions reduce the effect of the filter, which was kinda my point...;-) Or, if you do the tests and find that many filters have no significant effect much of the time, why would you use them except when they *will* have a useful effect? --
David Ruether

http://www.ferrario.com/ruether

"Ron" wrote in message

I've heard (but haven't tried myself) that using red filter with b&w photos can create quite dramatic effects as it increases contrast to the photo.

A yellow filter on the camera works to increase intensity with black and white shots.

Ummm, that is what the filter sales lit. wants people to believe. Do a test. Shoot the identical real subjects (not color swatches) with and without a light yellow and a medium yellow on the lens. Keep everything identical. Use the exposure settings W/O the filters, then apply the filter-factor specified for the particular filter (TTL meters have too much color error to be correct). Compare the results *on a contact print* where printing differences will be minimal. I don't think you will see any differences. With a dark yellow filter (1-stop FF) on a VERY clear day with sky showing, you *may* see a slight difference. Most weak filters just rob you of some effective film sensitivity, and contribute nothing to the image...
--
David Ruether

It works for me.

It is easy to believe it does, but try the experiment described above - you may find the results surprising...;-)
--
David Ruether

http://www.ferrario.com/ruether

"Robert Feinman" wrote in message

In article <DpzMb.13827$
junk.cornell.edu says...

"Ron" wrote in message

"Ben" wrote in message

I've heard (but haven't tried myself) that using red filter with b&w photos can create quite dramatic effects as it increases contrast to the photo.

A yellow filter on the camera works to increase intensity with black and white shots.

Ummm, that is what the filter sales lit. wants people to believe. Do a test. Shoot the identical real subjects (not color swatches) with and without a light yellow and a medium yellow on the lens. Keep everything identical. Use the exposure settings W/O the filters, then apply the filter-factor specified for the particular filter (TTL meters have too much color error to be correct). Compare the results *on a contact print* where printing differences will be minimal. I don't think you will see any differences. With a dark yellow filter (1-stop FF) on a VERY clear day with sky showing, you *may* see a slight difference. Most weak filters just rob you of some effective film sensitivity, and contribute nothing to the image...

When the yellow filter "rule" was first suggested (probably around 1900) film color sensitivity was not as good as now. There was excessive blue sensitivity and poor red response. The yellow filter helped correct for this. Without the filter the sky appeared blank in many pictures. Photographers used to combine images to show the clouds.

Yes, by cutting off the high sensitivity to UV and by reducing the excessive blue response of early film (and lenses, with UV), some problems were reduced - but this would not have made clouds appear...

With modern films and proper exposure adjustment, a yellow filter will improve the differentiation beetween white clouds and blue sky and will also lighten green foliage so that it appears closer to what the eye sees. For a stronger effect got to green, orange or finally red filters.

This is the conventional wisdom (and what filter brochures try so effectively to show...;-), but having done the tests with modern films, even with elevated contrast from extended development to exaggerate the differences, the results were subtle at best even on a clear day with the weaker filters, and only obvious with orange and red (but without the dramatic differences often associated with these filters - and with most differences limited to the blue of the sky...).

--
Robert D Feinman

Landscapes, Cityscapes, Panoramas and Photoshop Tips
http://robertdfeinman.com

--
David Ruether

http://www.ferrario.com/ruether

"David Ruether" wrote in message

"Ron" wrote in message

It works for me.

It is easy to believe it does, but try the experiment described above - you may find the results surprising...;-)

David's going to mess someone up on this 'pure' thing. It's a skewed dialog. Impertinent. Look, color filters for B&W are not pure. B&W film's sensitivity to colors is not even across the so-called visible spectrum. The human eye cannot perceive colors evenly across the physical 'visual' spectrum. Nature has very damned few objects of pure color. Colors change throughout the day, and the farther one is from the equator, the worse it gets through the day (or better, depending upon what you want.) And light filters don't do much, true, but they are far from 'pure' because they _are_ light. The universe ain't perfect! Add to that the fact that so very few people are color conscious or know how to make a proper exposure in the first place and THIS is where to we get off this thread to be OT again: In photoshop, just shitcan all but the Green channel. :) There ya go. Back to digital where nobody but prepress professionals and scientific metricists really _care_ about "photographic" color.

"jjs" wrote in message

"David Ruether" wrote in message

"Ron" wrote in message

It works for me. [the use of a yellow filter]

It is easy to believe it does, but try the experiment described above - you may find the results surprising...;-)

David's going to mess someone up on this 'pure' thing. It's a skewed dialog. Impertinent. Look, color filters for B&W are not pure. B&W film's sensitivity to colors is not even across the so-called visible spectrum. The human eye cannot perceive colors evenly across the physical 'visual' spectrum. Nature has very damned few objects of pure color. Colors change throughout the day, and the farther one is from the equator, the worse it gets through the day (or better, depending upon what you want.) And light filters don't do much, true, but they are far from 'pure' because they _are_ light. The universe ain't perfect! Add to that the fact that so very few people are color conscious or know how to make a proper exposure in the first place and THIS is where to we get off this thread to be OT again: In photoshop, just shitcan all but the Green channel. :) There ya go. Back to digital where nobody but prepress professionals and scientific metricists really _care_ about "photographic" color.

