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Rectangular 20 by 24 inch pale blue gel sheet

Rosco

Rosco Cinegel Eighth Blue (1/8 CTB) 20x24" lighting filter

SKU CH-2FG7-0WNE4

An 81 % transmission gel sheet raises tungsten sources from 3200 K to 3300 K with a –12 Mired shift

  • Subtle colour correction with 3200 K to 3300 K shift
  • High 81 % light transmission preserves output
  • Heat-stable deep-dyed base resists studio temperatures
  • Large 20x24 inch sheet covers many fixtures
  • Mired shift of -12 fine-tunes tungsten to daylight

What the filter does

The Rosco Cinegel Eighth Blue (1/8 CTB) is a colour-correction lighting filter supplied as a single 20x24 inch sheet. It raises the colour temperature of a 3200 K tungsten-halogen source to approximately 3300 K, providing a subtle warming compensation for mixed daylight conditions or aging lamps. The deep-dyed polyester base delivers 81 % light transmission with a Mired shift of -12, so output intensity remains high while the colour balance shifts.

Who should use it

Photographers and videographers who need a slight, repeatable correction on tungsten fixtures will find this gel reliable and easy to trim for barn doors or frames. It is not intended for users who require a full CTB conversion to daylight balance or a stronger colour shift than the 1/8 strength provides.

Key specification

The filter transmits 81 % of incident light while moving the source from 3200 K to 3300 K, a combination that determines whether the gel matches the creative or technical correction you need.

Highlights

  • Subtle colour correction with 3200 K to 3300 K shift
  • High 81 % light transmission preserves output
  • Heat-stable deep-dyed base resists studio temperatures
  • Large 20x24 inch sheet covers many fixtures
  • Mired shift of -12 fine-tunes tungsten to daylight

Specifications

No published specifications for this item yet.

Questions about this item

Does the 1/8 CTB filter run hot or lose light when left on a tungsten source all day?

The deep-dyed base is built for heat stability, and the 81% transmission rate means only a modest drop in output during extended use.

What mounting gear do I need before this 20x24" sheet will stay in front of my light?

You will need a frame, gel clips or tape that fits your fixture; the filter itself is a loose sheet with no built-in mounting hardware.

Will this gel still match the output of my older 3200 K tungsten fixtures if I mix them with newer units?

It shifts 3200 K sources to roughly 3300 K with a -12 Mired shift, so older and newer tungsten lights corrected with the same gel will stay consistent.

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