How can I reduce uneven lighting and harsh highlights in a DIY light tent?

Question

I want to photograph small objects in a DIY light tent/light box and get more even lighting. In many DIY examples online, the lighting still looks patchy or shows bright highlight lines on reflective subjects.

I understand a light tent is meant to diffuse the light, but what makes some tents produce smoother results than others? How should I choose diffusion material, and what setup changes help reduce harsh highlights and uneven illumination?

user37321 · Answer

I am a fan of DIY things for photography. I have constructed PVC lightboxes and light tents.

1. Choose the right material

A lot of these tutorials are made just for the sake of doing things cheaply, not right. So they take a simple waxed paper and think it is enough.

Make a light test

Here are some simulations of how different materials behave. They are not perfect, but give you an idea.

Take your time and get the correct material. Put the material you want to test in front of a light at some distance.

B. The material is too transparent. E.g. Waxed paper.

C. The material is too opaque and only lets light through the thread's spacings. E.g. Beed sheet.

D. The material is diffusive, but the light passes through the thread's spacings, and besides it reflects on the glossy material internally. E.g. Some nylon cloth.

E. Right diffusiveness. It will become more diffusive if the light is further away. E.g. Some nylon cloth, vegetal paper, and synthetic translucent paper, some frosted plastics.

2. Use a double diffusion

Make a setup where you use, the layer on the light tent and an additional layer outside of it. The layers must have a distance between each other.

3. Put the lights further away

If your material is actually diffusive, but you get a hot spot, move the light away.

Aditional note

A bad diffusive material could be enough to photograph matt objects. For example cloth.

But if you have glossy materials, like ceramic, it is more important to get a better material.

The most exigent objects are chromed, metallic, and glass.

But take into account another thing. Good photography is also about light and shadow. Do not try to illuminate something without any reflection or shadow, because it will look flat, without volume.

Even if you are using a lightbox you could put light only on one side. You can even put black cardboard on the other side so the shadows are more prominent. You can also put one light from the top of the box and have a cenital illumination.

Additionally, if an object is glossy or metallic, reflections are now part of the object. It is now impossible to avoid them. The only way to avoid reflection is to turn the lights off.