Light tent help, getting true black BG

[juliushibert]

I've followed the tutorial on here to make a light tent How to Make An Inexpensive Light Tent – DIY and am really impressed with this cheap solution for the results I've managed to get. Thanks.

I've played around with some different with some different coloured infinite back drops—a midtone grey colours seem to work best. Where as the when shooting on black the background is often patchy with noticeable sections of grey rather than a solid black tone. A similar short of thing happens when shooting on a white background. It's never quite crystal white but an off white/grey tint and a noticeable vingette.

This is what I'm using to shoot with;

Canon IXUS 70
Shooting at ISO 80
Mounted on a tripod and put on a timer to minimise camera shake
The light tent is covered in tyvek rather than nylon as it seems to diffuse the light better.
One CFL strip working lamp with a day light lamp in it directly above the light tent

I know the Canon IXUS 70 isn't the best thing in the world to be shooting with and I imagine some of the problems is the limitation of the camera, but unforunately can't upgrade to a DSLR till some more cash rolls in. I've also heard you can install some software on Canon cameras to unlock loads of features? Maybe this is worth a shot.

I've attached some images to show what I'm on about and the last image of WIRED is one of the best images I've managed to take with this setup on the grey BG.

Any advice would be amazing.

[sybren]

Usually when trying to obtain a black background I advise to put more distance between the subject and the background, and to ensure that the background doesn't receive light. Now this is nice and works well, but is hardly doable in a light tent.

Is it possible to remove the rear of the light tent? That way you can have the background further away and outside the light. That would only leave the horizontal surface to worry about. A black cloth like velvet or feace works quite well, as it absorbs a lot of light. You could also get a granite tile or a big shiny laptop (closed, use the back of the monitor for support) as a support surface.

[juliushibert]

The light tent is only made from cheap card so I guess I could just remove the back section of it and give that a try, placing the black card a long way away.

Any ideas why I'm always getting the vignette and anyway to get the white paper backgrounds to be a bright white without blowing out the colour in the object I'm trying to photograph which in most cases is either books or soft toys/knitted items.

[sybren]

Place a light behind the white background, that should blow it out to full white. The vignetting can come from a lot of different things. Move your camera back so that we can see the tent and the lights themselves. If you still have a vignetting around your object, you know it's the illumination and not the lens that causing it.