Design Donut size for 5° ERS barrel?

[Mr.McDude-Fellow]

Hey all, question to those of you who have proper donuts for your lights:

I've a 5° barrel throwing a gobo with text. It looks just awful and I'd very much like to kill some of the bleed and clean it up.

Can anyone advise radius/diameter of a proper 5°donut si that i can make one of my own?

 

[derekleffew]

With donuts, crullers, and danishes, it's always a trade-off between sharpness and intensity. You want it bright and fuzzy or sharp and dim? The smaller the hole the sharper, but less intense. That being said, City Theatrical's are 7" diameter*, so I'd start there. They usually know what they are doing.

*And Apollo concurs.

 

[Amiers]

What’s the square.

 

[derekleffew]

What’s the square.

An embedded jpeg of a donut from CT's site. Odd that lt's not showing; it was before. @dvsDave ?

If I click "Edit" on that post, the picture appears.

 

[dvsDave]

An embedded jpeg of a donut from CT's site. Odd that lt's not showing; it was before. @dvsDave ?

If I click "Edit" on that post, the picture appears.

Not sure. Working theory is that City Theatrical doesn't serve up images on https:// just on http:// and that may have been an issue. I just downloaded the image and uploaded it as an attachment.

 

[RonHebbard]

Hey all, question to those of you who have proper donuts for your lights:

I've a 5° barrel throwing a gobo with text. It looks just awful and I'd very much like to kill some of the bleed and clean it up.

Can anyone advise radius/diameter of a proper 5°donut si that i can make one of my own?

@Mr.McDude-Fellow As an affordable start: Obtain a piece of matte Blackwrap, or even matte black cardboard, cut the piece to a square the size of your 5 degree's frame.
Use a straight edge and a marker to draw center-lines diagonally from corner to corner to locate the precise center.

With a compass, draw a circle around the center point; draw circles of many radii while the center is still there to accurately place your compass point.
Depending upon your matte black material, use a suitable cutter to cut your circle; I'm envisioning an Xacto knife cutting thin aluminum Black Wrap or matte Black Bristol / poster board.
Insert your experimental economy Donut in a frame, place in your 5 degree fixture and test at your desired throw distance, on your desired surface and under the lighting you're planning to employ.

Test: Even your economy donut ought to withstand 15 to 30 seconds without burning / becoming a fire hazard.
Begin with a smaller size hole; test, note results.

Place test donut on a flat surface and, following previously drawn concentric circles, hand cut a larger hole.
Test as above.
Remove, observe, NOTE and repeat as above.

Continue enlarging, observing, NOTING and repeating until your hole size has exceeded your previously noted optimum size.

Refer to your notes and purchase, or make, your custom sized donut; be proud of your achievement, sleep soundly and be happy.
Toodleoo!
Ron Hebbard