Pattern Holder

Overview

The Pattern Holder (also known as Gobo Holder) is a frame that holds a gobo or pattern – the metal or glass stencil for projected light patterns – in the gobo slot of a profile spotlight (Ellipsoidal Reflector Spotlight, ERS). A classic application is the ETC Source Four and comparable profile spots from Altman, Strand, or similar manufacturers. The term "Pattern" is the common US designation for a gobo; consequently, "Pattern Holder" and "Gobo Holder" are synonymous.

The frame is slid into the gobo slot at the gate of the spotlight from the front. The gobo sits in the image plane there, so that the sharply focusable pattern is projected through the lens. Closer to the lens – in front of the shutters – there is also an iris or accessory slot, into which, for example, a gobo rotator is inserted.

Types

• Metal/Sandwich Holder: Clamps a steel gobo between two frame halves, holding it flat and acting as a heat sink, which increases the gobo's lifespan.
• Glass Holder: Mount for glass gobos; usually designed as a separate variant, as glass gobos have different thicknesses and tolerances than metal.
• Iris Slot Glass Holder: Inserts a glass gobo into the iris slot. This allows a metal gobo to be used in the regular gobo slot simultaneously. Since iris slot glass holders and gobo rotators occupy the same slot, they cannot be used at the same time.

Sizes

Pattern holders are matched to standardized gobo sizes; each size and each glass/metal type requires a suitable holder. The outer diameters are fixed standard sizes:

For the Source Four, B-Size is the common standard (usable image area approx. 86 × 64.5 mm). Larger A-holders can also accommodate B-metal gobos, depending on the design.

Set Usage

Pattern holders are used to project reproducible light patterns – such as window and Venetian blind shadows (Window/Venetian Breakup), foliage structures (Foliage/Cucoloris patterns), abstract breakups for animating walls, or logos and lettering. Correct orientation is important: the gobo is usually inserted in reverse, as the profile spot's optics invert the image. For long run times or high-powered lamps, the flat seating in the sandwich holder protects the steel gobo from warping.