pure black backgrounds?

[wally_archibald]

<p>Often i see well lit subjects against a deep pure black background, is there a trick to this or is it pains taking tracing and cutting and pasteing. i always assumed it was the latter but some that i see are so detailed at the edges it seems nearly impossible. thanks Wally</p>

[lex_jenkins]

<p>Traditionally it's been done with very careful lighting. Helps to have some distance between the subject and background. The rest is done with lighting confined to the subject. Spill is carefully controlled with various devices, some mounted on the lights themselves (snoots, grids, etc.), others mounted elsewhere (scrims, flags, reflectors, etc.).</p>

<p>Tons of info in photo.net's own Lighting Forum. Also see:<br>

http://www.studiolighting.net/<br>

http://ny.webphotoschool.com/ (one of my favorites for the clearly illustrated tutorials)</p>

[Charles_Webster]

<p>I shoot lots of photos against black backgounds and as Lex says, it's about light control.</p>

<p>I often use a piece of black velvet as a background if it has to be close, but if I can get more than 3 or 4 feet away, I just use a piece of black nylon that serves as a black-out curtain in my studio.</p>

<p>The secret is to keep the light off the background, so if I'm shooting against black, I never use an umbrella, always a softbox. Umbrellas splash light all over the place. I always use honeycomb grids on my strobe reflectors to narrow the beam, and I often use flags to keep light off the background.</p>

<p>If you can't get far from the background, then velvet works well to absorb the excess light, but even the best, deepest velvet has a "pile direction" in which it's going to be just a little shiny and reflect a few highlights.</p>

<p>The book "Light - Science & Magic" has lots of information about how light work and how to control it to your advantage. The Learning tab at the top of this page has a topic on Studio photography that help.</p>

<p><Chas><br /></p>

<p> </p>

[ben_goren]

<p>Wally,</p>

 

<p>The simple answer is: blast enough light onto your subject and any background will go to

black.</p>

 

<p>Similarly, if you blast enough light onto any background, it’ll go to white.</p>

 

<p>The trick is keeping the foreground light to spilling onto the background. (Or vice-versa. I just did some portrait photography this week with a white seamless background in a white room. The background lights created enough bounce that they added some distracting shiny highlights to some faces — but the background is perfectly white!)</p>

 

<p>To know whether or not you’ve got the exposure correct, use a spot meter on the

background. If your exposure is correct for your subject and your background is at least three stops (preferably four or more)

darker than neutral, you’re all set. That can be done outdoors simply by making sure the sun

is shining on your subject and that the background is entirely shaded.</p>

 

<p>If you’re using flash, just make sure the background is as far away as possible and your

flash is near (but, as always, ideally not <em>on</em>) the camera. Again, meter so that the

background is a few stops below neutral and adjust the flash to properly expose your subject. A

black background should “just happen” at that point — even in broad daylight

(assuming you’ve got a powerful enough flash).</p>

 

<p>Cheers,</p>

 

<p>b&</p>

[chris_waller]

<p>I use the same technique that Charles describes. Here's an example of the result. In this case, the background is only about 6 inches behind the leaf.</p><div></div>

[michaelyoung]

<p>As noted, there are several ways of doing this. I like to think in terms of 5 half lives whenever the situation lends itself to being interpreted that way. 5 half lives approaches 100% and has a way of turning up here and there and everywhere in science--not because it's special but because it's convenient.<br>

As it just so happens, it is a wave property of light (3D property rather than 2D) that its intensity over any distance is halved when that distance is doubled so the math is essentially done for us.<br>

Anyway, the only particularly useful application of this is the situation where all lighting is coming front the front and one wishes to avoid flash for whatever reason. (wildlife)<br>

You'd want to make sure any background is at least five times the distance of the subject to the sensor/film plane. This may be easy in a studio and is often impossible in nature. Still, opportunities in nature occasionally present themselves and it's nice to have rough guide of what the numbers need to be.<br>

Other factors, primarily the metering chosen, i.e. "spot" or "center weighted" also factor in so you may have to account for them as well.<br>

You'll see a reflection of this math in the EV adjustment settings of digital SLRs. <br>

Canon and Nikon tend to cut it off around 3 +/- I believe. <br>

This is a more appropriate interpretation of what the human eye can successfully perceive--that which makes a difference to us-- and represents a change of 87.5 percent in the illumination.<br>

Olympus and a couple of others push the ability to adjust EV settings all the way to 5 steps--which is, of course, overkill, but still useful on rare occasions such as in microscopy which is an important field for Olympus. Blah, blah, blah.<br>

Translation: you probably only really need to have a separation factor of "4" and even then if you find yourself unavoidably confronted with a separation factor of 3 you can "cheat" one step by adjusting either your aperture or shutter speed, just one, not both, by one step. That "cheat" will cost you in overall quality so use it judiciously.</p>

[alastair_baker1]

<p>Wally,<br>

The may I do it is to tack a sheet of black fleece material (non reflective) that I found for virtually free up on a wall and along the ground and then stick the subject on it - no science involved but it seems to work.</p>

<p>Alastair</p>

<p> </p><div></div>

[wally_archibald]

<p>Wow, alot to consider and learn here, no single magic bullet but a combination of things, looks like i have some reading to do, thanks everyone for your replies... Wally</p>