Too much light, or try different backdrop?

You're using a halogen work light as your light source? I bet that's a warm experience! Along with the grid, you need a fairly light tight wrap to keep light from spilling out the back of the grid. With a light that hot, you need metal, and to remember not to touch it until it cools after use! Is the library attached to a school? Is there a local high school that has a trades class? They might have a metal brake that can bend sheet metal into a box, and a tool to cut the pieces you need for the grid. The size of the openings and the length of the slats determines spread. Once assembled, spray paint the whole thing flat black.
 
So, I was inspired by this post. But, I use strobes, so I don't have to worry quite as much about heat. I decided to make a grid for one of my Bowens lamps.

I started with an empty Maxwell House coffee can, it is the same diameter as the Bowens reflector, so if you cut the middle out of the lid, you get easy attachment. And, I cut the bottom off the can. The can is made of paper so it's easy to cut.

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I stripped the outer plastic cover off the can, which leaves a silver coated paper can, and cut up a box a computer monitor came in, to make the grid. I started with just a square.

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Testing it showed I needed more grid, so I added some more cardboard
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So here is the difference in light between just the can, the square grid and the 3X3 grid

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My suspicion is the cardboard is too heavy, but I spray painted everything mat black and now I have to wait 24 hrs before I can assemble and test. The paint dries to touch in about 15 min. But it is too soft and will scratch if I slide the cardboard into the can because it is a snug fit. If the cardboard is too thick, it will be easy to make a thin version since now I have the template.
Notice how we went from lighting the whole room to just lighting a more or less circular spot. That's what a grid does for you. I have little ones that go on my speedlites. They give a nice round circle of light with pretty even fill, which is the objective here, too. The other thing I could do is fill the end of the can with drinking straws. If I see any black straws for Halloween I might pick up a couple of packs.
 
Have you seen the way Christmas tree ornaments have an inner grid, that is made up of strips which have slits cut into them, where the squares intersect? Do you know what I am talking about? The material? Brass or tin sheeting, cut with tin snips to make the slits where the pieces go together.

OR,go with a bunch of pieces of aluminum or brass square tubing cut into 1.75 inch lengths and epoxied or wired together.THERE's your grid!!! Aluminum Square Tube

That could work pretty well, actually. Sheet metal's not terribly expensive and I've worked with it a lot in the past. Thanks for the suggestion!

You're using a halogen work light as your light source? I bet that's a warm experience! Along with the grid, you need a fairly light tight wrap to keep light from spilling out the back of the grid. With a light that hot, you need metal, and to remember not to touch it until it cools after use! Is the library attached to a school? Is there a local high school that has a trades class? They might have a metal brake that can bend sheet metal into a box, and a tool to cut the pieces you need for the grid. The size of the openings and the length of the slats determines spread. Once assembled, spray paint the whole thing flat black.

Three halogen work lights, actually. It certainly is a warm experience. There is a high school nearby, but my college where I am has a maintenance shop with tools that I can use if necessary (but I've got my own tools that should work if I'm just using sheet metal).
 

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