Set the negative Calibration Area

Before you start

Open a representative negative and locate the image boundaries. Check whether the other frames have similar positions. Reversal film does not need this step.

Steps

1. Open Calibration Area

   Double-click a negative in the Contact Sheet and choose Calibration Area in the Viewer toolbar, next to Crop. Exit any active picker or editing tool first, and zoom out if needed to see all four sides. Identify the image, clean film base, perforations, and light source before dragging the box edges or corners. This tool is not shown in reversal projects.

   

   Locate the analysis box

   Opening Calibration Area in the Viewer reveals the pale-blue boundary and handles. Drag them to change the analysis area, not the output crop. The next steps explain how to treat the image, base, and perforations.

   

2. Keep the usable exposed image

   Keep the usable image inside the box so the app can analyze its tonal and color range. Do not restrict the selection to a face or a white wall. Check all four edges and leave out the light source, perforations, light leaks, obstructions, and clearly abnormal areas.

   

3. Include a small clean base region if available

   If a clean, uniformly colored, unexposed but developed base region is visible beside the image, include a small portion. Avoid edge lettering, dirt, light leaks, abnormal gaps, and perforations. You do not need the entire film border, and base should not dominate the selection. There is no fixed pixel width or percentage: include enough to see a small clean region. If no usable base is visible, keep the image rather than cutting into the subject to find some, and check several converted frames.

   Film base does not include holes

   This incorrect selection still includes the upper and lower holes. Clean base is film material; the holes transmit light from the lightbox. Including a little base does not mean including the holes.

   

4. Exclude holes, lightbox light, and plastic

   Compare incorrect and correct selections on the same frame. In the wrong selection, red boxes marked 1 identify lightbox light passing through the holes; orange boxes marked 2 identify plastic obstructions. Both are mistakenly inside the pale-blue analysis box. In the correct example, the green outline follows the usable image and leaves these areas outside. A small clean, unexposed but developed base region may be included; a hole is not film base, and plastic is not a dense part of the film.

   

   Pause switchingWrong selectionCorrect selection

   Switches every 2.8 seconds. Red boxes 1 and orange boxes 2 are tutorial annotations, not app selections; green marks the correct area. Check all four sides, move the pale-blue analysis box inward as needed, then click Apply. Use Apply to All only for matching frame formats and positions. Select an image to enlarge the annotations.

5. See how a wrong selection affects conversion

   The first image includes plastic obstructions and light from the lightbox passing through the perforations. The second shows the conversion produced by that incorrect selection. Plastic is not a dense part of the film, and unobstructed light through a hole is not clear film base. Including them can distort density estimates and change the tone and color of the photographs themselves. Correct the area and reanalyze before compensating with exposure or white balance. Back in the Contact Sheet, inspect several frames: roll analysis uses shared information, not just the current photograph.

   

   Pause switchingWrong selectionResulting conversion

   Switches every 2.8 seconds between the wrong selection and its result. This links a selection to its consequence; it is not an aligned before/after view of one image, and the second image is not a corrected result. Pause or select an image to enlarge.

6. Apply and wait for analysis

   Apply sets the area for the current frame; Apply to All sets it for the whole roll. Use Apply to All only if the other frames have matching formats and positions. Calibrating afterward is normal. Wait for it to finish before checking the conversion.

   

   The roll-wide action in the Contact Sheet

   You can also right-click the frame with the intended area in the Contact Sheet and choose Apply Calibration Area to All. This is roll-wide, not limited to a multi-selection. Check frames with different formats or positions separately.