Making primitive striplights for bottel shots..

Hi . i need to do some images of a 1 l. bottel standing on a plexiglass plate

on a black background. I want to put on some softlight on that bottel and at

the same time reveal the striplight in one of the sides and add some fill on

the other. Question : i have 2 120x60 approx. softboxes i plan to cover up

with some black plastic bags. Question: how narrow do i have to make that

strip to get the disired effekt explained above. ? im open for other

surgestions on how to make cheap striplights. thanks

Believe it or not, but the black plastic trash bags will let enough light through that- depending on subject-to-source distance and light intensity- it might come through and make a mess of a reflective surface like glass or plexi.

I'd try cardboard before I'd use plastic bags. If you've got hot modeling lights the plastic will melt anyhow.

Even foam core mounting board would be better than plastic.

On the other hand, you could use a frame of cardboard with a narrow strip down the center where your "strip light" comes from. Then, cut larger holes on either side of the strip and add as many layers as you need- of the black plastic- to REDUCE the light. If you're real lucky, the bag plastic might act as a density filter. (You can BOTH use the strip highlight with the unblocked light source, AND a lower level of soft light produced by shooting through the plastic-covered windows.)

As alternative material, you could use thin plywood, mat board, art board / gatorboard, bulk cloth (sometimes you can heavily diffuse and reduce light with the right material,) aluminum roof flashing, etc.

If you do a lot of this, you could make yourself a set of barn doors using plywood or other building material; or purchase (expensive) 1/4" PVC sheets that will keep things rigid, light, and moisture proof.