barndoors not exactly what I expected

Got my first set of barndoors the other day and attempted to gel my background for the first time tonight for only a couple of minutes. I am seeing the opposite of a hot spot (a dark spot) on my background. Why? I am currently not using the grid that came with it. Photos below with two different gel colors, and varying power settings and varying positions of barndoors.

HTTP response: 404 | MIME changed to 'text/html' | Byte size: ZERO

HTTP response: 404 | MIME changed to 'text/html' | Byte size: ZERO

HTTP response: 404 | MIME changed to 'text/html' | Byte size: ZERO

HTTP response: 404 | MIME changed to 'text/html' | Byte size: ZERO

what does it look like without the barndoors?

Scatterbrained wrote in post #15518318
what does it look like without the barndoors?

I have to assume like this (another thread by the OP):
https://photography-on-the.net …/showthread.php​?t=1267518

Looks like a shadow of the strobe cast by the light fixture in the room. Try turning the ambient light off.

It could also be spill hitting the ceiling tiles that is casting the shadow. If turning off the ambient doesn't work, try using cinefoil to control the leaks.

coeng wrote in post #15518294
I am currently not using the grid that came with it.

I think you'll have better luck with the grid (or a snoot), and without the barn doors.

Barn doors are used to keep light from hitting what you don't want it to hit, but they aren't designed to actually shape the light in the way you want.

Curtis N wrote in post #15519558
I think you'll have better luck with the grid (or a snoot), and without the barn doors.

Barn doors are used to keep light from hitting what you don't want it to hit, but they aren't designed to actually shape the light in the way you want.

Wish I knew that beforehand. Could it be that the spot is the shadow that is cast by the light passing over the modeling lamp as it is projected away from the strobe? The strobe is positioned 5 feet from the background.

When I put the grid (that came with the barndoors) on, all I get is a very concentrated blue or red spot, basically the opposite of the dark spot I am talking about.

coeng wrote in post #15520292
Could it be that the spot is the shadow that is cast by the light passing over the modeling lamp as it is projected away from the strobe? The strobe is positioned 5 feet from the background.

The dark spot is obviously a shadow of the background strobe and barndoor unit. The modeling light is in front of the strobe (between the strobe and the shadow) so that cant be it.

Look behind the strobe. As mentioned the shadow is likely cast from a room fixture, spill from one of the lights, or maybe even the key light.

Put your head in the location of the black spot on the background and look at the background light. The source of the light causing the shadow will be directly behind the background light when viewed from the location of the black dot on the background.

The dark spot phenomenon you're seeing is apparently the result of how your barn doors interact with the light's reflector.

coeng wrote in post #15520292
When I put the grid (that came with the barndoors) on, all I get is a very concentrated blue or red spot, basically the opposite of the dark spot I am talking about.

If you want a concentrated (but larger) area of color, then you either need a wider grid (that spreads the light further), or a snoot, or just move the light further from the backdrop.

Looks like a shadow to me and judging from Minnie's shadow there's a light source directly in front. Turn all other lights off and let's see a shot of just the background light.