I'm an intern for a lock company and they have me take product shoots of the locks. My Photoflood lights are too harsh to take pictures of the metal without a diffuser. But the diffusers I have right now take away too much light. I have been taking product shoots with a piece of printer paper taped to the lights and it has been working really well but I'm scared they might catch on fire.
What would be the Best Diffuser Umbrella for a Metal Product Shoot? but it doesn't take away too much light?
Metal surfaces are one of the most difficult things to photograph. You're on the right track with using diffused lighting but if, as you say, the diffusers you have are "taking away too much light" then you have to compensate for that by using a tripod and longer shutter speeds.
I've used white umbrellas with the light shining through them to light metal surfaces to good effect, but another method- that of bouncing the light off big sheets of white foam board worked even better. Angling the boards lets you taper the lighting so that you get better definition of the metal surfaces (particularly if there's any engraving on the surface) and strategic placement of a black tape or paper strip or two across the surface of the white board can break up the monotony of the smooth or brushed metal surface.
Another possible option is creating a light tent with white fabric draped around the subject matter but far enough away that it doesn't intrude into the frame and shine your lights through that. There are also ready made light tents or "sheds" made just for this type of "table-top" setup.
Safety first
You do not need Photoflood anymore.
Thoose lamps where from a date that you need somehow well calibrated tungsten lamp on film. But this days you can use a vast array of lamps that generate no heat (or very little) and white balance your camera. You can even use a not that powerfull fluorescent lamp from the kitchen.
What would be the Best Diffuser Umbrella
Do not close your doors. It can be an umbrella, but it can be something else.
There are 2 kinds of umbrella, translucent ones and reflective ones. So there is only one kind of diffuser umbrella for this translucent. For small product shoots, any size (small or big) will do.
The other options are softboxes (rectangular, square, octogonal) does not matter. I prefer rectangulars.
Or if you are on the budget you can use a sheet of vegetal paper. Try not to use a very thin one. Actually sometimes is the best option, no matter the cost.
Or a translucent white fabric. You need it to be waterproof. Not for the water but becouse the pores of the fabric itself.
How to choose a good translucent material?
If you can see thru it and catch what is behind it it is not a good material.
