Raking light (workflow)

The principles of this workflow are universally applicable to a wide range of setups, project scope and objects, regardless of their size, material, or complexity, and are considered best practice in professional imaging. It is a conceptual framework designed to guide cultural professionals through the essential stages of a project, from initial planning to final archival, to help making informed decisions about equipment, space, and logistics while ensuring that the final images meet the desired quality requirements.

Workflow

Workflows of the IWG Wiki are not step-by-step tutorials, but rather high-level, informative guides.
For more detailed help to adapt these workflows to your specific needs, please consult with your institutional imaging specialist or get in touch with IWG to find a professional.

Initial assessment and planning

Before any equipment is set up, a clear understanding of the project's goals, constraints, and requirements must be established. Guiding questions can help evaluate the requirements.

Setup

Raking light imaging requires one light source positioned at a shallow angle to the object's surface, typically between 5 and 15 degrees. Following the technique’s general recommendations helps design the photographic setup at best for the given scope.

• Prepare the surface where to place the object. Depending on its scale, it could be a sturdy table, an easel or the floor.
• Select and install the background, if needed.
• Position the radiation sources.
• Position the camera.
• Secure the cables for safety to avoid tripping.
• Position the targets with the gnomon at the center of the scene.
• Set the power of the light sources and the camera settings.
• Set up the working station (i.e. a desk with the computer).
• Adjust the distance of the camera until the desired spatial resolution is achieved.
• Adjust the radiation intensity and/or the camera shutter speed until the correct exposure is met.

Calibration and capture

For raking light capture, the photographic setup does not require calibration, although white balance correction can be advantageous.

• Put the object in place; consider any required mounting.
• Place identification labels, if needed.
• Include targets in the scene, if possible.
• Shoot the required images of the object.
• Check the images for quality review (e.g. focus, composition, glare…). Adjust and re-capture if necessary.

Post-processing and export

This stage involves refining the captured data into a final, usable image.

• Review and select the images.
• Apply the session white balance correction, if possible.
• Fine-tune the global exposure and contrast without altering the visual integrity of the object, if allowed.
• Apply additional non-destructive edits (e.g., corrections for lens distortion and chromatic aberration).
• Embed key metadata (e.g., object ID or accession number, copyright, technical specifications…).
• Export the files in the required format and resolution for its intended use (e.g., TIFF for archive, JPEG for web).
• Apply the required naming convention.

Archival

The final step is to ensure the long-term preservation and accessibility of the images. Guiding questions can help evaluate the requirements.