polarizing filter and white balance

[ali_mama]

I'm always setting my custom white balance with a sheet of white paper but when I'm using a polarizing filter should I set the white balance before putting the filter or after?

[Doug Pardee]

Always take your reference shot under the exact conditions that you'll be taking the shots that you want to have balanced. The same lighting, the same filters, etc.

The point of the reference shot is to tell the camera, "this is what a neutral color looks like under these conditions".

[ali_mama]

Originally Posted by Doug Pardee

Always take your reference shot under the exact conditions that you'll be taking the shots that you want to have balanced. The same lighting, the same filters, etc.

The point of the reference shot is to tell the camera, "this is what a neutral color looks like under these conditions".

I understand that I should take the reference shot with the filter on then - thanks a lot! :-)

[dave_lines]

I have a question,,, what type of white paper are you using? I have used the back of a business card a few times and it worked reasonably well,, but not sure what white is really white.. maybe a piece of matte finish photo paper???? I know there are diff whiteness of diff papers. DAve

[OsmosisStudios]

Originally Posted by dave_lines

I have a question,,, what type of white paper are you using? I have used the back of a business card a few times and it worked reasonably well,, but not sure what white is really white.. maybe a piece of matte finish photo paper???? I know there are diff whiteness of diff papers. DAve

Even if you dont get it perfectly right, you can edit it in RAW to get it juuuuust perfect. i sometimes shoot a business card flat (camera is at 90degrees from the surface of the card) and use it as a baseline in my RAW editing.

[kencaleno]

Select a neutral coloured object to set your white balance
It’s best to avoid using a white target. The camera prefers grey.( Print yourself a grey card: In photoshop-
File> New
Click on background square in toolbox
Select: red 127; green 127; blue 127 from color chart- Print)

[dave_lines]

Originally Posted by kencaleno

Select a neutral coloured object to set your white balance
It’s best to avoid using a white target. The camera prefers grey.( Print yourself a grey card: In photoshop-
File> New
Click on background square in toolbox
Select: red 127; green 127; blue 127 from color chart- Print)

but should I print it on plain paper or matte photo?,, guessing photo.. thanks

[OsmosisStudios]

Originally Posted by kencaleno

Select a neutral coloured object to set your white balance
It’s best to avoid using a white target. The camera prefers grey.( Print yourself a grey card: In photoshop-
File> New
Click on background square in toolbox
Select: red 127; green 127; blue 127 from color chart- Print)

No.
The problems here are countless. For starters, that's an RGB value that your printer will print in CMYK. Most at-home printers arent even that faithful to CMYK. (127,127,127) is 18% grey (strictly speaking, (128,128,128) is, but hey): most meters are calibrated to 12% (18% is for print). Finally, greycards are for EXPOSURE, not whitebalance.

Meters Don't See 18% Gray by Thom Hogan

Using a white card and editing for the white (255,255,255) on a properly exposed shot is the easiest way to get proper white balance.

[kencaleno]

Originally Posted by OsmosisStudios

No.
The problems here are countless. For starters, that's an RGB value that your printer will print in CMYK. Most at-home printers arent even that faithful to CMYK. (127,127,127) is 18% grey (strictly speaking, (128,128,128) is, but hey): most meters are calibrated to 12% (18% is for print). Finally, greycards are for EXPOSURE, not whitebalance.

Meters Don't See 18% Gray by Thom Hogan

Using a white card and editing for the white (255,255,255) on a properly exposed shot is the easiest way to get proper white balance.

From Nature Photography from the Pacific Northwest and beyond by Bob Johnson @ Earthbound Light

White itself isn't generally your best bet since any color sufficiently overexposed will yield pure white. It isn't really the brightness we are interested in measuring anyway but rather the color. For this reason, many photographers make use of a standard gray card instead. When you think about it, it makes perfect sense. It has a nice, medium tone and a neutral hue, and photographers frequently have one anyway for metering. If you point a camera at a gray card and shoot fully on auto exposure, you will get a medium toned result. We know how bright the picture will be, so the only thing in question is what color it will be. Since the gray card actually has a neutral hue, any variation from neutral that the camera records must have come from the color of the light shining on it. To do this, it is important that the frame be completely filled with the color we are measuring to prevent reflections from other objects influencing it.

This method is known as manual or custom white balance and is generally regarded as the most accurate for applications where color accuracy is critical. Fluorescent, halogen and other artificial light sources have a tint as well as a color temperature. Such light sources are notoriously difficult to compensate for but manual white balance is your best bet. Whatever the camera sees it makes neutral, shifting all other colors as needed to compensate.

From www.bythom.com Nikon D200 review (Thom Hogan)

Custom white balance can be done from a gray card. Kelvin settings can be set directly (though at pre-determined values). White balance settings can be named.

Problem with using white as a reference,is that white is not finite-you can get several different brands of white copy paper,and each will be a different shade of white.

Ken

[ali_mama]

all of this is very enlightening! I'll try a gray card - until now I've been using an ordinary A4 all-purpose paper folded in half to not be transparent and holding it in front of the camera...