Except for the first line, we are in agreement...! ;-)
--
David Ruether

http://www.ferrario.com/ruether

"David Ruether" wrote in message

This is the conventional wisdom (and what filter brochures try so effectively to show...;-), but having done the tests with modern films, even with elevated contrast from extended development to exaggerate the differences, the results were subtle at best even on a clear day with the weaker filters, and only obvious with orange and red (but without the dramatic differences often associated with these filters - and with most differences limited to the blue of the sky...).

Well, then, we can shoot it in color, and monkey with it in Photoshop. :-p

On Tue, 13 Jan 2004 20:24:18 GMT, "David Ruether" wrote:

"Ron" wrote in message

I've heard (but haven't tried myself) that using red filter with b&w photos can create quite dramatic effects as it increases contrast to the photo.

A yellow filter on the camera works to increase intensity with black and white shots.

Ummm, that is what the filter sales lit. wants people to believe. Do a test. Shoot the identical real subjects (not color swatches) with and without a light yellow and a medium yellow on the lens. Keep everything identical. Use the exposure settings W/O the filters, then apply the filter-factor specified for the particular filter (TTL meters have too much color error to be correct). Compare the results *on a contact print* where printing differences will be minimal. I don't think you will see any differences. With a dark yellow filter (1-stop FF) on a VERY clear day with sky showing, you *may* see a slight difference. Most weak filters just rob you of some effective film sensitivity, and contribute nothing to the image...
--
David Ruether

It works for me.

Possibly the "palest" yellow filter of all, the 2A, contributes a great deal to the image when you have to deal with large amounts of ambient UV light, such as when photographing fluorescent mineral specimens. It performs perfectly, while so-called "UV" filters do nothing to attenuate the near-UV. It is the very characteristic that you mention, in its not contributing anything to the (visible) image, that makes it such an excellent filter for this purpose.

It is easy to believe it does, but try the experiment described above - you may find the results surprising...;-)

On Tue, 13 Jan 2004 04:35:07 GMT, "David Ruether" wrote:

"jjs" wrote in message

"David Ruether" wrote in message

[jjs]

What do you consider 'weak' filters, those with one stop or less a

factor?

Certainly you don't deny that color contrast filters for B&W have no

effect!

"Contrast" is a misnomer if it is taken to refer to image tone contrast change independent of color response - but color filters can be used with panchromatic B&W films to differentiate tones in the image by using color (see above [deleted] ...).

Yes, colored filters are, possibly, misnamed as 'contrast' filters, however they still do produce different contrasts in normal B&W film between colors when compared to an unfiltered image - depending upon the susceptible of the subject and profunditity of the filter.

Yes, as I said - but most colors in nature are FAR from pure. The exceptions are flowers and a *clear* blue sky...

Our brains fail to readily distinguish between pure spectral (monochromatic) colors and those that are "dirty," or spatially distributed about the same wavelength. We normally see the color red, but it is generally a distribution of colors that has a "red" dominance. A case in point would be the appearance of a stoplight created by a matrix of red, monochromatic LEDs in comparison to a traditional one using a red-filtered incandescant source. Interestingly, there have been reports that the "harshness" of monochromatic sources such as this have been found irritating. This might be seen as analogous to a "rich" guitar sound with all it's harmonics in comparison to a pure sinewave. Same note, but the guitar sound has more human appeal.

"Bobs" wrote in message

On Tue, 13 Jan 2004 04:35:07 GMT, "David Ruether"

"jjs" wrote in message

Yes, as I said - but most colors in nature are FAR from pure. The exceptions are flowers and a *clear* blue sky...

Our brains fail to readily distinguish between pure spectral (monochromatic) colors and those that are "dirty," or spatially distributed about the same wavelength.

:) If I may be pedantic, it's the eye and not the brain that cannot make the distinction. There are some colors and juxtapositions of colors that the brain cannot arbitrate because it's not given the data. Nothing in, guesswork out. Guesswork? Yes, the brain will attempt to rationalize perception. It cannot simply do nothing. (We have no bit-bucket!)

The brain, however, is not idle. The human eye has a luminosity sensitivity of about 1:10, however the eye/brain has a particular ability to distinguish boundary differences (and very quickly), and the eye constantly scans, so our impoverished eye-view is hugely enhanced by taking the whole image then brain-processing it.

(Ben) wrote in news:d99e1341.0401101828.40caece6
@posting.google.com:

Hi all,

I'm posting this msg to 2 groups hoping to get replies from people in photography field who have exposure to photoshop..

I'd like to know if there is a way to get a red filter effect using Photoshop. I'd like to retouch my b&w photos with the red filter effect. I've heard (but haven't tried myself) that using red filter with b&w photos can create quite dramatic effects as it increases contrast to the photo. I use Pentax SLR but I don't have a red filter. So can someone tell me if there is a way to achieve that effect in Photoshop?

Thanx
Ben

Not sure this is what you are looking for....
open picture in photoshop
layer via copy
filter gaussian blur (30 to 40)
image adjustments invert
layer mode to overlay
this will lighten the dark areas and bring out many details Hope this helps...