I am long overdue in documenting my work-in-progress plan to build a DIY 4-way motorized masking system and screen frame intended for variable image sizes and aspects up to immersive proportions. Specifically, I plan to allow for seating distance-to-screen-dimension ratios as close as 1.7x screen height. For my seating distance of 8.5 feet, the usable screen area will be about 124"-wide x 60"-tall (2.07-aspect). I have severe limitations on image size due to the 10' depth of my room, and despite folding the light path with a first surface mirror I will be using an ISCO IIIL to achieve enough width for scope content.
Viewing Distance to Image Height Ratio || 2.35:1 || 16:9
2.0x || 52"x124" || 52"x93"
2.4x (casual or low quality content) || 43"x103" || 43"x77"
1.7x (IMAX and some variable-aspect content) || NA || 60"x107"
My plan is to build the screen frame and the masking frame using 80/20 t-slotted extruded aluminum framing. The t-slotted frames are ideal for the masking system as they provide a perfect channel for the mask supports to travel. The masking will be on rollers driven by quiet Somfy Sonesse 30 RS485 motors that provide variable speeds, multiple programmed stop points, etc.
[2016 Nov 1] I sold my Falcon 100"-wide 2.35:1 AT screen two weeks ago, time to finalize the design and build this new screen! In the mean time I'm using an old paint-stained bedsheet tacked to my wall which is passable and has allowed me to play with image sizes; I definitely enjoy the 2.0x image height size for a lot of material but also sometimes find I need to go down to 2.4x for some content -- thus validating to me the need for 4-way variable masking. Currently evaluating other sources of extruded aluminum, e.g. Bosch Rexroth, Misumi, and co-designing a new mounting system for my two projector + mirror setup since the current ceiling mount vibrates significantly when the clothes washer/dryer are in use.
[2016 April 29] Screen size has been finalized to 120" x 60". I recently acquired a used 1.42x ISCO anamorphic lens on the cheap (larger than an ISCO IIIL) that should allow me to fill the planned 120-wide screen comfortably with any future projector (in combination with the mirror). Build is still on hold, however, as time is in short supply since I'm building a deck and will be enjoying the summer weekends with my kids in the great outdoors. I do have a sample of the Dreamscreen V6 material arriving soon; I expect it to be the material that I will use.
[2016 Jan 22] screen build is on hold until I determine which size screen to build: I'm waiting on a polished 1/4-wave float glass mirror sample to see if it has artifacts (my current 4-6 wave float glass mirror has draw line artifacts) or if I'll be limited to using a Navitar lens which will limit me to ~102" wide
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