background color dilemna

[Ree]

Hi,

I'm trying to take pictures of flowers against a canvas cloth. But I'm not able to capture the background color accurately - it appears beige with yellow tinge - not the creamy white color. Also, it does not show the texture of the canvas cloth.
This is how I'm currently taking these pics -
* set custom white balance using grey card - took a shot of the grey card near the subject (flowers)
* distance between canvas cloth and subject is about 2 to 3 feet
* no extra light on the canvas cloth - just indirect light
* near a window - so, the pic is shot in natural light

I'd appreciate any tips on how I can take a picture with the true background color.

Thanks,
Ree

[Glenn NK]

Ree:

I considered a coloured background but felt that there would never be one colour that would work with everything.

So I opted for a piece of black cloth. I mount one edge of the cloth to a slender bamboo stick which attaches horizontally to two larger bamboo sticks that I can push into the ground behind the flower. The horizontal stick attaches to the vertical sticks with rubber bands. The best rubber bands can be found around any post office box (where the postmen drop them - they are blue).

Purchased the bamboo at a gardening store.

If you click on the link below, the flowers with the black backgrounds were shot using this method.

However, there are often some areas that aren't quite completely black. These areas I treat in Lightroom using the healing tool. One could also use Photoshop (which I don't have).

Glenn

[Glenn NK]

There is another "trick" which I've been using more lately:

Use a large aperture to put the background completely out of focus (however this can require some careful positioning of the camera to keep distracting objects out of view).

Then focus stack to get the entire flower into focus (obviously leaving the bg fuzzy).

Glenn

[Ree]

Glenn, thanks for the tip. You are right, black works well as a background color. I like pictures of flowers against white and black backgrounds - they look really nice - i have been pretty successful at this, but now I'm trying to shoot pics with creamy white background (exactly want the cream shade of canvas cloth).

BTW, the trick to get pitch-black background is to make sure that the black cloth has no light falling on it. I use a black foam board and it works very well.

Ree

[revi]

Your remark about how to get pitch-black:

BTW, the trick to get pitch-black background is to make sure that the black cloth has no light falling on it. I use a black foam board and it works very well.

coupled with this:

* no extra light on the canvas cloth - just indirect light

made me think that you under exposed your creme background. Then it will of course appear darker. Also, with 2-3 feet between subject and background,
the background will be too far away to show any fine texture (it's way out of the DoF zone in close-up photography).

Regards

Remco

[xpatUSA]

. . but now I'm trying to shoot pics with creamy white background (exactly want the cream shade of canvas cloth)
Ree

Assuming you can shoot RAW and open up in Adobe Camera Raw you can mess with the white balance/exposure until the background material looks correct or better yet find an image with exactly the hue, saturation and brightness you want, note the RGB values by color picking and go back to your RAW image and adjust stuff until you get those exact same values. Piece of cake ;-)

Messing with the WB tint and color balance temperature is sorta like adjusting a* and b* in CIELAB color space.

Another way to go is use one of those on-line paint-store color-picker apps that you can download and then determine the properties of that creamy color by experiment, then go back to ACR and start messin' again.

Just to get you going, I color-picked the following creamy properties from here



R,G,B = 248, 243, 223
H,S,B = 48, 10, 97

These numbers suggest that you should expose the backcloth a lot more, as Remco suggested above. A couple of LED floodlamps illuminating the backcloth might give a creamy appearance to the canvas and bring it's exposure up at the same time. Looking again at the numbers above R is almost equal to G so the cream in the pic is yellowish and the blue value, at 223, is reducing the saturation of the yellow hue as is clearly shown by the following HSB figures where saturation is only 10% but brightness is almost to the max at 97%. A hue of 48 (degrees) is not too far from yellow but tending towards red which would be somewhat more obvious if the color were more saturated.

Ted

[Ree]

Remco - Thank you. i'll try to place the flowers closer to the background and also illuminate the background and see if it works.

Ree

[Ree]

Ted - Thanks for the tips. Yes, I shoot in raw - and as you suggest, I'll experiment with WB/exposure in ACR - but won't it change the color of the flowers also?
Ree

[xpatUSA]

Ted - Thanks for the tips. Yes, I shoot in raw - and as you suggest, I'll experiment with WB/exposure in ACR - but won't it change the color of the flowers also?
Ree

My feeling is that, if the canvas is creamy in color and well-lit, adjusting the WB in raw to get that exact same background color will be no different than setting a neutral area to have equal R,G,B i.e. gray. It would be more tricky 'cos you'd be adjusting three sliders instead of two. So, the flowers (in theory :-) should have their colors balanced thereby, rather than unbalanced.

It might be better to get the background exposure set up without flowers first, so that you don't have to mess with the exposure too much in RAW. The flowers would have to have their own exposure then set separately by adjusting lighting rather than changing the camera settings (which would probably mess up your background exposure).

I see the background lit quite strongly from the sides to bring out the weave of the cloth and also to reduce the strength of the shadows of the flowers. As to the flower lighting I'm no expert and have nothing to offer because I don't do that kind of shooting.

Good luck,

Ted